chore: ignore zero-skills local build artifact

A locally built test binary under this name was accidentally committed
(and has been scrubbed from the branch history); ignore the name so it
cannot recur.

.gitignore

@@ -37,8 +37,13 @@ report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 
 /zero
 /zero.exe
+/zero-skills
 /snake-game.html
 
 # Superpowers skill artifacts (brainstorm mockups, specs, plans) — local only
 .superpowers/
 docs/superpowers/
+
+# Termux/Android build artifacts
+zero-termux-arm64
+zero-linux-sandbox

AGENTS.md

@@ -47,6 +47,12 @@ Tips:
 - In a monorepo, drop a narrower `AGENTS.md` in each sub-tree (e.g. `services/api/AGENTS.md`). Zero picks those up automatically when you launch from inside the sub-tree.
 - A YAML frontmatter block (`---\n...\n---`) at the top is preserved verbatim in the injected prompt but is not parsed for `globs:` or `alwaysApply:` scoping today — keep the body self-contained.
 
+### Personal guidelines, across every project
+
+For preferences that follow *you*, not a specific repo (tone, tooling habits, workflow), drop a `ZERO.md` in your user config directory: `~/.config/zero/ZERO.md` on Linux/macOS, `%AppData%\Roaming\zero\ZERO.md` on Windows — the same directory as `config.json` and your personal specialists. Same format and 8 KiB cap as the project files above, and the same case-insensitive basename match.
+
+This file is injected as its own `## User guidelines` section, before the project's `AGENTS.md`/`ZERO.md`, and is labeled as personal preference in the prompt: project guidelines are the later, more specific instruction and take precedence over it when the two conflict.
+
 ## 2. Custom specialists
 
 Specialists are Zero's sub-agents. Three scopes, in priority order:
@@ -307,6 +313,7 @@ A team that wants every contributor's Zero to behave the same way commits:
 Each contributor adds only:
 
 - `~/.config/zero/config.json` — their personal API keys, theme, default mode.
+- `~/.config/zero/ZERO.md` — personal preferences that follow them across every project (see section 1).
 - `~/.local/share/zero/skills/` — personal skills they keep across projects.
 
 That's it. Run `zero` from the repo root and the agent has the team's full instruction set, every contributor's personal setup, and nothing else.

docs/INSTALL.md

@@ -173,6 +173,61 @@ Linux native sandboxing also requires Bubblewrap to be installed.
 
 macOS uses the system sandbox and does not need an extra helper binary.
 
+### Termux (Android)
+
+Zero can run natively on Android via [Termux](https://termux.dev/). Build with
+`GOOS=android` to avoid the `faccessat2` syscall that is blocked by Samsung's
+seccomp filter on Android:
+
+```bash
+# Install Go in Termux
+pkg install golang
+
+# Build Zero for Android
+git clone https://github.com/Gitlawb/zero.git
+cd zero
+CGO_ENABLED=0 GOOS=android GOARCH=arm64 go build -ldflags="-s -w" -o zero ./cmd/zero
+
+# Move into PATH
+mv zero ~/.local/bin/
+```
+
+> **Why `GOOS=android`?** Go 1.26+ detects `runtime.GOOS == "android"` and skips
+> the `faccessat2` syscall inside `os/exec.findExecutable`, falling back to
+> permission-bit checks. Without this flag, Android's seccomp sends SIGSYS and
+> kills the process whenever Zero looks up a binary on `PATH` (git, sh, etc.).
+
+**DNS.** Android does not expose `/etc/resolv.conf`. Go's pure-Go DNS resolver
+needs one. Use `proot` to bind-mount Termux's resolver config:
+
+```bash
+pkg install proot
+proot -b "$PREFIX/etc/resolv.conf:/etc/resolv.conf" zero
+```
+
+Create a wrapper at `~/.local/bin/zero` to avoid typing proot every time:
+
+```bash
+#!/data/data/com.termux/files/usr/bin/bash
+exec proot -b "$PREFIX/etc/resolv.conf:/etc/resolv.conf" ~/.local/bin/zero.bin "$@"
+```
+
+**Scroll.** On native Termux (not under PRoot), mouse scrolling works out of the
+box. The TUI uses Bubble Tea's `AllMotion` mouse mode by default. If you run Zero
+inside PRoot (e.g. through proot-distro), the scroll fix activates `CellMotion`
+to avoid PRoot's ptrace interference with the 1003 escape sequence.
+
+**Providers.** Zero works with any OpenAI-compatible provider on Termux. For
+example, to use OpenCode Zen's free tier:
+
+```bash
+zero providers add opencode \
+  --name opencode \
+  --model deepseek-v4-flash-free \
+  --base-url https://opencode.ai/zen/v1 \
+  --set-active
+```
+
 Windows source builds can use the main `zero.exe` as the command runner and setup
 helper through Zero's built-in self-dispatch path. If you want a release-style
 layout anyway, build the standalone helper executables next to `zero.exe`:

internal/agent/loop.go

@@ -173,6 +173,7 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 			Messages:        copyMessages(messages),
 			Tools:           exposed,
 			ReasoningEffort: options.ReasoningEffort,
+			PromptCacheKey:  options.SessionID,
 		}
 
 		// Report the per-category context budget for this turn so a surface can
@@ -208,6 +209,7 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 					Messages:        copyMessages(messages),
 					Tools:           exposed,
 					ReasoningEffort: options.ReasoningEffort,
+					PromptCacheKey:  options.SessionID,
 				}
 				// Pre-content connect after a context-limit compaction: route through the
 				// reconnect helper so a transient upstream hiccup here doesn't fail the
@@ -268,6 +270,7 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 					Messages:        copyMessages(messages),
 					Tools:           exposed,
 					ReasoningEffort: options.ReasoningEffort,
+					PromptCacheKey:  options.SessionID,
 				}
 				retryStream, retryStreamErr := streamWithReconnect(ctx, provider, retryRequest, reconnectNoticeFor(options))
 				if retryStreamErr != nil {
@@ -326,6 +329,7 @@ func Run(ctx context.Context, prompt string, provider Provider, options Options)
 				Messages:        copyMessages(messages),
 				Tools:           exposed,
 				ReasoningEffort: options.ReasoningEffort,
+				PromptCacheKey:  options.SessionID,
 			}
 			retryStream, retryErr := streamWithReconnect(ctx, provider, retryRequest, reconnectNoticeFor(options))
 			if retryErr != nil {
@@ -705,6 +709,7 @@ func finalAnswerAfterMaxTurns(ctx context.Context, provider Provider, messages [
 	stream, err := streamWithReconnect(ctx, provider, zeroruntime.CompletionRequest{
 		Messages:        copyMessages(finalMessages),
 		ReasoningEffort: options.ReasoningEffort,
+		PromptCacheKey:  options.SessionID,
 	}, reconnectNoticeFor(options))
 	if err != nil {
 		return "", messages, ""

internal/agent/skills_context_test.go

@@ -7,14 +7,18 @@ import (
 )
 
 func TestSkillsContextCapsLongList(t *testing.T) {
-	skills := make([]SkillInfo, 0, 40)
-	for i := 0; i < 40; i++ {
+	// 60 skills with realistic trigger-rich descriptions (~180 chars each, under
+	// the 200-rune truncation) total well past the 4096-byte list budget, so the
+	// overflow summary must kick in while the block stays bounded.
+	longDesc := strings.Repeat("use when the request touches deployments, release notes, or verification; ", 2) + "number "
+	skills := make([]SkillInfo, 0, 60)
+	for i := 0; i < 60; i++ {
 		n := strconv.Itoa(i)
-		skills = append(skills, SkillInfo{Name: "skill-" + n, Description: "does something useful, number " + n})
+		skills = append(skills, SkillInfo{Name: "skill-" + n, Description: longDesc + n})
 	}
 	got := skillsContext(Options{Skills: skills})
-	if len(got) > 1200 {
-		t.Fatalf("skills block should stay bounded, got %d bytes:\n%s", len(got), got)
+	if len(got) > skillsContextListBudget+1000 {
+		t.Fatalf("skills block should stay bounded near the %d-byte budget, got %d bytes:\n%s", skillsContextListBudget, len(got), got)
 	}
 	if !strings.Contains(got, "more (call skill") {
 		t.Fatalf("expected an overflow summary line, got:\n%s", got)
@@ -25,6 +29,27 @@ func TestSkillsContextCapsLongList(t *testing.T) {
 	}
 }
 
+// A realistic mid-size skill set (20 skills, trigger-rich descriptions) must be
+// listed in FULL — no overflow summary. This pins the fix for the old 640-byte
+// budget, under which skills past ~#6 were invisible to the model and therefore
+// never triggered.
+func TestSkillsContextListsRealisticSetInFull(t *testing.T) {
+	desc := "Use when the user asks about deployments, release notes, or pre-merge verification runs."
+	skills := make([]SkillInfo, 0, 20)
+	for i := 0; i < 20; i++ {
+		skills = append(skills, SkillInfo{Name: "skill-" + strconv.Itoa(i), Description: desc})
+	}
+	got := skillsContext(Options{Skills: skills})
+	if strings.Contains(got, "more (call skill") {
+		t.Fatalf("20 described skills must all be listed without overflow, got:\n%s", got)
+	}
+	for i := 0; i < 20; i++ {
+		if !strings.Contains(got, "- skill-"+strconv.Itoa(i)+":") {
+			t.Fatalf("skill-%d missing from the list:\n%s", i, got)
+		}
+	}
+}
+
 func TestSkillsContext(t *testing.T) {
 	if got := skillsContext(Options{}); got != "" {
 		t.Fatalf("no skills should yield an empty section, got %q", got)

internal/agent/system_prompt.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"unicode/utf8"
 
+	"github.com/Gitlawb/zero/internal/config"
 	"github.com/Gitlawb/zero/internal/repomap"
 	"github.com/Gitlawb/zero/internal/workspaceseed"
 )
@@ -38,6 +39,14 @@ const fallbackSystemPrompt = "You are Zero, a terminal coding agent. Help with t
 // general-to-specific order.
 var projectContextFiles = []string{"AGENTS.md", "ZERO.md", ".zero/AGENTS.md"}
 
+// userContextFile is the per-user instruction file, resolved under
+// config.UserConfigDir()/zero/ alongside the rest of Zero's per-user config
+// (config.json, commands, specialists) so users can keep personal guidance out
+// of individual repositories.
+const userContextFile = "ZERO.md"
+
+var userConfigDirForPrompt = config.UserConfigDir
+
 // maxProjectContextBytes caps how much of a single project doc is injected so
 // a large guidelines file can't blow the context budget.
 const maxProjectContextBytes = 8 << 10 // 8 KiB per file
@@ -81,6 +90,13 @@ func buildSystemPrompt(options Options) string {
 	if seed := workspaceSeedContext(options.Cwd); seed != "" {
 		sections = append(sections, seed)
 	}
+	// User guidelines are injected before workspace/project guidelines so the
+	// project's AGENTS.md/ZERO.md is the later, more specific instruction
+	// block. See userGuidelines for the explicit precedence note carried in
+	// the section text itself.
+	if user := userGuidelines(); user != "" {
+		sections = append(sections, user)
+	}
 	if ws := workspaceContext(options.Cwd); ws != "" {
 		sections = append(sections, ws)
 	}
@@ -175,10 +191,19 @@ func specialistDelegationContext(options Options) string {
 // when no skills are installed, so a skill-less run reproduces the previous prompt
 // byte-for-byte.
 // skillsContextListBudget bounds the bytes spent listing individual skills so a
-// workspace with dozens of them can't bloat every turn's prompt. Skills past the
-// budget are summarized as a count rather than dropped — the model can still load
-// any of them by name (an unknown name returns the full list from the skill tool).
-const skillsContextListBudget = 640
+// workspace with an extreme number of them can't bloat every turn's prompt.
+// Skills past the budget are summarized as a count rather than dropped — the
+// model can still load any of them by name (an unknown name returns the full
+// list from the skill tool).
+//
+// The budget is deliberately generous — roughly 18 skills with maximally long
+// (200-rune, ASCII) descriptions, or 40+ with typical terser ones; non-ASCII
+// descriptions consume it faster since the budget counts bytes. This list is
+// the model's ONLY discovery surface, so a skill squeezed out of it effectively
+// never triggers. The previous 640-byte cap silently broke invocation for
+// anyone with more than ~6 skills — the model cannot match a request against a
+// skill it cannot see.
+const skillsContextListBudget = 4096
 
 func skillsContext(options Options) string {
 	if len(options.Skills) == 0 {
@@ -186,7 +211,7 @@ func skillsContext(options Options) string {
 	}
 	var b strings.Builder
 	b.WriteString("<available_skills>\n")
-	b.WriteString("Reusable, on-demand instruction sets you can load with the skill tool. When a request matches one, call skill with its exact name to pull in its guidance before acting — do not guess names or skip a relevant skill.\n")
+	b.WriteString("Reusable, on-demand instruction sets you can load with the skill tool. Before acting on a request, scan this list; when the request matches a skill's name or description, call skill with its exact name FIRST and follow the loaded guidance — do not guess names, do not skip a matching skill, and do not substitute your own approach for its instructions.\n")
 	listed, spent, omitted := 0, 0, 0
 	for _, info := range options.Skills {
 		name := strings.TrimSpace(info.Name)
@@ -216,9 +241,11 @@ func skillsContext(options Options) string {
 }
 
 // truncateForSkillLine keeps a skill's one-line description short so a single
-// verbose description can't dominate the skills-list budget.
+// verbose description can't dominate the skills-list budget. The cap is roomy on
+// purpose: the description carries the skill's trigger conditions ("use when…"),
+// and truncating those is what stops the model from ever invoking the skill.
 func truncateForSkillLine(desc string) string {
-	const maxDescRunes = 100
+	const maxDescRunes = 200
 	runes := []rune(desc)
 	if len(runes) <= maxDescRunes {
 		return desc
@@ -312,13 +339,7 @@ func projectGuidelines(cwd, gitRoot string) string {
 		if remaining := maxProjectContextTotalBytes - totalUsed; remaining < limit {
 			limit = remaining
 		}
-		if len(content) > limit {
-			cut := limit
-			for cut > 0 && !utf8.RuneStart(content[cut]) {
-				cut--
-			}
-			content = content[:cut] + "\n… (truncated)"
-		}
+		content = truncateGuidelineContent(content, limit)
 		label := projectGuidelineLabel(match, gitRoot)
 		b.WriteString("\n\n## Project guidelines (" + label + ")\n\n" + content)
 		totalUsed += len(content)
@@ -326,6 +347,92 @@ func projectGuidelines(cwd, gitRoot string) string {
 	return b.String()
 }
 
+// userGuidelines returns the per-user ZERO.md instructions block, if present.
+// The file lives in config.UserConfigDir()/zero/ next to Zero's other
+// per-user config; the basename match is case-insensitive so a file saved as
+// zero.md still resolves on case-sensitive filesystems, mirroring the project
+// guideline loader. The section carries an explicit precedence note because
+// this is a global, personal preferences file: it is injected earlier in the
+// prompt than the project's AGENTS.md/ZERO.md (see buildSystemPrompt), and
+// the note keeps that precedence unambiguous even if a model weighs later
+// context more heavily than section order alone implies.
+func userGuidelines() string {
+	configDir, err := userConfigDirForPrompt()
+	if err != nil {
+		return ""
+	}
+	configDir = strings.TrimSpace(configDir)
+	if configDir == "" {
+		return ""
+	}
+	match := findCaseInsensitiveFile(filepath.Join(configDir, "zero"), userContextFile)
+	if match == "" {
+		return ""
+	}
+	data, err := os.ReadFile(match)
+	if err != nil {
+		return ""
+	}
+	content := strings.TrimSpace(string(data))
+	if content == "" {
+		return ""
+	}
+	content = truncateGuidelineContent(content, maxProjectContextBytes)
+	return "## User guidelines (" + filepath.Base(match) + ")\n\n" +
+		"These are the operator's personal preferences, not project policy. " +
+		"Where they conflict with a repository's project guidelines below (AGENTS.md/ZERO.md), the project guidelines take precedence.\n\n" +
+		content
+}
+
+// truncationMarker is appended to guideline content that was cut short.
+const truncationMarker = "\n… (truncated)"
+
+// truncateGuidelineContent caps content at limit bytes without splitting a
+// UTF-8 rune, appending a truncation marker when anything was cut. Space for
+// the marker is reserved before choosing the cut point. When limit is too
+// small to fit the marker itself, the marker is dropped instead, so the
+// returned string never exceeds limit for any non-negative limit.
+func truncateGuidelineContent(content string, limit int) string {
+	if len(content) <= limit {
+		return content
+	}
+	if limit <= 0 {
+		return ""
+	}
+	cut := limit - len(truncationMarker)
+	if cut < 0 {
+		cut = 0
+	}
+	for cut > 0 && !utf8.RuneStart(content[cut]) {
+		cut--
+	}
+	if truncated := content[:cut] + truncationMarker; len(truncated) <= limit {
+		return truncated
+	}
+	// limit is smaller than the marker itself: fall back to a hard,
+	// rune-safe cut at limit bytes with no marker rather than exceeding it.
+	end := limit
+	for end > 0 && !utf8.RuneStart(content[end]) {
+		end--
+	}
+	return content[:end]
+}
+
+// findCaseInsensitiveFile returns the on-disk path of the regular file in dir
+// whose name matches basename case-insensitively, or "" when absent.
+func findCaseInsensitiveFile(dir, basename string) string {
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return ""
+	}
+	for _, e := range entries {
+		if !e.IsDir() && strings.EqualFold(e.Name(), basename) {
+			return filepath.Join(dir, e.Name())
+		}
+	}
+	return ""
+}
+
 // projectGuidelineDirs returns the directory chain from gitRoot to cwd
 // (inclusive), in root-to-leaf order. If gitRoot is empty or unreachable
 // from cwd, the chain collapses to [cwd].
@@ -378,23 +485,16 @@ func projectGuidelineLabel(match, gitRoot string) string {
 // Returns "" when nothing matches.
 func findProjectContextFile(dir string) string {
 	for _, name := range projectContextFiles {
-		baseLower := strings.ToLower(filepath.Base(name))
 		// Walk to the file's parent through dir with case-insensitive segment
-		// matching, then find a regular file with the same lowercased
-		// basename. This works on both case-sensitive and case-insensitive
-		// filesystems and always returns the on-disk filename.
+		// matching, then find a regular file with the same basename. This works
+		// on both case-sensitive and case-insensitive filesystems and always
+		// returns the on-disk filename.
 		parent, ok := resolveDirCaseInsensitive(filepath.Dir(filepath.Join(dir, name)), dir)
 		if !ok {
 			continue
 		}
-		entries, err := os.ReadDir(parent)
-		if err != nil {
-			continue
-		}
-		for _, e := range entries {
-			if !e.IsDir() && strings.ToLower(e.Name()) == baseLower {
-				return filepath.Join(parent, e.Name())
-			}
+		if match := findCaseInsensitiveFile(parent, filepath.Base(name)); match != "" {
+			return match
 		}
 	}
 	return ""

internal/agent/system_prompt.md

@@ -63,6 +63,10 @@ work.
   targeted diffs. Match the existing indentation, imports, and idioms. Match the
   file's comment density: do not add explanatory comments unless the user asks or
   the code is already comment-dense.
+- Solve the problem as posed, not a more general version of it. Add no
+  speculative abstraction, configurability, or handling for cases that cannot
+  occur, and nothing the user did not ask for. A small diff can still be
+  over-built; if a 200-line solution could be 50, rewrite it.
 - Preserve behavior you were not asked to change. Do not delete or rewrite code
   you did not author unless the task requires it; if you must, say so.
 

internal/agent/system_prompt_test.go

@@ -9,6 +9,25 @@ import (
 	"github.com/Gitlawb/zero/internal/sandbox"
 )
 
+// TestMain points userConfigDirForPrompt at an empty, package-wide temp
+// directory for every test in this package. Without this, buildSystemPrompt
+// falls back to the real config.UserConfigDir, so any developer with a
+// personal ~/.config/zero/ZERO.md would get its content folded into
+// otherwise-unrelated prompt assertions, making test runs non-deterministic
+// across contributor machines. Tests that specifically exercise user
+// guidelines stub userConfigDirForPrompt themselves via
+// withSystemPromptTestUserConfigDir(Func) and restore this default on cleanup.
+func TestMain(m *testing.M) {
+	dir, err := os.MkdirTemp("", "zero-agent-tests-*")
+	if err != nil {
+		panic(err)
+	}
+	userConfigDirForPrompt = func() (string, error) { return dir, nil }
+	code := m.Run()
+	os.RemoveAll(dir)
+	os.Exit(code)
+}
+
 func TestCoreSystemPromptIncludesCodingQualityRules(t *testing.T) {
 	prompt := strings.ToLower(buildSystemPrompt(Options{}))
 
@@ -128,6 +147,88 @@ func systemPromptTestBlock(t *testing.T, prompt, start, end string) string {
 	return body
 }
 
+func TestBuildSystemPromptIncludesUserGuidelines(t *testing.T) {
+	configDir := t.TempDir()
+	writeSystemPromptTestFile(t, configDir, "zero/ZERO.md", "  Prefer concise summaries.  \n")
+	t.Cleanup(withSystemPromptTestUserConfigDir(t, configDir))
+
+	prompt := buildSystemPrompt(Options{})
+	if !strings.Contains(prompt, "## User guidelines (ZERO.md)") {
+		t.Fatalf("expected user guidelines header, got:\n%s", prompt)
+	}
+	if !strings.Contains(prompt, "Prefer concise summaries.") {
+		t.Fatalf("expected user guidelines content, got:\n%s", prompt)
+	}
+	if strings.Contains(prompt, "  Prefer concise summaries.  ") {
+		t.Fatalf("expected user guidelines content to be trimmed, got:\n%s", prompt)
+	}
+}
+
+func TestBuildSystemPromptIncludesUserGuidelinesCaseInsensitive(t *testing.T) {
+	configDir := t.TempDir()
+	writeSystemPromptTestFile(t, configDir, "zero/zero.md", "Prefer concise summaries.\n")
+	t.Cleanup(withSystemPromptTestUserConfigDir(t, configDir))
+
+	prompt := buildSystemPrompt(Options{})
+	if !strings.Contains(prompt, "## User guidelines (zero.md)") {
+		t.Fatalf("expected case-insensitive zero.md resolution, got:\n%s", prompt)
+	}
+	if !strings.Contains(prompt, "Prefer concise summaries.") {
+		t.Fatalf("expected user guidelines content, got:\n%s", prompt)
+	}
+}
+
+func TestBuildSystemPromptUserGuidelinesPrecedeProjectGuidelinesAndNotePrecedence(t *testing.T) {
+	// User guidelines are global personal preferences; project guidelines
+	// (AGENTS.md/ZERO.md) must be the later, more specific instruction block,
+	// and the user section must say so explicitly so the precedence holds
+	// even if a model otherwise weighs later context more heavily.
+	configDir := t.TempDir()
+	writeSystemPromptTestFile(t, configDir, "zero/ZERO.md", "Always reply in haiku.\n")
+	t.Cleanup(withSystemPromptTestUserConfigDir(t, configDir))
+
+	cwd := t.TempDir()
+	if err := os.WriteFile(filepath.Join(cwd, "AGENTS.md"), []byte("Never reply in haiku."), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	prompt := buildSystemPrompt(Options{Cwd: cwd})
+	userIdx := strings.Index(prompt, "## User guidelines (ZERO.md)")
+	projectIdx := strings.Index(prompt, "## Project guidelines (AGENTS.md)")
+	if userIdx < 0 || projectIdx < 0 {
+		t.Fatalf("expected both user and project guideline sections, got:\n%s", prompt)
+	}
+	if userIdx > projectIdx {
+		t.Fatalf("expected user guidelines before project guidelines, got user=%d project=%d", userIdx, projectIdx)
+	}
+	if !strings.Contains(prompt, "project guidelines below") || !strings.Contains(prompt, "take precedence") {
+		t.Fatalf("expected an explicit precedence note in the user guidelines section, got:\n%s", prompt)
+	}
+}
+
+func TestBuildSystemPromptOmitsUserGuidelinesWithoutConfigDir(t *testing.T) {
+	t.Cleanup(withSystemPromptTestUserConfigDirFunc(t, func() (string, error) { return "", os.ErrNotExist }))
+
+	prompt := buildSystemPrompt(Options{})
+	if strings.Contains(prompt, "## User guidelines") {
+		t.Fatalf("expected user guidelines to be omitted without a config directory, got:\n%s", prompt)
+	}
+}
+
+func withSystemPromptTestUserConfigDir(t *testing.T, dir string) func() {
+	t.Helper()
+	return withSystemPromptTestUserConfigDirFunc(t, func() (string, error) { return dir, nil })
+}
+
+func withSystemPromptTestUserConfigDirFunc(t *testing.T, fn func() (string, error)) func() {
+	t.Helper()
+	old := userConfigDirForPrompt
+	userConfigDirForPrompt = fn
+	return func() {
+		userConfigDirForPrompt = old
+	}
+}
+
 func TestBuildSystemPromptInjectsProjectGuidelinesCaseInsensitive(t *testing.T) {
 	// Git tracks AGENTS.md on a case-sensitive filesystem; the
 	// loader must still resolve it when the cwd lookup uses lowercase.
@@ -257,6 +358,30 @@ func TestBuildSystemPromptProjectGuidelinesTruncatesAtTotalCap(t *testing.T) {
 	}
 }
 
+func TestTruncateGuidelineContentStaysWithinLimit(t *testing.T) {
+	limit := 64
+	content := strings.Repeat("x", limit+1)
+	got := truncateGuidelineContent(content, limit)
+	if len(got) > limit {
+		t.Fatalf("truncated result is %d bytes, want at most %d", len(got), limit)
+	}
+	if !strings.Contains(got, "truncated") {
+		t.Fatalf("expected truncation marker, got %q", got)
+	}
+}
+
+func TestTruncateGuidelineContentStaysWithinLimitForSmallBudgets(t *testing.T) {
+	// Limits at or below the truncation marker's own length can't fit the
+	// marker at all; the helper must still never exceed the requested limit.
+	content := strings.Repeat("x", 100)
+	for _, limit := range []int{0, 1, len(truncationMarker) - 1, len(truncationMarker), len(truncationMarker) + 1} {
+		got := truncateGuidelineContent(content, limit)
+		if len(got) > limit {
+			t.Fatalf("truncateGuidelineContent(_, %d) = %q (%d bytes), want at most %d bytes", limit, got, len(got), limit)
+		}
+	}
+}
+
 func TestProjectGuidelineDirsOrdersRootToLeaf(t *testing.T) {
 	root := filepath.Join("r")
 	leaf := filepath.Join(root, "a", "b")

internal/cli/app.go

@@ -12,6 +12,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/Gitlawb/zero/internal/agent"
@@ -782,6 +783,14 @@ func runInteractiveTUIWithSetup(stderr io.Writer, deps appDeps, permissionMode a
 			Specialists:    specialistRuntime.specialists,
 			Skills:         pluginActivation.skillInfos(deps.skillsDir()),
 		},
+		// LoadSkills backs /skills and direct /<skill-name> invocation in the TUI.
+		// It resolves against the same merged set (default dir + plugin skill
+		// roots) as the skill tool and the system-prompt list, re-read per use so
+		// newly installed skills work without a restart.
+		LoadSkills: cachedSkillsLoader(func() []skills.Skill {
+			merged, _ := plugins.MergedSkillsLoaded(deps.skillsDir(), pluginActivation.skillRoots)
+			return merged
+		}),
 		PermissionMode: permissionMode,
 		Notify:         resolved.Notify,
 		KeyBindings:    resolved.KeyBindings,
@@ -1277,3 +1286,26 @@ Flags:
 `)
 	return err
 }
+
+// cachedSkillsLoader memoizes a skills loader for a short interval. The TUI
+// calls the loader from autocomplete on every "/x" keystroke; without a cache
+// each keystroke would re-read every SKILL.md body. Two seconds is fresh enough
+// that a newly installed skill still shows up "immediately" while typing.
+func cachedSkillsLoader(load func() []skills.Skill) func() []skills.Skill {
+	var (
+		mu     sync.Mutex
+		at     time.Time
+		cached []skills.Skill
+	)
+	const ttl = 2 * time.Second
+	return func() []skills.Skill {
+		mu.Lock()
+		defer mu.Unlock()
+		if cached != nil && time.Since(at) < ttl {
+			return cached
+		}
+		cached = load()
+		at = time.Now()
+		return cached
+	}
+}

internal/providers/openai/provider.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"strings"
 	"time"
 
@@ -421,6 +422,12 @@ func (provider *Provider) openAIRequest(request zeroruntime.CompletionRequest) c
 	if effort := openAIReasoningEffort(request.ReasoningEffort); effort != "" {
 		mapped.ReasoningEffort = effort
 	}
+	// prompt_cache_key is a documented OpenAI parameter; compatible servers
+	// ignore unknown fields, but a strict endpoint that rejects it can be
+	// accommodated with ZERO_DISABLE_PROMPT_CACHE_KEY=1.
+	if key := strings.TrimSpace(request.PromptCacheKey); key != "" && !promptCacheKeyDisabled() {
+		mapped.PromptCacheKey = key
+	}
 	if len(request.Tools) > 0 {
 		mapped.Tools = make([]toolDefinition, 0, len(request.Tools))
 		for _, tool := range request.Tools {
@@ -437,6 +444,15 @@ func (provider *Provider) openAIRequest(request zeroruntime.CompletionRequest) c
 	return mapped
 }
 
+// promptCacheKeyDisabled reports whether the ZERO_DISABLE_PROMPT_CACHE_KEY
+// kill switch is set to a truthy value. "0" and "false" (any case) are
+// no-ops, matching how ZERO_FORMAT_ON_WRITE parses boolean flags, so an
+// explicitly-disabled toggle never flips the behavior it names.
+func promptCacheKeyDisabled() bool {
+	value := strings.TrimSpace(os.Getenv("ZERO_DISABLE_PROMPT_CACHE_KEY"))
+	return value != "" && value != "0" && !strings.EqualFold(value, "false")
+}
+
 // openAIReasoningEffort normalizes a requested effort to a value the OpenAI chat
 // completions API accepts, or "" to omit the field. "none" (and anything else)
 // is dropped rather than risking a 400 on an unrecognized enum.

internal/providers/openai/provider_test.go

@@ -1259,3 +1259,61 @@ func TestOpenAIRequestEmptyContentHandling(t *testing.T) {
 		t.Fatalf("assistant tool calls dropped: %#v", req.Messages[1])
 	}
 }
+
+// TestOpenAIRequestPromptCacheKey locks in prompt_cache_key forwarding: a
+// session-carrying request serializes the key so the backend can route to a
+// replica holding the cached prefix, a keyless request omits the field
+// entirely (strict servers see byte-identical requests to before), and
+// ZERO_DISABLE_PROMPT_CACHE_KEY suppresses it for endpoints that reject it.
+func TestOpenAIRequestPromptCacheKey(t *testing.T) {
+	provider, err := New(Options{Model: "gpt-test"})
+	if err != nil {
+		t.Fatalf("New returned error: %v", err)
+	}
+	messages := []zeroruntime.Message{{Role: zeroruntime.MessageRoleUser, Content: "hi"}}
+
+	req := provider.openAIRequest(zeroruntime.CompletionRequest{
+		Messages:       messages,
+		PromptCacheKey: "sess_123",
+	})
+	if req.PromptCacheKey != "sess_123" {
+		t.Fatalf("PromptCacheKey = %q, want sess_123", req.PromptCacheKey)
+	}
+	data, err := json.Marshal(req)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	if !strings.Contains(string(data), `"prompt_cache_key":"sess_123"`) {
+		t.Fatalf("prompt_cache_key not serialized: %s", data)
+	}
+
+	req = provider.openAIRequest(zeroruntime.CompletionRequest{Messages: messages})
+	if data, err = json.Marshal(req); err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	if strings.Contains(string(data), "prompt_cache_key") {
+		t.Fatalf("keyless request must omit prompt_cache_key: %s", data)
+	}
+
+	t.Setenv("ZERO_DISABLE_PROMPT_CACHE_KEY", "1")
+	req = provider.openAIRequest(zeroruntime.CompletionRequest{
+		Messages:       messages,
+		PromptCacheKey: "sess_123",
+	})
+	if req.PromptCacheKey != "" {
+		t.Fatalf("kill switch ignored; PromptCacheKey = %q", req.PromptCacheKey)
+	}
+
+	// Explicitly-falsy kill switch values must NOT disable forwarding — only
+	// truthy values flip the toggle (same parsing as ZERO_FORMAT_ON_WRITE).
+	for _, value := range []string{"0", "false", "FALSE"} {
+		t.Setenv("ZERO_DISABLE_PROMPT_CACHE_KEY", value)
+		req = provider.openAIRequest(zeroruntime.CompletionRequest{
+			Messages:       messages,
+			PromptCacheKey: "sess_123",
+		})
+		if req.PromptCacheKey != "sess_123" {
+			t.Fatalf("ZERO_DISABLE_PROMPT_CACHE_KEY=%q must be a no-op; PromptCacheKey = %q", value, req.PromptCacheKey)
+		}
+	}
+}

internal/providers/openai/types.go

@@ -8,6 +8,11 @@ type chatCompletionRequest struct {
 	ReasoningEffort     string           `json:"reasoning_effort,omitempty"`
 	Stream              bool             `json:"stream"`
 	StreamOptions       *streamOptions   `json:"stream_options,omitempty"`
+	// PromptCacheKey asks the backend to route the request to a replica that
+	// already holds this conversation's prefix in its prompt cache (the OpenAI
+	// `prompt_cache_key` parameter). Omitted when the caller carries no session
+	// identity or when ZERO_DISABLE_PROMPT_CACHE_KEY is set.
+	PromptCacheKey string `json:"prompt_cache_key,omitempty"`
 }
 
 // streamOptions requests the final usage chunk on a streaming response. Without

internal/sandbox/manager.go

@@ -3,8 +3,9 @@ package sandbox
 import (
 	"errors"
 	"os"
-	"os/exec"
+	"path/filepath"
 	"runtime"
+	"strings"
 )
 
 // errWindowsSandboxNotInitialized is returned only to a caller that explicitly
@@ -121,9 +122,55 @@ func (manager SandboxManager) Backend() Backend {
 	return manager.backend
 }
 
+// isExecutable checks whether a file is executable. On Unix, this checks the
+// execute permission bits. On Windows, Go's os.FileMode does not set execute
+// bits, so we check for common executable extensions instead.
+func isExecutable(fi os.FileInfo) bool {
+	if !fi.Mode().IsRegular() {
+		return false
+	}
+	if runtime.GOOS == "windows" {
+		name := strings.ToLower(fi.Name())
+		return strings.HasSuffix(name, ".exe") ||
+			strings.HasSuffix(name, ".com") ||
+			strings.HasSuffix(name, ".bat") ||
+			strings.HasSuffix(name, ".cmd")
+	}
+	return fi.Mode()&0o111 != 0
+}
+
+// lookupExecutable checks whether a named binary exists and is executable,
+// using os.Stat instead of exec.LookPath. exec.LookPath internally uses the
+// faccessat2 syscall, which is blocked by Android's seccomp filter (SIGSYS).
+func lookupExecutable(name string) (string, error) {
+	if !strings.Contains(name, string(os.PathSeparator)) {
+		path := os.Getenv("PATH")
+		for _, dir := range strings.Split(path, string(os.PathListSeparator)) {
+			if dir == "" {
+				continue // skip empty entries (e.g. trailing colon)
+			}
+			candidate := filepath.Join(dir, name)
+			if fi, err := os.Stat(candidate); err == nil {
+				if isExecutable(fi) {
+					return candidate, nil
+				}
+			}
+		}
+		return "", errors.New("executable file not found in $PATH")
+	}
+	fi, err := os.Stat(name)
+	if err != nil {
+		return "", err
+	}
+	if isExecutable(fi) {
+		return name, nil
+	}
+	return "", errors.New("executable file not found")
+}
+
 func selectPlatformBackend(goos string, lookup func(string) (string, error)) Backend {
 	if lookup == nil {
-		lookup = exec.LookPath
+		lookup = lookupExecutable
 	}
 	switch goos {
 	case "linux":

internal/tui/assistant_markdown.go

@@ -8,6 +8,7 @@ import (
 	"unicode/utf8"
 
 	"charm.land/lipgloss/v2"
+	"github.com/charmbracelet/x/ansi"
 )
 
 const (
@@ -237,8 +238,10 @@ func renderAssistantMarkdownPlainText(text string, proseMeasure int, tableMeasur
 }
 
 func stripMarkdownRenderControls(text string) string {
-	text = strings.ReplaceAll(text, markdownBoldStart, "")
-	return strings.ReplaceAll(text, markdownBoldEnd, "")
+	// renderAssistantMarkdownText embeds markdownBoldStart/markdownBoldEnd
+	// markers for prose text, and highlightCodeAuto embeds ANSI color sequences
+	// for fenced code blocks. Strip everything so clipboard text is pure plain text.
+	return ansi.Strip(text)
 }
 
 func styleAssistantMarkdownLine(line string, base lipgloss.Style) string {

internal/tui/autocomplete.go

@@ -188,7 +188,54 @@ func (m model) matchCommandSuggestions(token string) []commandSuggestion {
 	out := matchCommandSuggestionsWithFilter(token, func(command commandDefinition) bool {
 		return command.kind != commandSandboxSetup || m.sandboxSetupCommand != nil
 	})
-	return append(out, m.matchUserCommandSuggestions(token)...)
+	out = append(out, m.matchUserCommandSuggestions(token)...)
+	out = append(out, m.matchSkillSuggestions(token)...)
+	// Each source caps itself, but the merged list must honor the shared cap too
+	// (three sources could otherwise stack up to ~3x the palette bound).
+	if len(out) > maxCommandSuggestions {
+		out = out[:maxCommandSuggestions]
+	}
+	return out
+}
+
+// matchSkillSuggestions returns installed skills whose slash name has the typed
+// prefix, so skills are discoverable and invocable from the palette like user
+// commands. Precedence (builtin > user command > skill) is enforced here by
+// skipping any skill whose name is claimed by a builtin (or alias) or a user
+// command — unlike the builtin/user pair, a shadowed skill row would be dead at
+// dispatch time, so it must not be advertised at all.
+func (m model) matchSkillSuggestions(token string) []commandSuggestion {
+	prefix := strings.ToLower(strings.TrimSpace(strings.TrimPrefix(token, "/")))
+	if prefix == "" || m.loadSkills == nil {
+		return nil
+	}
+	taken := m.takenSlashNames()
+	var out []commandSuggestion
+	// Read through the loader (not the startup snapshot in agentOptions) so the
+	// palette matches what dispatch will actually resolve — a skill installed or
+	// removed mid-session appears/disappears without a restart.
+	for _, skill := range m.installedSkills() {
+		name := skillSlashName(skill.Name)
+		if name == "" || taken[name] || !strings.HasPrefix(name, prefix) {
+			continue
+		}
+		// Two skills whose names collide after lowercasing (e.g. "Deploy" and
+		// "deploy") map to one slash name; only the first — the one dispatch will
+		// run — may be advertised, or the row's description and the executed
+		// instructions silently diverge.
+		taken[name] = true
+		desc := strings.TrimSpace(skill.Description)
+		if desc == "" {
+			desc = "Skill: /" + name
+		} else {
+			desc += " (skill)"
+		}
+		out = append(out, commandSuggestion{Name: "/" + name, Desc: desc})
+		if len(out) >= maxCommandSuggestions {
+			break
+		}
+	}
+	return out
 }
 
 // matchUserCommandSuggestions returns file-sourced /commands whose name has the

internal/tui/command_views.go

@@ -698,3 +698,19 @@ func (m model) debugText() string {
 		}},
 	})
 }
+
+// skillsText is the /skills fallback when NO skills are installed — an install
+// hint. With skills present /skills opens the searchable skill picker instead
+// (see newSkillPicker), matching how /model works.
+func (m model) skillsText() string {
+	return renderCommandOutput(commandOutput{
+		Title:  "Skills",
+		Status: commandStatusInfo,
+		Sections: []commandSection{{
+			Lines: []string{"No skills installed."},
+		}},
+		Hints: []string{
+			"install one: create <skills-dir>/<name>/SKILL.md (see `zero skills`)",
+		},
+	})
+}

internal/tui/commands.go

@@ -46,6 +46,7 @@ const (
 	commandCopy
 	commandExport
 	commandNew
+	commandSkills
 	commandUnknown
 )
 
@@ -131,6 +132,13 @@ var commandDefinitions = []commandDefinition{
 		description: "List registered tools.",
 		kind:        commandTools,
 	},
+	{
+		name:        "/skills",
+		usage:       "/skills",
+		group:       commandGroupTools,
+		description: "List installed skills; run one directly with /<skill-name> [args].",
+		kind:        commandSkills,
+	},
 	{
 		name:        "/context",
 		usage:       "/context",

internal/tui/composer.go

@@ -280,7 +280,7 @@ func (m model) composerPositionAtMouse(msg tea.MouseMsg) (int, bool) {
 }
 
 func (m model) composerMouseSelectionBlocked() bool {
-	return m.setup.visible || m.providerWizard != nil || m.mcpAddWizard != nil ||
+	return m.transcriptDetailed || m.setup.visible || m.providerWizard != nil || m.mcpAddWizard != nil ||
 		m.mcpManager != nil || m.picker != nil || m.suggestionsActive()
 }
 

internal/tui/file_view_test.go

@@ -143,7 +143,7 @@ func TestFileViewSwapsTranscriptBody(t *testing.T) {
 	m := filesPanelTestModel()
 	m = m.openFileView("internal/tui/sidebar.go")
 
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	if len(items) != 1 {
 		t.Fatalf("file view should swap the body to a single block item, got %d items", len(items))
 	}
@@ -264,6 +264,55 @@ func TestFileViewFullBodyTruncatesLongFile(t *testing.T) {
 	}
 }
 
+// TestDetailedTranscriptClosesFileView: entering detailed transcript mode
+// closes an active file drill-in so the full transcript body replaces the file
+// content.
+func TestDetailedTranscriptClosesFileView(t *testing.T) {
+	m := filesPanelTestModel()
+	m.altScreen = true
+	m = m.openFileView("web/app.js")
+
+	if !m.fileView.active {
+		t.Fatal("sanity check: openFileView should activate the file view")
+	}
+
+	updated, _ := m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	if m.fileView.active {
+		t.Fatal("detailed transcript should close the file drill-in")
+	}
+	if !m.transcriptDetailed {
+		t.Fatal("Ctrl+O should enter detailed mode")
+	}
+
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", true)
+	if len(items) <= 1 {
+		t.Fatalf("detailed transcript should show multiple body items, got %d", len(items))
+	}
+}
+
+// TestDetailedTranscriptStaysClosedOnSecondToggle: toggling out and back into
+// detailed mode does not re-open the closed file view.
+func TestDetailedTranscriptStaysClosedOnSecondToggle(t *testing.T) {
+	m := filesPanelTestModel()
+	m.altScreen = true
+	m = m.openFileView("web/app.js")
+
+	updated, _ := m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	updated, _ = m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	if m.fileView.active {
+		t.Fatal("exiting detailed mode must not re-open the file drill-in")
+	}
+	if m.transcriptDetailed {
+		t.Fatal("second Ctrl+O should exit detailed mode")
+	}
+}
+
 // TestFileViewKeysDeferToBlockingModal: with a permission prompt up, Esc and
 // the d/f shortcuts belong to the prompt — the drill-in must not swallow them
 // (Esc exiting the view instead of reaching the prompt's deny handling).

internal/tui/files_panel.go

@@ -372,7 +372,7 @@ func (m model) scrollOffsetForTranscriptRow(rowIndex int) (int, bool) {
 		return 0, false
 	}
 	width := m.chatColumnWidth()
-	items := m.transcriptBodyItems(width, "")
+	items := m.transcriptBodyItems(width, "", false)
 	metrics := measureTranscriptBodyItems(items, m.transcriptBodyHeights)
 	startY := -1
 	for _, span := range metrics.spans {

internal/tui/model.go

@@ -29,6 +29,7 @@ import (
 	"github.com/Gitlawb/zero/internal/providers/providerio"
 	"github.com/Gitlawb/zero/internal/sandbox"
 	"github.com/Gitlawb/zero/internal/sessions"
+	"github.com/Gitlawb/zero/internal/skills"
 	"github.com/Gitlawb/zero/internal/streamjson"
 	"github.com/Gitlawb/zero/internal/tools"
 	"github.com/Gitlawb/zero/internal/usage"
@@ -62,6 +63,7 @@ type model struct {
 	ctx                         context.Context
 	cwd                         string
 	userCommands                []usercommands.Command // file-sourced /commands (.zero/commands)
+	loadSkills                  func() []skills.Skill  // lazy installed-skills loader for /skills + /<skill-name>
 	userConfigPath              string
 	doctorUserConfigPath        string
 	projectConfigPath           string
@@ -735,6 +737,7 @@ func newModel(ctx context.Context, options Options) model {
 		cwd:                         cwd,
 		swarmDoneAt:                 map[string]time.Time{},
 		userCommands:                loadedUserCommands,
+		loadSkills:                  options.LoadSkills,
 		composerCursorVisible:       true,
 		userConfigPath:              options.UserConfigPath,
 		doctorUserConfigPath:        doctorUserConfigPath,
@@ -1354,7 +1357,7 @@ func (m model) updateModel(msg tea.Msg) (tea.Model, tea.Cmd) {
 			// home screen or a narrow terminal. Hiding reflows the chat to full
 			// width, so mirror the width-change bookkeeping (re-wrap the streaming
 			// fade, resize the composer) the WindowSizeMsg path does.
-			if m.noBlockingModal() && m.sidebarToggleAllowed() {
+			if !m.transcriptDetailed && m.noBlockingModal() && m.sidebarToggleAllowed() {
 				// Just show/hide — no transcript notice. The reflow IS the feedback,
 				// and emitting a line every toggle piled up noise in the chat.
 				m.sidebarHidden = !m.sidebarHidden
@@ -1421,22 +1424,50 @@ func (m model) updateModel(msg tea.Msg) (tea.Model, tea.Cmd) {
 				return m, nil
 			}
 		case keyIs(msg, tea.KeyPgUp):
-			if m.transcriptDetailed {
-				return m, nil
-			}
-			// A stationary mouse over a bodyY-keyed transcript hover target would
-			// otherwise stay lit at the scrolled-away bodyY until the next real
-			// motion event (see clearHover) — same reasoning as the wheel-scroll
-			// cases in mouse.go.
 			m = m.clearHover()
 			return m.scrollChat(m.chatPageScrollLines()), nil
 		case keyIs(msg, tea.KeyPgDown):
+			m = m.clearHover()
+			return m.scrollChat(-m.chatPageScrollLines()), nil
+		case keyShift(msg) && keyIs(msg, tea.KeyUp):
+			// Shift+Up scrolls the transcript up one line. Must be checked before
+			// plain KeyUp so shifted arrows aren't consumed by the composer-path.
 			if m.transcriptDetailed {
 				return m, nil
 			}
+			if m.pendingPermission != nil {
+				return m.movePermissionCursor(-1), nil
+			}
+			if m.pendingAskUser != nil {
+				return m.moveAskUserCursor(-1), nil
+			}
+			if m.providerWizard != nil {
+				return m.handleProviderWizardKey(msg)
+			}
+			if m.mcpAddWizard != nil {
+				return m.handleMCPAddWizardKey(msg)
+			}
+			if m.mcpManager != nil {
+				return m.handleMCPManagerKey(msg)
+			}
+			if m.picker != nil {
+				if m.modelPickerIsLoading() {
+					return m, nil
+				}
+				m.pickerMoved(-1)
+				return m, nil
+			}
+			if m.suggestionsActive() {
+				break
+			}
+			if m.composerValue() != "" {
+				break // let the input handle multiline navigation
+			}
 			m = m.clearHover()
-			return m.scrollChat(-m.chatPageScrollLines()), nil
-		case keyIs(msg, tea.KeyDown):
+			return m.scrollChat(1), nil
+		case keyShift(msg) && keyIs(msg, tea.KeyDown):
+			// Shift+Down scrolls the transcript down one line. Must be checked
+			// before plain KeyDown so shifted arrows aren't consumed.
 			if m.transcriptDetailed {
 				return m, nil
 			}
@@ -1462,6 +1493,41 @@ func (m model) updateModel(msg tea.Msg) (tea.Model, tea.Cmd) {
 				m.pickerMoved(1)
 				return m, nil
 			}
+			if m.suggestionsActive() {
+				break
+			}
+			if m.composerValue() != "" {
+				break // let the input handle multiline navigation
+			}
+			m = m.clearHover()
+			return m.scrollChat(-1), nil
+		case keyIs(msg, tea.KeyDown):
+			if m.transcriptDetailed {
+				m = m.clearHover()
+				return m.scrollChat(-1), nil
+			}
+			if m.pendingPermission != nil {
+				return m.movePermissionCursor(1), nil
+			}
+			if m.pendingAskUser != nil {
+				return m.moveAskUserCursor(1), nil
+			}
+			if m.providerWizard != nil {
+				return m.handleProviderWizardKey(msg)
+			}
+			if m.mcpAddWizard != nil {
+				return m.handleMCPAddWizardKey(msg)
+			}
+			if m.mcpManager != nil {
+				return m.handleMCPManagerKey(msg)
+			}
+			if m.picker != nil {
+				if m.modelPickerIsLoading() {
+					return m, nil
+				}
+				m.pickerMoved(1)
+				return m, nil
+			}
 			if m.suggestionsActive() {
 				m.moveSuggestion(1)
 				return m, nil
@@ -1480,7 +1546,8 @@ func (m model) updateModel(msg tea.Msg) (tea.Model, tea.Cmd) {
 				return m, nil
 			}
 			if m.transcriptDetailed {
-				return m, nil
+				m = m.clearHover()
+				return m.scrollChat(1), nil
 			}
 			if m.pendingPermission != nil {
 				return m.movePermissionCursor(-1), nil
@@ -1514,6 +1581,48 @@ func (m model) updateModel(msg tea.Msg) (tea.Model, tea.Cmd) {
 			if m.historyRecallActive() {
 				return m.recallHistory(-1), nil
 			}
+		case keyCtrl(msg, 'u'):
+			// Ctrl+U scrolls up half a page, or moves the cursor up in
+			// permission/ask-user prompts. Falls through to the active modal
+			// (wizard, etc.) when none of the above are in focus.
+			if m.transcriptDetailed {
+				return m, nil
+			}
+			if m.pendingPermission != nil {
+				return m.movePermissionCursor(-1), nil
+			}
+			if m.pendingAskUser != nil {
+				return m.moveAskUserCursor(-1), nil
+			}
+			if m.providerWizard != nil || m.mcpAddWizard != nil || m.mcpManager != nil || m.picker != nil || m.pendingSpecReview != nil {
+				break
+			}
+			if m.composerValue() != "" {
+				break // let the input handle its own Ctrl+U (delete-to-bol)
+			}
+			m = m.clearHover()
+			return m.scrollChat(m.chatPageScrollLines()), nil
+		case keyCtrl(msg, 'd'):
+			// Ctrl+D scrolls down half a page, or moves the cursor down in
+			// permission/ask-user prompts. Falls through to the active modal
+			// when none of the above are in focus.
+			if m.transcriptDetailed {
+				return m, nil
+			}
+			if m.pendingPermission != nil {
+				return m.movePermissionCursor(1), nil
+			}
+			if m.pendingAskUser != nil {
+				return m.moveAskUserCursor(1), nil
+			}
+			if m.providerWizard != nil || m.mcpAddWizard != nil || m.mcpManager != nil || m.picker != nil || m.pendingSpecReview != nil {
+				break
+			}
+			if m.composerValue() != "" {
+				break // let the input handle its own Ctrl+D (delete-next-char)
+			}
+			m = m.clearHover()
+			return m.scrollChat(-m.chatPageScrollLines()), nil
 		}
 		if m.transcriptDetailed {
 			return m, nil
@@ -2215,14 +2324,23 @@ func (m model) View() tea.View {
 	}
 	view.ReportFocus = m.notifier != nil
 	if m.wantsMouseCapture() {
-		// AllMotion (not CellMotion) is required for hover highlighting: it
-		// reports cursor movement even with no button pressed. CellMotion only
-		// reports motion while a button is held (drag) — see bubbletea's
-		// MouseMode docs. AllMotion has marginally worse terminal compatibility
-		// but is well supported by the terminals this app targets; the existing
-		// 15ms mouse-event throttle (mouseEventThrottleInterval) already bounds
-		// the redraw rate from the extra motion events.
-		view.MouseMode = tea.MouseModeAllMotion
+		if isRunningUnderPRoot() {
+			// Under PRoot the AllMotion (1003) sequence doesn't work
+			// reliably, breaking touch-gesture scrolling. Fall back to
+			// CellMotion which still delivers wheel events, clicks, and
+			// drag — the only thing lost is hover-highlighting.
+			view.MouseMode = tea.MouseModeCellMotion
+		} else {
+			// AllMotion (not CellMotion) is required for hover highlighting:
+			// it reports cursor movement even with no button pressed.
+			// CellMotion only reports motion while a button is held (drag) —
+			// see bubbletea's MouseMode docs. AllMotion has marginally worse
+			// terminal compatibility but is well supported by the terminals
+			// this app targets; the existing 15ms mouse-event throttle
+			// (mouseEventThrottleInterval) already bounds the redraw rate
+			// from the extra motion events.
+			view.MouseMode = tea.MouseModeAllMotion
+		}
 	}
 	return view
 }
@@ -2297,7 +2415,7 @@ func (m model) transcriptView() string {
 	if m.transcriptEmpty() && !m.pending && viewportOverlay != "" {
 		emptyOverlay = viewportOverlay
 	}
-	bodyItems := m.transcriptBodyItems(width, emptyOverlay)
+	bodyItems := m.transcriptBodyItems(width, emptyOverlay, false)
 
 	footer := m.footerView(width)
 
@@ -2337,7 +2455,7 @@ func (m model) twoColumnTranscriptView() string {
 	width := chatW
 
 	suggestionOverlay := m.suggestionOverlay(width)
-	bodyItems := m.transcriptBodyItems(width, "")
+	bodyItems := m.transcriptBodyItems(width, "", false)
 	footer := m.footerView(width)
 	overlayForViewport := suggestionOverlay
 	if m.transcriptEmpty() && !m.pending {
@@ -2767,7 +2885,15 @@ func (m model) chatTranscriptViewport() (transcriptViewport, bool) {
 		return transcriptViewport{}, false
 	}
 	width := m.chatColumnWidth()
-	items := m.transcriptBodyItems(width, "")
+	if m.transcriptDetailed {
+		items := m.transcriptBodyItems(width, "", true)
+		body := measureTranscriptBodyItems(items, m.transcriptBodyHeights)
+		header := detailedTranscriptHeader(width) + "\n" + zeroTheme.line.Render(strings.Repeat("-", width))
+		footer := m.detailedTranscriptFooter(width)
+		frame := m.scrollableTranscriptFrame(header, footer)
+		return transcriptViewportForLayout(body, frame, m.chatScrollOffset), true
+	}
+	items := m.transcriptBodyItems(width, "", false)
 	body := measureTranscriptBodyItems(items, m.transcriptBodyHeights)
 	frame := m.scrollableTranscriptFrame(m.pinnedTitleBar(width), m.footerView(width))
 	return transcriptViewportForLayout(body, frame, m.chatScrollOffset), true
@@ -3607,6 +3733,11 @@ func (m model) choosePicker() (tea.Model, tea.Cmd) {
 		if text != "" {
 			m.transcript = reduceTranscript(m.transcript, transcriptAction{kind: actionAppendSystem, text: text})
 		}
+	case pickerSkill:
+		// Fill the composer with "/name " so the user adds their request before
+		// submitting (a bare second Enter runs it without one); names the slash
+		// path cannot reach run immediately instead.
+		m, cmd = m.chooseSkillFromPicker(item)
 	case pickerTheme:
 		// The hovered palette is already live from the preview; handleThemeCommand
 		// records the choice (m.themeMode) and re-applies it, and reports the switch.
@@ -3722,6 +3853,15 @@ func (m model) handleSubmit() (tea.Model, tea.Cmd) {
 	case commandTools:
 		m.transcript = reduceTranscript(m.transcript, transcriptAction{kind: actionAppendSystem, text: m.toolsText()})
 		return m, nil
+	case commandSkills:
+		// With skills installed, /skills opens a searchable picker (like /model);
+		// the text card remains only as the no-skills install hint.
+		if picker := m.newSkillPicker(); picker != nil {
+			m.picker = picker
+			return m, nil
+		}
+		m.transcript = reduceTranscript(m.transcript, transcriptAction{kind: actionAppendSystem, text: m.skillsText()})
+		return m, nil
 	case commandMCP:
 		if strings.TrimSpace(command.text) == "" {
 			return m.openMCPManager(), nil
@@ -3917,6 +4057,11 @@ func (m model) handleSubmit() (tea.Model, tea.Cmd) {
 		if next, cmd, handled := m.handleUserCommand(command.text); handled {
 			return next, cmd
 		}
+		// Then an installed skill: "/<skill-name> [args]" runs the skill directly
+		// (deterministic invocation, vs waiting for the model to pull it in).
+		if next, cmd, handled := m.handleSkillCommand(command.text); handled {
+			return next, cmd
+		}
 		m.transcript = reduceTranscript(m.transcript, transcriptAction{
 			kind: actionAppendError,
 			text: "unknown command: " + command.text,

internal/tui/model_test.go

@@ -2142,7 +2142,7 @@ func TestTranscriptSelectionPaintsHighlightOnceNotTwice(t *testing.T) {
 	width := m.chatColumnWidth()
 
 	findRow := func(mm model) (transcriptBodyItem, bool) {
-		for _, it := range mm.transcriptBodyItems(width, "") {
+		for _, it := range mm.transcriptBodyItems(width, "", false) {
 			if it.kind == transcriptBodyItemRow && it.rowIndex >= 0 {
 				return it, true
 			}
@@ -2198,7 +2198,7 @@ func TestReasoningAfterToolCardGetsBlankSeparator(t *testing.T) {
 		transcriptRow{kind: rowReasoning, text: "Considering the next step in detail before acting"},
 		transcriptRow{kind: rowToolResult, id: "t2", tool: "read_file", status: tools.StatusOK, detail: "x\ny"},
 	)
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	reasoningIdx := -1
 	for i := range items {
 		if items[i].rowIndex >= 0 && items[i].rowIndex < len(m.transcript) &&
@@ -2223,7 +2223,7 @@ func TestAssistantNarrationBeforeToolCardGetsBlankSeparator(t *testing.T) {
 		transcriptRow{kind: rowAssistant, text: "I'll inspect the existing file, then run it."},
 		transcriptRow{kind: rowToolResult, id: "t1", tool: "read_file", status: tools.StatusOK, detail: "File: time_test.py\n\n  1 | print('x')"},
 	)
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	toolIdx := -1
 	for i := range items {
 		if items[i].rowIndex >= 0 && items[i].rowIndex < len(m.transcript) &&
@@ -2247,7 +2247,7 @@ func TestUserPromptBeforeToolCardGetsBlankSeparator(t *testing.T) {
 		transcriptRow{kind: rowUser, text: "create the landing page"},
 		transcriptRow{kind: rowToolResult, id: "t1", tool: "write_file", status: tools.StatusOK, detail: "--- /dev/null\n+++ b/index.html\n@@ -0,0 +1,1 @@\n+<!DOCTYPE html>"},
 	)
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	toolIdx := -1
 	for i := range items {
 		if items[i].rowIndex >= 0 && items[i].rowIndex < len(m.transcript) &&
@@ -2273,7 +2273,7 @@ func TestAssistantAfterToolCardGetsRuleSeparator(t *testing.T) {
 		transcriptRow{kind: rowToolResult, id: "t1", tool: "bash", status: tools.StatusOK, detail: "stdout:\nok\nexit_code: 0"},
 		transcriptRow{kind: rowAssistant, text: "Done.", final: true},
 	)
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	finalIdx := -1
 	for i := range items {
 		if items[i].rowIndex >= 0 && items[i].rowIndex < len(m.transcript) &&
@@ -2307,7 +2307,7 @@ func TestStreamingAssistantAfterToolCardGetsRuleSeparator(t *testing.T) {
 		transcriptRow{kind: rowAssistant, text: "I'll run it first."},
 		transcriptRow{kind: rowToolResult, id: "t1", tool: "bash", status: tools.StatusOK, detail: "stdout:\nok\nexit_code: 0"},
 	)
-	items := m.transcriptBodyItems(m.chatColumnWidth(), "")
+	items := m.transcriptBodyItems(m.chatColumnWidth(), "", false)
 	pendingIdx := -1
 	for i := range items {
 		if items[i].kind == transcriptBodyItemPendingInterim {
@@ -2357,7 +2357,7 @@ func TestTranscriptBodyRowsUseFullWidthAndAlignSelection(t *testing.T) {
 		t.Fatalf("expected no body gutter at width %d, got %d", width, gutter)
 	}
 
-	items := m.transcriptBodyItems(width, "")
+	items := m.transcriptBodyItems(width, "", false)
 	var row *transcriptBodyItem
 	for i := range items {
 		if items[i].kind == transcriptBodyItemRow && items[i].rowIndex >= 0 {

internal/tui/mouse.go

@@ -1,6 +1,36 @@
 package tui
 
-import tea "charm.land/bubbletea/v2"
+import (
+	"os"
+	"strings"
+	"sync"
+
+	tea "charm.land/bubbletea/v2"
+)
+
+// parseTracerPid returns true when /proc/self/status contains a non-zero
+// TracerPid. This detects any ptrace tracer (PRoot, gdb, strace, dlv, etc.),
+// not PRoot specifically. That's intentional: under any ptrace tracer the
+// AllMotion (1003) sequence is unreliable, so CellMotion is the safer
+// fallback. The only loss is hover-highlighting, which has no functional
+// impact.
+func parseTracerPid(data []byte) bool {
+	for _, line := range strings.Split(string(data), "\n") {
+		if strings.HasPrefix(line, "TracerPid:") {
+			pid := strings.TrimSpace(line[10:])
+			return pid != "0"
+		}
+	}
+	return false
+}
+
+var isRunningUnderPRoot = sync.OnceValue(func() bool {
+	data, err := os.ReadFile("/proc/self/status")
+	if err != nil {
+		return false
+	}
+	return parseTracerPid(data)
+})
 
 type mouseOverlayHit struct {
 	x int
@@ -257,7 +287,7 @@ func (m model) syncMouseCapture() (model, tea.Cmd) {
 }
 
 func (m model) mouseOverComposer(msg tea.MouseMsg) bool {
-	if !m.altScreen || m.height <= 0 {
+	if !m.altScreen || m.height <= 0 || m.transcriptDetailed {
 		return false
 	}
 	width := m.chatColumnWidth()

internal/tui/mouse_test.go

@@ -920,6 +920,30 @@ func TestMouseCaptureOnlyDuringInteractiveSetupStages(t *testing.T) {
 	}
 }
 
+// TestComposerMouseSelectionBlockedInDetailedMode: composer mouse hit-testing
+// is disabled while the detailed transcript view is active, so wheel and click
+// events in the composer area reach the transcript body instead.
+func TestComposerMouseSelectionBlockedInDetailedMode(t *testing.T) {
+	m := mouseTestModel()
+	m.input.SetValue("some text")
+
+	updated, _ := m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	if !m.transcriptDetailed {
+		t.Fatal("sanity check: Ctrl+O should enter detailed mode")
+	}
+	if !m.composerMouseSelectionBlocked() {
+		t.Fatal("composerMouseSelectionBlocked should be true in detailed mode")
+	}
+
+	width := m.chatColumnWidth()
+	frame := m.scrollableTranscriptFrame(m.pinnedTitleBar(width), m.footerView(width))
+	if m.mouseOverComposer(testMouseWheel(tea.MouseWheelUp, 0, frame.composerRect.y)) {
+		t.Fatal("mouseOverComposer should return false in detailed mode")
+	}
+}
+
 func firstTranscriptTextMouseY(t *testing.T, m model) int {
 	t.Helper()
 	_, y := firstTranscriptTextMousePoint(t, m)
@@ -986,6 +1010,38 @@ func withSidebarContent(m model) model {
 	return m
 }
 
+func TestParseTracerPidMissing(t *testing.T) {
+	if got := parseTracerPid([]byte("Pid: 123\nName: foo\n")); got {
+		t.Fatal("missing TracerPid should return false")
+	}
+}
+
+func TestParseTracerPidZero(t *testing.T) {
+	if got := parseTracerPid([]byte("TracerPid: 0\nName: foo\n")); got {
+		t.Fatal("TracerPid: 0 should return false")
+	}
+}
+
+func TestParseTracerPidNonZero(t *testing.T) {
+	if got := parseTracerPid([]byte("Name: foo\nTracerPid: 42\n")); !got {
+		t.Fatal("TracerPid: 42 should return true")
+	}
+}
+
+func TestParseTracerPidMalformed(t *testing.T) {
+	// Non-numeric values are treated as non-zero since any non-"0" string
+	// indicates a tracer is attached, matching the function's semantics.
+	if got := parseTracerPid([]byte("TracerPid: abc\n")); !got {
+		t.Fatal("malformed TracerPid should return true (non-zero string)")
+	}
+}
+
+func TestParseTracerPidEmpty(t *testing.T) {
+	if got := parseTracerPid([]byte{}); got {
+		t.Fatal("empty input should return false")
+	}
+}
+
 func setupMouseTestModel() model {
 	m := newModel(context.Background(), Options{
 		Setup: SetupOptions{

internal/tui/options.go

@@ -13,6 +13,7 @@ import (
 	"github.com/Gitlawb/zero/internal/providermodeldiscovery"
 	"github.com/Gitlawb/zero/internal/sandbox"
 	"github.com/Gitlawb/zero/internal/sessions"
+	"github.com/Gitlawb/zero/internal/skills"
 	"github.com/Gitlawb/zero/internal/tools"
 	"github.com/Gitlawb/zero/internal/usage"
 	"github.com/Gitlawb/zero/internal/zeroruntime"
@@ -48,7 +49,13 @@ type Options struct {
 	SessionCompactor            SessionCompactor
 	PrService                   *PrService
 
-	AgentOptions    agent.Options
+	AgentOptions agent.Options
+	// LoadSkills returns the installed skills (default skills dir merged with any
+	// plugin skill roots), bodies included, for /skills and direct /<skill-name>
+	// invocation. Called lazily per use so newly installed skills are picked up
+	// without a restart. Nil means the session has no skills wiring (skills stay
+	// model-pulled via the skill tool only).
+	LoadSkills      func() []skills.Skill
 	PermissionMode  agent.PermissionMode
 	ReasoningEffort modelregistry.ReasoningEffort
 	ResponseStyle   string

internal/tui/permission_prompt_test.go

@@ -309,3 +309,70 @@ func TestPermissionRenderShowsNetworkTargetAndHostScopedAlways(t *testing.T) {
 		t.Fatalf("network prompt should render target label, got %q", got)
 	}
 }
+
+// TestPermissionCursorCtrlU ensures Ctrl+U moves the permission cursor UP
+// (toward the first option). Regression: the original implementation moved
+// the cursor DOWN on Ctrl+U and UP on Ctrl+D.
+func TestPermissionCursorCtrlU(t *testing.T) {
+	m := pendingPermissionModel(t, func(agent.PermissionDecision) {})
+	m.pendingPermission.cursor = 2 // middle option
+
+	updated, _ := m.Update(testKeyCtrl('u'))
+	next := updated.(model)
+	if next.pendingPermission.cursor != 1 {
+		t.Fatalf("Ctrl+U moved cursor to %d, want 1 (one step up)", next.pendingPermission.cursor)
+	}
+}
+
+// TestPermissionCursorCtrlD ensures Ctrl+D moves the permission cursor DOWN
+// (toward the last option). Regression: the original implementation moved
+// the cursor UP on Ctrl+D and DOWN on Ctrl+U.
+func TestPermissionCursorCtrlD(t *testing.T) {
+	m := pendingPermissionModel(t, func(agent.PermissionDecision) {})
+	m.pendingPermission.cursor = 0 // first option
+
+	updated, _ := m.Update(testKeyCtrl('d'))
+	next := updated.(model)
+	if next.pendingPermission.cursor != 1 {
+		t.Fatalf("Ctrl+D moved cursor to %d, want 1 (one step down)", next.pendingPermission.cursor)
+	}
+}
+
+// TestShiftUpComposerGuard ensures Shift+Up does NOT scroll the transcript
+// when the composer has text, so it falls through to the input's own line
+// navigation.
+func TestShiftUpComposerGuard(t *testing.T) {
+	m := mouseTestModel()
+	// Add enough transcript rows so scrolling is valid.
+	for i := 0; i < 20; i++ {
+		m.transcript = appendRow(m.transcript, rowAssistant, "line")
+	}
+	m.input.SetValue("some text")
+	m.chatScrollOffset = 5
+
+	updated, cmd := m.Update(testKeyShift(tea.KeyUp))
+	next := updated.(model)
+	_ = cmd
+	if got := next.chatScrollOffset; got != 5 {
+		t.Fatalf("Shift+Up with non-empty composer scrolled offset to %d, want 5 (unchanged)", got)
+	}
+}
+
+// TestShiftDownComposerGuard ensures Shift+Down does NOT scroll the transcript
+// when the composer has text, falling through to the input's navigation.
+func TestShiftDownComposerGuard(t *testing.T) {
+	m := mouseTestModel()
+	// Add enough transcript rows so scrolling is valid.
+	for i := 0; i < 20; i++ {
+		m.transcript = appendRow(m.transcript, rowAssistant, "line")
+	}
+	m.input.SetValue("some text")
+	m.chatScrollOffset = 3
+
+	updated, cmd := m.Update(testKeyShift(tea.KeyDown))
+	next := updated.(model)
+	_ = cmd
+	if got := next.chatScrollOffset; got != 3 {
+		t.Fatalf("Shift+Down with non-empty composer scrolled offset to %d, want 3 (unchanged)", got)
+	}
+}

internal/tui/picker.go

@@ -24,6 +24,7 @@ const (
 	pickerEffort
 	pickerSession
 	pickerTheme
+	pickerSkill
 )
 
 // pickerItem is one selectable row: Label is shown, Value is passed to the
@@ -225,6 +226,35 @@ func (m model) newModelPicker() *commandPicker {
 	return &commandPicker{kind: pickerModel, title: "Choose a model", items: items, allItems: append([]pickerItem{}, items...), selected: 0}
 }
 
+// newSkillPicker lists the installed skills for browse-and-run: type to filter,
+// arrow keys to select, Enter runs the chosen skill immediately. Selection is by
+// the skill's EXACT name (item.Value), so even skills the slash path cannot
+// reach — names shadowed by a builtin or user command, or names that don't fit
+// a slash token — are runnable here: picking from the Skills picker is
+// unambiguous. Returns nil when no skills are installed (the caller falls back
+// to the install-hint card).
+func (m model) newSkillPicker() *commandPicker {
+	installed := m.installedSkills()
+	items := make([]pickerItem, 0, len(installed))
+	for _, skill := range installed {
+		name := strings.TrimSpace(skill.Name)
+		if name == "" {
+			continue
+		}
+		label := name
+		if slash := skillSlashName(name); slash != "" {
+			// Show the slash form where one exists — it doubles as documentation
+			// of the direct "/name [args]" invocation.
+			label = "/" + slash
+		}
+		items = append(items, pickerItem{Label: label, Value: name, Meta: strings.TrimSpace(skill.Description)})
+	}
+	if len(items) == 0 {
+		return nil
+	}
+	return &commandPicker{kind: pickerSkill, title: "pick a skill · ⏎ fills /name — add your request", items: items, allItems: append([]pickerItem{}, items...), selected: 0}
+}
+
 // modelPickerProviders returns the providers to list in /model: all saved
 // providers, falling back to the active profile when none were threaded in.
 func (m model) modelPickerProviders() []config.ProviderProfile {

internal/tui/rendering_lime_test.go

@@ -511,6 +511,50 @@ func TestSelectableAssistantRowKeepsMarkdownSemanticsPlain(t *testing.T) {
 	}
 }
 
+func TestStripMarkdownRenderControlsStripsAllANSI(t *testing.T) {
+	// Bold markers that renderAssistantMarkdownText embeds for prose formatting.
+	withBold := "\x1b[1mhello\x1b[22m world"
+	if got := stripMarkdownRenderControls(withBold); got != "hello world" {
+		t.Fatalf("stripMarkdownRenderControls(%q) = %q, want %q", withBold, got, "hello world")
+	}
+	// Color sequences from highlightCodeAuto for fenced code blocks.
+	withColor := "\x1b[38;2;236;236;238mdef\x1b[0m hello():"
+	if got := stripMarkdownRenderControls(withColor); got != "def hello():" {
+		t.Fatalf("stripMarkdownRenderControls(%q) = %q, want %q", withColor, got, "def hello():")
+	}
+	// Sequences that combine both (bold + underline + color).
+	withBoldColor := "\x1b[1;4;38;2;236;236;238mW\x1b[m"
+	if got := stripMarkdownRenderControls(withBoldColor); got != "W" {
+		t.Fatalf("stripMarkdownRenderControls(%q) = %q, want %q", withBoldColor, got, "W")
+	}
+}
+
+func TestSelectedTranscriptTextStripsANSIFromHighlightedCode(t *testing.T) {
+	m := limeTestModel()
+	m.width, m.height = 120, 40
+	m.altScreen = true
+	m.headerPrinted = true
+	code := `package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("hello")
+}`
+	row := transcriptRow{kind: rowAssistant, text: "First, here's the code:\n\n```go\n" + code + "\n```\n\nThat's it.", final: true}
+	m.transcript = append(m.transcript, row)
+	m.flushed = len(m.transcript)
+
+	// The highlighted code block contains ANSI color sequences from chroma;
+	// verify none survive in the selectable text used for clipboard copy.
+	_, selectable := m.renderSelectableAssistantRow(0, row, 72, 0)
+	for _, line := range selectable {
+		if ansiPattern.MatchString(line.text) {
+			t.Fatalf("selectable text leaked ANSI escapes: %q", line.text)
+		}
+	}
+}
+
 func TestFinalAnswerRendersPlainTextAndCompletionLine(t *testing.T) {
 	m := limeTestModel()
 	row := transcriptRow{

internal/tui/sidebar.go

@@ -82,7 +82,7 @@ func (m model) sidebarToggleAllowed() bool {
 // would have any visible effect. The subchat drill-in keeps its own single-column
 // view, so the sidebar is suppressed there.
 func (m model) sidebarAvailable() bool {
-	if !m.altScreen || m.height <= 0 || m.subchat.active {
+	if !m.altScreen || m.height <= 0 || m.subchat.active || m.transcriptDetailed {
 		return false
 	}
 	if sidebarWidth(m.width) <= 0 {

internal/tui/skill_commands.go

@@ -0,0 +1,205 @@
+package tui
+
+import (
+	"strings"
+
+	tea "charm.land/bubbletea/v2"
+
+	"github.com/Gitlawb/zero/internal/skills"
+)
+
+// Skill slash invocation: "/<skill-name> [args]" runs an installed skill
+// directly, mirroring user commands (.zero/commands). Skills were previously
+// model-pulled only (the skill tool), which made invocation a matter of model
+// discretion; typing the skill's name makes it deterministic. Precedence is
+// builtin > user command > skill: parseCommand resolves builtins first, and the
+// commandUnknown fallback tries user commands before skills.
+
+// handleSkillCommand resolves a "/name args" that wasn't a builtin or a user
+// command against the installed skills. On a match it launches a normal agent
+// turn whose prompt inlines the skill body (its instructions) followed by the
+// typed args, returning handled=true. handled=false means no skill matched, so
+// the caller falls through to "unknown command".
+func (m model) handleSkillCommand(raw string) (model, tea.Cmd, bool) {
+	name, args := splitUserCommand(raw)
+	if name == "" {
+		return m, nil, false
+	}
+	skill, ok := m.lookupSkillCommand(name)
+	if !ok {
+		return m, nil, false
+	}
+	body := strings.TrimSpace(skill.Content)
+	if body == "" {
+		// The name matched a real skill, so falling through to "unknown command"
+		// would mislead; surface the actual problem instead.
+		m.transcript = reduceTranscript(m.transcript, transcriptAction{
+			kind: actionAppendError,
+			text: "skill /" + name + " has an empty SKILL.md body (" + skill.Path + ")",
+		})
+		return m, nil, true
+	}
+	return m.launchOrDeferExpandedPrompt(raw, skillInvocationPrompt(body, args))
+}
+
+// bareSkillInvocationNote is appended when a skill is invoked with no request.
+// The body alone is instructions with no target ("review the PR" — which PR?),
+// and without this note the model improvises one instead of asking. The wording
+// is conditional so self-contained skills (no target needed) still just run.
+const bareSkillInvocationNote = "The user invoked this skill directly without providing a request. " +
+	"If these instructions need a target or details that are not already clear from the conversation " +
+	"(which pull request, file, branch, topic, …), ask for them first — do not guess or pick one yourself. " +
+	"If the instructions are self-contained, proceed."
+
+// skillInvocationPrompt builds the agent prompt for a skill invocation: the
+// skill body (its instructions), then either the user's request or — for a bare
+// invocation — the ask-first note above. Mirrors usercommands.Expand's
+// no-placeholder behavior for the args case.
+func skillInvocationPrompt(body, args string) string {
+	if args != "" {
+		return body + "\n\n" + args
+	}
+	return body + "\n\n" + bareSkillInvocationNote
+}
+
+// launchOrDeferExpandedPrompt applies the same run-state guards the plain
+// commandPrompt path has to an expanded (user command / skill) prompt: while
+// exiting nothing may start, a prompt submitted mid-run is queued for the next
+// turn, and compaction-in-flight warns instead of racing the compactor. The
+// EXPANDED prompt is what gets queued — the queue flush path resubmits text as
+// a literal prompt, so queuing the raw "/name args" would send it to the model
+// as prose instead of re-dispatching it. raw is the typed invocation; on the
+// compaction warning it is restored into the composer for an easy re-submit
+// (the commandUnknown dispatch cleared the composer before we got here, unlike
+// the plain-prompt path whose guard fires before the clear). Empty raw (the
+// picker path has no typed form) restores nothing.
+func (m model) launchOrDeferExpandedPrompt(raw, prompt string) (model, tea.Cmd, bool) {
+	if m.exiting {
+		return m, nil, true
+	}
+	if m.pending {
+		return m.queueMessage(prompt), nil, true
+	}
+	if m.compactInFlight {
+		if strings.TrimSpace(raw) != "" {
+			m.input.SetValue(raw)
+			m.input.CursorEnd()
+		}
+		m.transcript = reduceTranscript(m.transcript, transcriptAction{
+			kind: actionAppendSystem,
+			text: "Compact\nstatus: warning\nCompaction is running. Re-run the command when it finishes.",
+		})
+		return m, nil, true
+	}
+	next, teaCmd := m.launchPrompt(prompt)
+	return next, teaCmd, true
+}
+
+// takenSlashNames returns every slash token already claimed by a builtin
+// command (or alias) or a user command — the names a typed "/x" would dispatch
+// to before ever reaching a skill.
+func (m model) takenSlashNames() map[string]bool {
+	taken := map[string]bool{}
+	for _, command := range commandDefinitions {
+		taken[strings.TrimPrefix(command.name, "/")] = true
+		for _, alias := range command.aliases {
+			taken[strings.TrimPrefix(alias, "/")] = true
+		}
+	}
+	for _, cmd := range m.userCommands {
+		taken[cmd.Name] = true
+	}
+	return taken
+}
+
+// chooseSkillFromPicker handles Enter on a skill-picker row. Most skills want a
+// request ("review WHICH pr?"), so selection fills the composer with
+// "/name " — cursor at the end — for the user to complete and submit (Enter
+// again runs it bare). Skills whose names cannot be typed as a slash command
+// (non-slash shapes, or names shadowed by a builtin or user command) fall back
+// to running immediately: the picker is the only path that reaches them, and an
+// unfillable composer would be a dead end.
+func (m model) chooseSkillFromPicker(item pickerItem) (model, tea.Cmd) {
+	slash := skillSlashName(item.Value)
+	if slash == "" || m.takenSlashNames()[slash] {
+		return m.invokeSkillByName(item.Value)
+	}
+	m.input.SetValue("/" + slash + " ")
+	m.input.CursorEnd()
+	return m, nil
+}
+
+// invokeSkillByName runs the installed skill with the given EXACT raw name (the
+// skill-picker path). The same run-state guards as slash invocation apply; the
+// picker offers no args affordance, so the prompt is the skill body alone.
+func (m model) invokeSkillByName(name string) (model, tea.Cmd) {
+	for _, skill := range m.installedSkills() {
+		if strings.TrimSpace(skill.Name) != name {
+			continue
+		}
+		body := strings.TrimSpace(skill.Content)
+		if body == "" {
+			m.transcript = reduceTranscript(m.transcript, transcriptAction{
+				kind: actionAppendError,
+				text: "skill " + name + " has an empty SKILL.md body (" + skill.Path + ")",
+			})
+			return m, nil
+		}
+		next, teaCmd, _ := m.launchOrDeferExpandedPrompt("", skillInvocationPrompt(body, ""))
+		return next, teaCmd
+	}
+	// The picker row came from a slightly older load (TTL cache) and the skill
+	// has since been removed.
+	m.transcript = reduceTranscript(m.transcript, transcriptAction{
+		kind: actionAppendError,
+		text: "skill " + name + " is no longer installed",
+	})
+	return m, nil
+}
+
+// lookupSkillCommand returns the installed skill whose slash name matches the
+// given (lowercased) name. Linear scan over a fresh load — skills are re-read
+// per invocation so a skill installed mid-session is invocable without a
+// restart, and the body is never held on the model.
+func (m model) lookupSkillCommand(name string) (skills.Skill, bool) {
+	name = strings.ToLower(strings.TrimSpace(name))
+	if name == "" {
+		return skills.Skill{}, false
+	}
+	for _, skill := range m.installedSkills() {
+		if skillSlashName(skill.Name) == name {
+			return skill, true
+		}
+	}
+	return skills.Skill{}, false
+}
+
+// installedSkills returns the session's installed skills (default dir merged
+// with plugin skill roots) via the injected loader, or nil when the session has
+// no skills wiring (e.g. bare test models).
+func (m model) installedSkills() []skills.Skill {
+	if m.loadSkills == nil {
+		return nil
+	}
+	return m.loadSkills()
+}
+
+// skillSlashName maps a skill's frontmatter name to its slash-command form:
+// lowercased, and only if it fits the slash-token shape (letters, digits,
+// dot/underscore/hyphen — a superset of user-command names, since skill names
+// are free-form frontmatter). Returns "" for names that cannot be typed as a
+// /command (e.g. containing spaces); those skills remain loadable by the model
+// via the skill tool and are still listed by /skills.
+func skillSlashName(name string) string {
+	name = strings.ToLower(strings.TrimSpace(name))
+	if name == "" {
+		return ""
+	}
+	for _, r := range name {
+		valid := (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '-' || r == '_' || r == '.'
+		if !valid {
+			return ""
+		}
+	}
+	return name
+}

internal/tui/skill_commands_test.go

@@ -0,0 +1,412 @@
+package tui
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	tea "charm.land/bubbletea/v2"
+
+	"github.com/Gitlawb/zero/internal/agent"
+	"github.com/Gitlawb/zero/internal/skills"
+)
+
+// newSkillTestModel builds a model with an injected skills loader (and the
+// matching palette metadata), no filesystem involved.
+func newSkillTestModel(t *testing.T, installed ...skills.Skill) model {
+	t.Helper()
+	infos := make([]agent.SkillInfo, 0, len(installed))
+	for _, s := range installed {
+		infos = append(infos, agent.SkillInfo{Name: s.Name, Description: s.Description})
+	}
+	return newModel(context.Background(), Options{
+		Cwd:          t.TempDir(),
+		LoadSkills:   func() []skills.Skill { return installed },
+		AgentOptions: agent.Options{Skills: infos},
+	})
+}
+
+func submitInput(t *testing.T, m model, input string) model {
+	t.Helper()
+	m.input.SetValue(input)
+	updated, _ := m.Update(testKey(tea.KeyEnter))
+	return updated.(model)
+}
+
+func TestSkillCommandInvokesAndSubmits(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{
+		Name:        "deploy-checks",
+		Description: "Run the pre-deploy verification suite.",
+		Content:     "Run every verification step and summarize failures.",
+		Path:        "/skills/deploy-checks/SKILL.md",
+	})
+
+	next := submitInput(t, m, "/deploy-checks ship v2 to production")
+
+	if transcriptContains(next.transcript, "unknown command") {
+		t.Fatalf("an installed skill must not be 'unknown', got %#v", next.transcript)
+	}
+	if !transcriptContains(next.transcript, "Run every verification step and summarize failures.") {
+		t.Fatalf("skill body should be inlined into the prompt, got %#v", next.transcript)
+	}
+	if !transcriptContains(next.transcript, "ship v2 to production") {
+		t.Fatalf("typed args should follow the skill body, got %#v", next.transcript)
+	}
+}
+
+func TestSkillCommandWithoutArgs(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review the diff for correctness."})
+
+	next := submitInput(t, m, "/reviewer")
+
+	if !transcriptContains(next.transcript, "Review the diff for correctness.") {
+		t.Fatalf("bare skill invocation should submit the body, got %#v", next.transcript)
+	}
+	// A bare invocation carries the ask-first note: instructions with no target
+	// must make the model ask ("which PR?") instead of improvising one.
+	if !transcriptContains(next.transcript, "ask for them first") {
+		t.Fatalf("bare invocation should carry the clarify-first note, got %#v", next.transcript)
+	}
+}
+
+// An invocation WITH a request must not carry the ask-first note — the user
+// already said what to apply the skill to.
+func TestSkillCommandWithArgsHasNoClarifyNote(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review the diff."})
+
+	next := submitInput(t, m, "/reviewer PR 484 reconnect changes")
+
+	if transcriptContains(next.transcript, "ask for them first") {
+		t.Fatalf("args invocation must not carry the clarify note, got %#v", next.transcript)
+	}
+}
+
+// A skill's frontmatter name is free-form; invocation matches its lowercased
+// slash form.
+func TestSkillCommandNameIsCaseInsensitive(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "Deploy-Checks", Content: "Check things."})
+
+	next := submitInput(t, m, "/deploy-checks")
+
+	if !transcriptContains(next.transcript, "Check things.") {
+		t.Fatalf("uppercase frontmatter name should be invocable lowercased, got %#v", next.transcript)
+	}
+}
+
+// Precedence: a user command (.zero/commands) shadows a same-named skill.
+func TestUserCommandShadowsSkill(t *testing.T) {
+	root := t.TempDir()
+	writeUserCommand(t, root, "greet.md", "Say hello from the user command.")
+	m := newModel(context.Background(), Options{
+		Cwd:        root,
+		LoadSkills: func() []skills.Skill { return []skills.Skill{{Name: "greet", Content: "Skill body must not run."}} },
+	})
+
+	next := submitInput(t, m, "/greet")
+
+	if !transcriptContains(next.transcript, "Say hello from the user command.") {
+		t.Fatalf("user command should win the name collision, got %#v", next.transcript)
+	}
+	if transcriptContains(next.transcript, "Skill body must not run.") {
+		t.Fatalf("shadowed skill must not run, got %#v", next.transcript)
+	}
+}
+
+// An empty skill body is a real, named match — surface the problem instead of
+// falling through to a misleading "unknown command".
+func TestSkillCommandEmptyBody(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "hollow", Path: "/skills/hollow/SKILL.md"})
+
+	next := submitInput(t, m, "/hollow")
+
+	if transcriptContains(next.transcript, "unknown command") {
+		t.Fatalf("an empty skill must not be 'unknown', got %#v", next.transcript)
+	}
+	if !transcriptContains(next.transcript, "empty SKILL.md body") {
+		t.Fatalf("empty-body error should be surfaced, got %#v", next.transcript)
+	}
+}
+
+func TestUnknownSlashStillUnknownWithSkillsInstalled(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review."})
+
+	next := submitInput(t, m, "/definitelynotaskill")
+
+	if !transcriptContains(next.transcript, "unknown command") {
+		t.Fatalf("non-matching name should still be unknown, got %#v", next.transcript)
+	}
+}
+
+func TestSkillSlashName(t *testing.T) {
+	cases := map[string]string{
+		"deploy-checks":  "deploy-checks",
+		"Deploy-Checks":  "deploy-checks",
+		"  pdf_tools  ":  "pdf_tools",
+		"v2.migrate":     "v2.migrate",
+		"has space":      "",
+		"emoji✨":         "",
+		"":               "",
+		"slash/inside":   "",
+		"tab\tseparated": "",
+	}
+	for in, want := range cases {
+		if got := skillSlashName(in); got != want {
+			t.Errorf("skillSlashName(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
+
+func TestSkillAppearsInAutocomplete(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "deploy-checks", Description: "Run the pre-deploy suite.", Content: "x"})
+
+	got := m.matchCommandSuggestions("/dep")
+	found := false
+	for _, s := range got {
+		if s.Name == "/deploy-checks" {
+			found = true
+			if s.Desc != "Run the pre-deploy suite. (skill)" {
+				t.Fatalf("skill suggestion should be labeled, got %q", s.Desc)
+			}
+		}
+	}
+	if !found {
+		t.Fatalf("skill /deploy-checks should appear for '/dep', got %#v", got)
+	}
+}
+
+// A skill shadowed by a builtin (or its alias) or a user command would be dead
+// at dispatch time, so the palette must not advertise it.
+func TestShadowedSkillNotSuggested(t *testing.T) {
+	root := t.TempDir()
+	writeUserCommand(t, root, "deploy.md", "User deploy.")
+	installed := []skills.Skill{
+		{Name: "help", Content: "x"},     // builtin collision
+		{Name: "sessions", Content: "x"}, // builtin ALIAS collision (/resume alias)
+		{Name: "deploy", Content: "x"},   // user-command collision
+	}
+	infos := make([]agent.SkillInfo, 0, len(installed))
+	for _, s := range installed {
+		infos = append(infos, agent.SkillInfo{Name: s.Name})
+	}
+	m := newModel(context.Background(), Options{
+		Cwd:          root,
+		LoadSkills:   func() []skills.Skill { return installed },
+		AgentOptions: agent.Options{Skills: infos},
+	})
+
+	// Assert on the advertised NAME with a skill-marked Desc, not on the exact
+	// fallback Desc format — the invariant is that no skill row carries a
+	// builtin/user-command name, regardless of description wording.
+	for _, token := range []string{"/hel", "/ses", "/dep"} {
+		for _, s := range m.matchSkillSuggestions(token) {
+			if s.Name == "/help" || s.Name == "/sessions" || s.Name == "/deploy" {
+				t.Fatalf("shadowed skill advertised for %q: %#v", token, s)
+			}
+		}
+	}
+}
+
+// Invalid slash shapes (spaces etc.) and a bare "/" must not surface skills.
+func TestSkillSuggestionEdgeCases(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "has space", Description: "not invocable", Content: "x"})
+
+	if got := m.matchSkillSuggestions("/has"); len(got) != 0 {
+		t.Fatalf("invalid slash-shape skill must not be suggested, got %#v", got)
+	}
+	if got := m.matchSkillSuggestions("/"); got != nil {
+		t.Fatalf("bare '/' should not list skills, got %#v", got)
+	}
+}
+
+func TestSkillsCommandResolves(t *testing.T) {
+	command, ok := resolveCommand("/skills")
+	if !ok || command.kind != commandSkills {
+		t.Fatalf("resolveCommand(/skills) = %#v, %v", command, ok)
+	}
+}
+
+// With skills installed, /skills opens a searchable picker (like /model).
+func TestSkillsCommandOpensPicker(t *testing.T) {
+	m := newSkillTestModel(t,
+		skills.Skill{Name: "deploy-checks", Description: "Run the pre-deploy suite.", Content: "x"},
+		skills.Skill{Name: "has space", Description: "tool-only skill", Content: "x"},
+	)
+
+	next := submitInput(t, m, "/skills")
+
+	if next.picker == nil || next.picker.kind != pickerSkill {
+		t.Fatalf("/skills should open the skill picker, got %#v", next.picker)
+	}
+	labels := map[string]string{}
+	for _, item := range next.picker.items {
+		labels[item.Label] = item.Value
+	}
+	if labels["/deploy-checks"] != "deploy-checks" {
+		t.Fatalf("slash-invocable skill should show its slash form, got %#v", labels)
+	}
+	// A non-slash-shaped name is still selectable (bare label, exact-name value).
+	if labels["has space"] != "has space" {
+		t.Fatalf("non-slash skill should be listed bare but selectable, got %#v", labels)
+	}
+}
+
+// Enter on a picker row fills the composer with "/name " so the user can add
+// their request (which PR? which file?) before submitting — it must NOT fire
+// the skill with no request attached.
+func TestSkillPickerEnterFillsComposer(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review the diff for correctness."})
+
+	next := submitInput(t, m, "/skills")
+	if next.picker == nil {
+		t.Fatal("picker should be open")
+	}
+	updated, _ := next.Update(testKey(tea.KeyEnter))
+	after := updated.(model)
+
+	if after.picker != nil {
+		t.Fatal("picker should close on Enter")
+	}
+	if got := after.input.Value(); got != "/reviewer " {
+		t.Fatalf("composer should be filled with the invocation, got %q", got)
+	}
+	if transcriptContains(after.transcript, "Review the diff for correctness.") {
+		t.Fatalf("skill must not run before the user submits, got %#v", after.transcript)
+	}
+
+	// A second Enter submits the (bare) invocation and runs the skill.
+	final, _ := after.Update(testKey(tea.KeyEnter))
+	done := final.(model)
+	if !transcriptContains(done.transcript, "Review the diff for correctness.") {
+		t.Fatalf("submitting the filled composer should run the skill, got %#v", done.transcript)
+	}
+}
+
+// Picker selection is by exact name, so a skill shadowed by a builtin (dead on
+// the slash path) is still runnable from the picker.
+func TestSkillPickerRunsBuiltinShadowedSkill(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "help", Description: "shadowed", Content: "Shadowed skill body."})
+
+	next := submitInput(t, m, "/skills")
+	if next.picker == nil {
+		t.Fatal("picker should be open")
+	}
+	updated, _ := next.Update(testKey(tea.KeyEnter))
+	after := updated.(model)
+
+	if !transcriptContains(after.transcript, "Shadowed skill body.") {
+		t.Fatalf("picker must run the shadowed skill directly, got %#v", after.transcript)
+	}
+}
+
+func TestSkillsCommandEmptyState(t *testing.T) {
+	m := newModel(context.Background(), Options{Cwd: t.TempDir()})
+
+	next := submitInput(t, m, "/skills")
+
+	if !transcriptContains(next.transcript, "No skills installed.") {
+		t.Fatalf("empty state should say no skills, got %#v", next.transcript)
+	}
+}
+
+// Run-state guards: an expanded skill prompt must not race an active run — it
+// queues (as the EXPANDED prompt, since the queue flush submits literal text).
+func TestSkillInvocationQueuedWhileRunPending(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review the diff."})
+	m.pending = true
+
+	next, _, handled := m.handleSkillCommand("/reviewer focus on tests")
+	if !handled {
+		t.Fatal("skill must be handled even while a run is pending")
+	}
+	if next.queuedMessage == "" || !strings.Contains(next.queuedMessage, "Review the diff.") {
+		t.Fatalf("expanded prompt should be queued, got %q", next.queuedMessage)
+	}
+	if !strings.Contains(next.queuedMessage, "focus on tests") {
+		t.Fatalf("queued prompt should carry the args, got %q", next.queuedMessage)
+	}
+}
+
+func TestSkillInvocationDroppedWhileExiting(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review."})
+	m.exiting = true
+
+	next, cmd, handled := m.handleSkillCommand("/reviewer")
+	if !handled || cmd != nil || next.queuedMessage != "" {
+		t.Fatalf("exiting must swallow the invocation: handled=%v cmd=%v queued=%q", handled, cmd, next.queuedMessage)
+	}
+}
+
+func TestSkillInvocationWarnsDuringCompaction(t *testing.T) {
+	m := newSkillTestModel(t, skills.Skill{Name: "reviewer", Content: "Review."})
+	m.compactInFlight = true
+
+	next, _, handled := m.handleSkillCommand("/reviewer")
+	if !handled {
+		t.Fatal("skill must be handled during compaction")
+	}
+	if !transcriptContains(next.transcript, "Compaction is running") {
+		t.Fatalf("compaction warning expected, got %#v", next.transcript)
+	}
+	// The typed invocation is restored for an easy re-submit (the dispatch path
+	// cleared the composer before the guard could fire).
+	if got := next.input.Value(); got != "/reviewer" {
+		t.Fatalf("typed invocation should be restored into the composer, got %q", got)
+	}
+}
+
+// The same guard now protects user commands (previously they could start a
+// second concurrent run).
+func TestUserCommandQueuedWhileRunPending(t *testing.T) {
+	root := t.TempDir()
+	writeUserCommand(t, root, "greet.md", "Say hello to $1.")
+	m := newModel(context.Background(), Options{Cwd: root})
+	m.pending = true
+
+	next, _, handled := m.handleUserCommand("/greet world")
+	if !handled {
+		t.Fatal("user command must be handled while pending")
+	}
+	if !strings.Contains(next.queuedMessage, "Say hello to world.") {
+		t.Fatalf("expanded user-command prompt should be queued, got %q", next.queuedMessage)
+	}
+}
+
+// Two skills whose names collide after lowercasing map to one slash name; only
+// the one dispatch will run may be advertised.
+func TestCaseCollidingSkillsAdvertisedOnce(t *testing.T) {
+	m := newSkillTestModel(t,
+		skills.Skill{Name: "Deploy", Description: "wins", Content: "a"},
+		skills.Skill{Name: "deploy", Description: "loses", Content: "b"},
+	)
+
+	rows := 0
+	for _, s := range m.matchSkillSuggestions("/dep") {
+		if s.Name == "/deploy" {
+			rows++
+			if !strings.Contains(s.Desc, "wins") {
+				t.Fatalf("advertised row must describe the skill dispatch runs, got %q", s.Desc)
+			}
+		}
+	}
+	if rows != 1 {
+		t.Fatalf("case-colliding skills must yield exactly one /deploy row, got %d", rows)
+	}
+}
+
+// The palette reads through the loader, so a skill installed mid-session (the
+// loader's next result) appears without a restart.
+func TestSkillPaletteReadsThroughLoader(t *testing.T) {
+	installed := []skills.Skill{}
+	m := newModel(context.Background(), Options{
+		Cwd:        t.TempDir(),
+		LoadSkills: func() []skills.Skill { return installed },
+	})
+	if got := m.matchSkillSuggestions("/lat"); len(got) != 0 {
+		t.Fatalf("no skills installed yet, got %#v", got)
+	}
+	installed = append(installed, skills.Skill{Name: "late-arrival", Description: "installed mid-session", Content: "x"})
+	got := m.matchSkillSuggestions("/lat")
+	if len(got) != 1 || got[0].Name != "/late-arrival" {
+		t.Fatalf("mid-session skill should appear via the loader, got %#v", got)
+	}
+}

internal/tui/specialist_summary_render_test.go

@@ -22,7 +22,7 @@ func TestTranscriptBodyItemsIncludesSummaryBeforeCards(t *testing.T) {
 		specialistInfo: &specialistInfo{name: "explorer", description: "map code", childSessionID: "s2", status: specialistCompleted, startedAt: now, completedAt: now, tokenCount: 2000},
 	})
 
-	items := m.transcriptBodyItems(80, "")
+	items := m.transcriptBodyItems(80, "", false)
 	body := bodyItemsString(m, items, 80)
 	if !strings.Contains(body, "specialists") {
 		t.Errorf("transcript body should contain summary line with 'specialists', got:\n%s", body)

internal/tui/transcript_body_test.go

@@ -6,7 +6,7 @@ func TestTranscriptBodyItemsRepresentEmptyState(t *testing.T) {
 	m := mouseTestModel()
 	width := m.chatColumnWidth()
 
-	items := m.transcriptBodyItems(width, "")
+	items := m.transcriptBodyItems(width, "", false)
 	layout := layoutTranscriptBodyItems(items)
 
 	if len(layout.spans) != 1 || layout.spans[0].kind != transcriptBodyItemEmpty {
@@ -25,7 +25,7 @@ func TestTranscriptBodyItemsShiftSelectableLinesByItemStart(t *testing.T) {
 	m.transcript = appendRow(m.transcript, rowUser, "hello")
 	width := m.chatColumnWidth()
 
-	layout := layoutTranscriptBodyItems(m.transcriptBodyItems(width, ""))
+	layout := layoutTranscriptBodyItems(m.transcriptBodyItems(width, "", false))
 
 	if len(layout.spans) != 1 || layout.spans[0].kind != transcriptBodyItemRow {
 		t.Fatalf("spans = %#v, want one transcript row item", layout.spans)
@@ -51,7 +51,7 @@ func TestTranscriptBodyItemsKeepPendingInterimSelectableLocal(t *testing.T) {
 	m.streamingReasoning = "private thought"
 	width := m.chatColumnWidth()
 
-	layout := layoutTranscriptBodyItems(m.transcriptBodyItems(width, ""))
+	layout := layoutTranscriptBodyItems(m.transcriptBodyItems(width, "", false))
 
 	if len(layout.spans) != 2 {
 		t.Fatalf("spans = %#v, want separator plus pending interim", layout.spans)
@@ -181,7 +181,7 @@ func TestScrollableTranscriptItemsViewMatchesFullLayout(t *testing.T) {
 	width := m.chatColumnWidth()
 	header := m.pinnedTitleBar(width)
 	footer := m.footerView(width)
-	items := m.transcriptBodyItems(width, "")
+	items := m.transcriptBodyItems(width, "", false)
 	full := layoutTranscriptBodyItems(items)
 
 	got := m.scrollableTranscriptItemsView(header, items, footer, width, "")

internal/tui/transcript_selection.go

@@ -107,7 +107,7 @@ type transcriptBodyLayout struct {
 }
 
 func (m model) transcriptBodyLayout(width int, emptyOverlay string) transcriptBodyLayout {
-	return layoutTranscriptBodyItems(m.transcriptBodyItems(width, emptyOverlay))
+	return layoutTranscriptBodyItems(m.transcriptBodyItems(width, emptyOverlay, false))
 }
 
 func (m model) transcriptBody(width int, emptyOverlay string) (string, []transcriptSelectableLine) {
@@ -210,7 +210,7 @@ func (m model) renderHoverHighlight(rendered string, selectable []transcriptSele
 	return strings.Join(lines, "\n")
 }
 
-func (m model) transcriptBodyItems(width int, emptyOverlay string) []transcriptBodyItem {
+func (m model) transcriptBodyItems(width int, emptyOverlay string, detailed bool) []transcriptBodyItem {
 	// File drill-in: the chat column's body swaps to the viewed file's
 	// diff/content. Swapping HERE (the single source every consumer reads) keeps
 	// the viewport, scroll engine, renderer, and mouse hit-tests consistent.
@@ -241,9 +241,19 @@ func (m model) transcriptBodyItems(width int, emptyOverlay string) []transcriptB
 	} else {
 		rc := buildRowContext(m.transcript)
 		shownAny := false
-		previousKind, havePreviousKind = previousVisibleTranscriptKind(m.transcript, m.flushed, rc)
+		// The detailed view shows the full transcript from index 0, not
+		// the managed region after m.flushed.
+		startIdx := m.flushed
+		if detailed {
+			startIdx = 0
+		}
+		renderRowFn := transcriptRowDispatchFn(m.renderTranscriptRow)
+		if detailed {
+			renderRowFn = transcriptRowDispatchFn(m.renderTranscriptDetailedRow)
+		}
+		previousKind, havePreviousKind = previousVisibleTranscriptKind(m.transcript, startIdx, rc)
 		specialistSummaryEmitted := false
-		for index := m.flushed; index < len(m.transcript); index++ {
+		for index := startIdx; index < len(m.transcript); index++ {
 			row := m.transcript[index]
 			// A welcome row carries no Lime visual (the empty state replaced it)
 			// and a resolved tool call collapses into its result's card.
@@ -344,16 +354,18 @@ func (m model) transcriptBodyItems(width int, emptyOverlay string) []transcriptB
 				}
 			}
 			rowIndex, transcriptRow := index, row
-			// Key the height cache on contentWidth (the wrap width drives line count);
-			// the gutter is a horizontal-only post-pad and never changes height.
-			heightCacheKey, heightCacheStable := m.transcriptRowBodyHeightCacheKey(transcriptRow, contentWidth, rc)
+			bodyCap := cardBodyMaxLines
+			if detailed {
+				bodyCap = 0
+			}
+			heightCacheKey, heightCacheStable := m.transcriptRowBodyHeightCacheKeyOpts(transcriptRow, contentWidth, rc, bodyCap)
 			items = append(items, transcriptBodyItem{
 				kind:              transcriptBodyItemRow,
 				rowIndex:          rowIndex,
 				heightCacheKey:    heightCacheKey,
 				heightCacheStable: heightCacheStable,
 				render: func(startBodyY int) transcriptBodyRenderedItem {
-					rendered, selectable := m.renderTranscriptRow(rowIndex, transcriptRow, contentWidth, rc, startBodyY)
+					rendered, selectable := renderRowFn(rowIndex, transcriptRow, contentWidth, rc, startBodyY)
 					return m.finalizeTranscriptBodyRow(rendered, selectable, gutter, startBodyY)
 				},
 			})
@@ -635,8 +647,17 @@ func transcriptBlockBodyHeightCacheKey(kind transcriptBodyItemKind, block string
 	return b.String()
 }
 
-func (m model) transcriptRowBodyHeightCacheKey(row transcriptRow, width int, rc rowContext) (string, bool) {
-	opts := cardRenderOptions{bodyCap: cardBodyMaxLines, cwd: m.cwd}
+// rowRenderFn abstracts row rendering for normal vs detailed mode:
+// m.renderRow for normal (bodyCap: cardBodyMaxLines) and m.renderRowDetailed
+// for detailed (bodyCap: 0).
+type rowRenderFn func(transcriptRow, int, rowContext) string
+
+// transcriptRowDispatchFn dispatches row-kind rendering for the transcript body
+// pipeline, producing rendered text and selectable-line geometry.
+type transcriptRowDispatchFn func(int, transcriptRow, int, rowContext, int) (string, []transcriptSelectableLine)
+
+func (m model) transcriptRowBodyHeightCacheKeyOpts(row transcriptRow, width int, rc rowContext, bodyCap int) (string, bool) {
+	opts := cardRenderOptions{bodyCap: bodyCap, cwd: m.cwd}
 	rowKey, stable := m.renderRowCacheKey(row, width, rc, opts, false)
 	if rowKey == "" {
 		return "", false
@@ -648,6 +669,17 @@ func (m model) transcriptRowBodyHeightCacheKey(row transcriptRow, width int, rc
 }
 
 func (m model) renderTranscriptRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
+	return m.renderTranscriptRowFn(rowIndex, row, width, rc, startBodyY, m.renderRow)
+}
+
+// renderTranscriptDetailedRow routes through renderTranscriptRowFn with
+// renderRowDetailed (bodyCap: 0) so tool output appears uncapped.
+func (m model) renderTranscriptDetailedRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
+	return m.renderTranscriptRowFn(rowIndex, row, width, rc, startBodyY, m.renderRowDetailed)
+}
+
+// renderTranscriptRowFn dispatches row-kind rendering using the provided renderFn.
+func (m model) renderTranscriptRowFn(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int, renderFn rowRenderFn) (string, []transcriptSelectableLine) {
 	switch row.kind {
 	case rowUser:
 		return m.renderSelectableUserRow(rowIndex, row, width, startBodyY)
@@ -656,21 +688,26 @@ func (m model) renderTranscriptRow(rowIndex int, row transcriptRow, width int, r
 	case rowReasoning:
 		return m.renderSelectableReasoningRow(rowIndex, row, width, startBodyY)
 	case rowSystem, rowError, rowToolCall, rowPermission, rowAskUser:
-		return m.renderSelectableRenderedRow(rowIndex, row, width, rc, startBodyY)
+		return m.renderSelectableRenderedRowFn(rowIndex, row, width, rc, startBodyY, renderFn)
 	case rowToolResult:
-		return m.renderSelectableToolResultRow(rowIndex, row, width, rc, startBodyY)
+		return m.renderSelectableToolResultRowFn(rowIndex, row, width, rc, startBodyY, renderFn)
 	case rowSpecialist:
-		return m.renderSelectableSpecialistRow(rowIndex, row, width, rc, startBodyY)
+		return m.renderSelectableSpecialistRowFn(rowIndex, row, width, rc, startBodyY, renderFn)
 	default:
-		return m.renderRow(row, width, rc), nil
+		rendered := renderFn(row, width, rc)
+		if rendered == "" {
+			return "", nil
+		}
+		selectable := selectableLinesFromRendered(rowIndex, rendered, startBodyY, 0)
+		return rendered, selectable
 	}
 }
 
 // renderSelectableToolResultRow renders the tool result card and marks its head
 // (first line) as a clickable collapse/expand toggle. Body/footer text remains
 // selectable so copying a visible transcript range includes command output.
-func (m model) renderSelectableToolResultRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
-	rendered := m.renderRow(row, width, rc)
+func (m model) renderSelectableToolResultRowFn(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int, renderFn rowRenderFn) (string, []transcriptSelectableLine) {
+	rendered := renderFn(row, width, rc)
 	if rendered == "" {
 		return "", nil
 	}
@@ -694,8 +731,12 @@ func (m model) renderSelectableToolResultRow(rowIndex int, row transcriptRow, wi
 	return rendered, selectable
 }
 
-func (m model) renderSelectableRenderedRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
-	rendered := m.renderRow(row, width, rc)
+func (m model) renderSelectableToolResultRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
+	return m.renderSelectableToolResultRowFn(rowIndex, row, width, rc, startBodyY, m.renderRow)
+}
+
+func (m model) renderSelectableRenderedRowFn(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int, renderFn rowRenderFn) (string, []transcriptSelectableLine) {
+	rendered := renderFn(row, width, rc)
 	if rendered == "" {
 		return "", nil
 	}
@@ -828,11 +869,8 @@ func (m model) renderTranscriptSelectableStyledLine(line transcriptSelectableLin
 	return prefix + zeroTheme.selection.Render(selected) + suffix
 }
 
-// renderSelectableSpecialistRow renders a specialist card and marks every line
-// as a clickable specialistCard selectable line carrying the childSessionID.
-// A left-click or Enter on any card line drills into that specialist's subchat.
-func (m model) renderSelectableSpecialistRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
-	rendered := m.renderRow(row, width, rc)
+func (m model) renderSelectableSpecialistRowFn(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int, renderFn rowRenderFn) (string, []transcriptSelectableLine) {
+	rendered := renderFn(row, width, rc)
 	if rendered == "" || row.specialistInfo == nil {
 		return "", nil
 	}
@@ -846,9 +884,6 @@ func (m model) renderSelectableSpecialistRow(rowIndex int, row transcriptRow, wi
 			specialistCard: true,
 			specialistID:   row.specialistInfo.childSessionID,
 		}
-		// Carry the line's plain text + start so a selection dragged THROUGH the
-		// card copies its content; the specialistCard flag still makes a direct
-		// click drill into the sub-session (handled on press, before selection).
 		if meta, ok := selectableLineFromRenderedLine(rowIndex, startBodyY+i, lines[i], boxed); ok {
 			sl.text = meta.text
 			sl.textStart = meta.textStart
@@ -858,6 +893,13 @@ func (m model) renderSelectableSpecialistRow(rowIndex int, row transcriptRow, wi
 	return rendered, selectable
 }
 
+// renderSelectableSpecialistRow renders a specialist card and marks every line
+// as a clickable specialistCard selectable line carrying the childSessionID.
+// A left-click or Enter on any card line drills into that specialist's subchat.
+func (m model) renderSelectableSpecialistRow(rowIndex int, row transcriptRow, width int, rc rowContext, startBodyY int) (string, []transcriptSelectableLine) {
+	return m.renderSelectableSpecialistRowFn(rowIndex, row, width, rc, startBodyY, m.renderRow)
+}
+
 func (m model) renderSelectableUserRow(rowIndex int, row transcriptRow, width int, startBodyY int) (string, []transcriptSelectableLine) {
 	contentWidth := userPromptContentWidth(width)
 	wrapped := wrapPlainText(row.text, maxInt(1, contentWidth))
@@ -1030,12 +1072,18 @@ func splitPlainAtDisplayWidth(text string, width int) (string, string) {
 // selection previously resolved against transcript rows that weren't even
 // visible while viewing a subagent/swarm child session.
 func (m model) transcriptHitTestSource() (header string, items []transcriptBodyItem, width int) {
+	if m.transcriptDetailed {
+		width = chatWidth(m.width)
+		header = detailedTranscriptHeader(width) + "\n" + zeroTheme.line.Render(strings.Repeat("-", width))
+		items = m.transcriptBodyItems(width, "", true)
+		return
+	}
 	if m.subchat.active {
 		width = chatWidth(m.width)
 		return renderSubchatNavBar(m.subchat.childSessionTitle, width), m.transcriptBodyItemsFromRows(m.subchat.childRows, width), width
 	}
 	width = m.chatColumnWidth()
-	return m.pinnedTitleBar(width), m.transcriptBodyItems(width, ""), width
+	return m.pinnedTitleBar(width), m.transcriptBodyItems(width, "", false), width
 }
 
 // transcriptHitTestBlocked reports whether mouse hit-testing must be skipped
@@ -1049,7 +1097,11 @@ func (m model) transcriptHitTestBlocked() bool {
 // (nearest-line fallback for scroll-driven selection extension).
 func (m model) transcriptHitTestLayout() (frame transcriptFrameLayout, window transcriptViewportWindow, layout transcriptBodyLayout) {
 	header, items, width := m.transcriptHitTestSource()
-	frame = m.scrollableTranscriptFrame(header, m.footerView(width))
+	footer := m.footerView(width)
+	if m.transcriptDetailed {
+		footer = m.detailedTranscriptFooter(width)
+	}
+	frame = m.scrollableTranscriptFrame(header, footer)
 	metrics := measureTranscriptBodyItems(items, m.transcriptBodyHeights)
 	window = transcriptViewportForLayout(metrics, frame, m.chatScrollOffset).window()
 	layout = layoutVisibleTranscriptBodyItems(items, metrics, window)

internal/tui/transcript_view.go

@@ -1,10 +1,16 @@
 package tui
 
-import "strings"
+import (
+	"fmt"
+	"strings"
+)
 
 func (m model) toggleDetailedTranscript() model {
 	m.transcriptDetailed = !m.transcriptDetailed
 	m.clearSuggestions()
+	if m.fileView.active {
+		m = m.exitFileView()
+	}
 	if m.picker != nil && m.picker.kind == pickerTheme {
 		// Dropping a theme picker mid-preview must undo the live palette, or the
 		// previewed theme would stick while m.themeMode still holds the old one.
@@ -14,55 +20,36 @@ func (m model) toggleDetailedTranscript() model {
 	return m
 }
 
+// detailedTranscriptView renders the full (uncapped) transcript viewport.
+// Tool output that would be truncated in the live view appears in full here.
 func (m model) detailedTranscriptView() string {
 	width := chatWidth(m.width)
-	rc := buildRowContext(m.transcript)
-	renderer := m
-	renderer.pending = false
-	renderer.activeRunID = 0
+	items := m.transcriptBodyItems(width, "", true)
 
-	var builder strings.Builder
-	builder.WriteString(detailedTranscriptHeader(width))
-	builder.WriteString("\n")
-	builder.WriteString(zeroTheme.line.Render(strings.Repeat("-", width)))
-	builder.WriteString("\n")
+	header := detailedTranscriptHeader(width) + "\n" + zeroTheme.line.Render(strings.Repeat("-", width))
+	footer := m.detailedTranscriptFooter(width)
 
-	shownAny := false
-	var previousKind rowKind
-	for _, row := range m.transcript {
-		if rc.skip(row) {
-			continue
-		}
-		rendered := ""
-		if row.kind == rowWelcome {
-			rendered = fitStyledLine(zeroTheme.faint.Render(row.text), width)
-		} else {
-			rendered = renderer.renderRowDetailed(row, width, rc)
-		}
-		if rendered == "" {
-			continue
-		}
-		if shownAny && startsTurn(row.kind) {
-			builder.WriteString("\n")
-		}
-		if shownAny && previousKind == rowUser && row.kind == rowReasoning {
-			builder.WriteString("\n")
-		}
-		builder.WriteString(rendered)
-		builder.WriteString("\n")
-		shownAny = true
-		previousKind = row.kind
+	if m.altScreen && m.height > 0 {
+		return m.scrollableTranscriptItemsView(header, items, footer, width, "")
+	}
+	// Popup/fallback: render the full body without viewport clipping.
+	layout := layoutTranscriptBodyItems(items)
+	return header + "\n" + layout.String() + "\n" + footer
+}
+
+// detailedTranscriptFooter builds the one-line footer for the detailed transcript
+// view: copy status when active, otherwise the key hint with jump-to-bottom cue.
+func (m model) detailedTranscriptFooter(width int) string {
+	if copyStatus := strings.TrimSpace(m.copyStatus); copyStatus != "" {
+		return rightAlignedLine(zeroTheme.ink.Render(copyStatus), width)
 	}
 
-	if !shownAny {
-		builder.WriteString(zeroTheme.faint.Render("No transcript rows."))
-		builder.WriteString("\n")
+	detailKey := labelOr(m.keyBindings.toggleDetailed, "Ctrl+O")
+	hint := zeroTheme.faint.Render(fmt.Sprintf("Esc close | %s toggle", detailKey))
+	if jt := m.jumpToBottomHint(); jt != "" {
+		return fitStyledLine(joinHeaderLine(hint, jt, width), width)
 	}
-
-	builder.WriteString(zeroTheme.line.Render(strings.Repeat("-", width)))
-	builder.WriteString("\n")
-	builder.WriteString(fitStyledLine(zeroTheme.faint.Render("Esc close | Ctrl+O toggle"), width))
-	return builder.String()
+	return fitStyledLine(hint, width)
 }
 
 func detailedTranscriptHeader(width int) string {

internal/tui/transcript_view_test.go

@@ -124,6 +124,78 @@ func transcriptViewTestModel() model {
 	return m
 }
 
+func TestPgUpDownScrollsDetailedTranscript(t *testing.T) {
+	m := transcriptViewTestModel()
+	m.altScreen = true
+	// Fill the transcript enough to overflow the 30-row viewport.
+	for i := 0; i < 60; i++ {
+		m.transcript = append(m.transcript, transcriptRow{kind: rowUser, text: "line content", final: true})
+	}
+	m.flushed = len(m.transcript)
+
+	// Enter detailed mode.
+	updated, _ := m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	if !m.transcriptDetailed {
+		t.Fatal("sanity check failed: Ctrl+O should enter detailed mode")
+	}
+	if m.chatScrollOffset != 0 {
+		t.Fatal("sanity check failed: detailed transcript should start at bottom")
+	}
+
+	// PgUp reveals older content = positive scroll offset.
+	updated, _ = m.Update(testKey(tea.KeyPgUp))
+	m = updated.(model)
+	if m.chatScrollOffset <= 0 {
+		t.Fatalf("PgUp in detailed mode should scroll toward older content, got chatScrollOffset=%d", m.chatScrollOffset)
+	}
+
+	// PgDown scrolls back toward bottom.
+	updated, _ = m.Update(testKey(tea.KeyPgDown))
+	m = updated.(model)
+	if m.chatScrollOffset != 0 {
+		t.Fatalf("PgDown after PgUp should return to bottom in detailed mode, got chatScrollOffset=%d", m.chatScrollOffset)
+	}
+}
+
+func TestUpDownArrowsScrollDetailedTranscript(t *testing.T) {
+	m := transcriptViewTestModel()
+	m.altScreen = true
+	for i := 0; i < 60; i++ {
+		m.transcript = append(m.transcript, transcriptRow{kind: rowUser, text: "line content", final: true})
+	}
+	m.flushed = len(m.transcript)
+
+	updated, _ := m.Update(testKeyCtrl('o'))
+	m = updated.(model)
+
+	if !m.transcriptDetailed {
+		t.Fatal("sanity check failed: Ctrl+O should enter detailed mode")
+	}
+
+	// Arrow down scrolls one line toward newer content; at bottom it stays at 0.
+	updated, _ = m.Update(testKey(tea.KeyDown))
+	m = updated.(model)
+	if m.chatScrollOffset != 0 {
+		t.Fatalf("KeyDown at bottom should stay at 0, got %d", m.chatScrollOffset)
+	}
+
+	// Arrow up scrolls one line toward older content.
+	updated, _ = m.Update(testKey(tea.KeyUp))
+	m = updated.(model)
+	if m.chatScrollOffset != 1 {
+		t.Fatalf("KeyUp should scroll one line up, got chatScrollOffset=%d", m.chatScrollOffset)
+	}
+
+	// Arrow down scrolls back toward bottom.
+	updated, _ = m.Update(testKey(tea.KeyDown))
+	m = updated.(model)
+	if m.chatScrollOffset != 0 {
+		t.Fatalf("KeyDown after KeyUp should return to bottom, got chatScrollOffset=%d", m.chatScrollOffset)
+	}
+}
+
 func numberedLines(count int) string {
 	lines := make([]string, 0, count)
 	for i := 1; i <= count; i++ {

internal/tui/user_commands.go

@@ -30,8 +30,9 @@ func (m model) handleUserCommand(raw string) (model, tea.Cmd, bool) {
 	if strings.TrimSpace(prompt) == "" {
 		return m, nil, false
 	}
-	next, teaCmd := m.launchPrompt(prompt)
-	return next, teaCmd, true
+	// Same run-state guards as a plain prompt: a user command invoked mid-run is
+	// queued (as its expanded prompt), not raced into a second concurrent turn.
+	return m.launchOrDeferExpandedPrompt(raw, prompt)
 }
 
 // lookupUserCommand returns the loaded user command with the given (lowercased)

internal/zeroruntime/types.go

@@ -203,6 +203,13 @@ type CompletionRequest struct {
 	// Anthropic/Gemini thinking budgets) and ignores it for models that do not
 	// support reasoning. Empty means "let the provider decide".
 	ReasoningEffort string
+	// PromptCacheKey, when non-empty, is an opaque stable identifier for the
+	// conversation (the session ID). Providers with server-side prefix-cache
+	// routing forward it — OpenAI `prompt_cache_key` — so consecutive requests
+	// land on a replica that already holds the cached prompt prefix instead of
+	// re-billing the full prefix each turn. Providers without an equivalent
+	// ignore it.
+	PromptCacheKey string
 }
 
 // Provider streams normalized completion events for one request.