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

@@ -37,6 +37,7 @@ 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

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

@@ -191,10 +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 {
@@ -202,7 +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)
@@ -232,9 +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

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/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/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,
@@ -3730,6 +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.
@@ -3845,6 +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
@@ -4040,6 +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/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/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/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/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)