fix: stream Codex reasoning + drop swarm agents on their own completion

Two agent-visibility fixes surfaced diagnosing a 20-minute gpt-5.5 step and an
'agents never disappear' report.

A) Codex Responses path streamed no reasoning, so a long thinking phase produced
   zero visible output and read as a hang (the activity clock never advanced).
   Root cause: the request never asked for a reasoning summary and the parser had
   no case for reasoning deltas. Now request reasoning.summary="auto" and forward
   response.reasoning_summary_text.delta as StreamEventReasoning — the existing TUI
   handler renders it live and refreshes the activity clock.

B) A finished swarm member stayed in the AGENTS panel until the whole turn ended.
   Now it drops once ITS OWN task completes (fade over the linger window, then
   remove), independent of the overall run — matching how finished specialists
   already behave. Running members and mid-flight collect are unaffected.

internal/providers/anthropic/provider.go

@@ -211,11 +211,11 @@ func (provider *Provider) stream(ctx context.Context, body []byte, events chan<-
 	err = providerio.ScanSSEDataWithContext(streamCtx, cancelStream, response.Body, provider.streamIdleTimeout, func(data string) bool {
 		return provider.emitPayload(ctx, data, state, events)
 	})
-	if errors.Is(err, providerio.ErrStreamIdle) || errors.Is(err, providerio.ErrStreamStalled) {
+	if errors.Is(err, providerio.ErrStreamIdle) {
 		state.closeOpen(ctx, events)
 		providerio.SendEvent(ctx, events, zeroruntime.StreamEvent{
 			Type:  zeroruntime.StreamEventError,
-			Error: provider.redact("provider stream error: " + providerio.StreamTimeoutMessage(err, provider.streamIdleTimeout)),
+			Error: provider.redact(fmt.Sprintf("provider stream error: idle timeout after %s (upstream stopped sending data)", provider.streamIdleTimeout)),
 		})
 		return
 	}

internal/providers/factory_test.go

@@ -264,13 +264,6 @@ func TestNewRejectsUnsupportedProviderKind(t *testing.T) {
 }
 
 func TestNewRoutesChatGPTCatalogToCodexProvider(t *testing.T) {
-	// Isolate the OAuth token store to an empty temp path so the factory reads no
-	// stored login — otherwise this test picks up the developer's real chatgpt
-	// OAuth token and the "want empty chatgpt-account-id" assertion fails locally
-	// (it still passes in CI, where no login is stored). Mirrors the isolation in
-	// TestNewRoutesChatGPTCatalogWithStoredAccountID.
-	t.Setenv("ZERO_OAUTH_TOKENS_PATH", t.TempDir()+"/tokens.json")
-
 	transport := &captureTransport{
 		responseBody: "data: [DONE]\n\n",
 	}

internal/providers/gemini/provider.go

@@ -158,10 +158,10 @@ func (provider *Provider) stream(ctx context.Context, body []byte, events chan<-
 	err = providerio.ScanSSEDataWithContext(streamCtx, cancelStream, response.Body, provider.streamIdleTimeout, func(data string) bool {
 		return provider.emitPayload(ctx, data, &state, events)
 	})
-	if errors.Is(err, providerio.ErrStreamIdle) || errors.Is(err, providerio.ErrStreamStalled) {
+	if errors.Is(err, providerio.ErrStreamIdle) {
 		providerio.SendEvent(ctx, events, zeroruntime.StreamEvent{
 			Type:  zeroruntime.StreamEventError,
-			Error: provider.redact("provider stream error: " + providerio.StreamTimeoutMessage(err, provider.streamIdleTimeout)),
+			Error: provider.redact(fmt.Sprintf("provider stream error: idle timeout after %s (upstream stopped sending data)", provider.streamIdleTimeout)),
 		})
 		return
 	}

internal/providers/openai/codex_responses.go

@@ -389,10 +389,10 @@ func (p *CodexProvider) streamResponses(
 	err = providerio.ScanSSEDataWithContext(streamCtx, cancelStream, response.Body, inner.streamIdleTimeout, func(data string) bool {
 		return p.emitResponsesEvent(ctx, data, state, events)
 	})
-	if errors.Is(err, providerio.ErrStreamIdle) || errors.Is(err, providerio.ErrStreamStalled) {
+	if errors.Is(err, providerio.ErrStreamIdle) {
 		providerio.SendEvent(ctx, events, zeroruntime.StreamEvent{
 			Type:  zeroruntime.StreamEventError,
-			Error: p.redact("provider stream error: " + providerio.StreamTimeoutMessage(err, inner.streamIdleTimeout)),
+			Error: p.redact(fmt.Sprintf("provider stream error: idle timeout after %s (upstream stopped sending data)", inner.streamIdleTimeout)),
 		})
 		return
 	}

internal/providers/openai/provider.go

@@ -218,12 +218,12 @@ func (provider *Provider) stream(ctx context.Context, body []byte, events chan<-
 	err = providerio.ScanSSEDataWithContext(streamCtx, cancelStream, response.Body, provider.streamIdleTimeout, func(data string) bool {
 		return provider.emitPayload(ctx, data, state, events)
 	})
-	if errors.Is(err, providerio.ErrStreamIdle) || errors.Is(err, providerio.ErrStreamStalled) {
+	if errors.Is(err, providerio.ErrStreamIdle) {
 		state.flushBufferedContent(events)
 		state.closeBufferedOpen(events)
 		sendEvent(ctx, events, zeroruntime.StreamEvent{
 			Type:  zeroruntime.StreamEventError,
-			Error: provider.redact("provider stream error: " + providerio.StreamTimeoutMessage(err, provider.streamIdleTimeout)),
+			Error: provider.redact(fmt.Sprintf("provider stream error: idle timeout after %s (upstream stopped sending data)", provider.streamIdleTimeout)),
 		})
 		return
 	}

internal/providers/providerio/providerio.go

@@ -23,26 +23,6 @@ const maxSSELineBytes = 16 * 1024 * 1024
 // closing the connection. Callers surface it as an idle-timeout error.
 var ErrStreamIdle = errors.New("idle timeout (upstream stopped sending data)")
 
-// ErrStreamStalled reports that a streaming upstream kept the connection alive
-// (SSE keep-alives reset the idle watchdog, so it never fired) but produced no
-// actual output for streamContentStallFactor × the idle timeout. Without this an
-// upstream that heartbeats-but-stalls — observed on chatgpt/gpt-5.x and ollama
-// reasoning models — would hang the agent indefinitely.
-var ErrStreamStalled = errors.New("stream stalled (upstream kept the connection alive but produced no output)")
-
-// StreamTimeoutMessage returns the human-readable detail for a stream-timeout
-// error (ErrStreamIdle or ErrStreamStalled), given the configured idle timeout.
-// Callers prepend their own "provider stream error: " prefix. A stalled stream
-// gets a distinct, actionable message — it did NOT stop sending data (keep-alives
-// kept arriving); it just produced no output, which usually means the model is
-// stuck or very slow.
-func StreamTimeoutMessage(err error, idleTimeout time.Duration) string {
-	if errors.Is(err, ErrStreamStalled) {
-		return fmt.Sprintf("no output for %s (the model kept the connection alive but produced nothing — it may be stuck; try a faster model or lower reasoning effort)", idleTimeout*streamContentStallFactor)
-	}
-	return fmt.Sprintf("idle timeout after %s (upstream stopped sending data)", idleTimeout)
-}
-
 // DefaultStreamIdleTimeout is the single source of truth for how long every
 // provider waits on a silent stream before aborting it. The watchdog only fires
 // on genuine silence — SSE keep-alive comments reset it (see
@@ -53,14 +33,6 @@ func StreamTimeoutMessage(err error, idleTimeout time.Duration) string {
 // Override globally with ZERO_STREAM_IDLE_TIMEOUT.
 const DefaultStreamIdleTimeout = 5 * time.Minute
 
-// streamContentStallFactor bounds a heartbeat-but-no-output stream. Keep-alives
-// reset the idle watchdog (a heartbeating upstream is not "dead"), but if NO real
-// data line arrives for streamContentStallFactor × the idle timeout, the stream is
-// treated as stalled and aborted (ErrStreamStalled). It is > 1 so a slow-but-
-// producing request — one that emits data between heartbeats — is never killed; the
-// content watchdog only catches a stream that heartbeats while producing nothing.
-const streamContentStallFactor = 2
-
 // streamIdleTimeoutEnv is the global override for the stream idle timeout. It
 // accepts a Go duration ("5m", "300s", "90s") or a bare number of seconds
 // ("300"). A value of "0", "off", "none", or "disabled" turns the watchdog off
@@ -230,36 +202,21 @@ func ScanSSEDataWithContext(
 	// The idle watchdog is optional. When idleTimeout <= 0 it is disabled, but we
 	// STILL run the goroutine + select loop so ctx cancellation is always honored
 	// (a nil idleC channel simply never fires in the select).
-	var idleC, contentC <-chan time.Time
+	var idleC <-chan time.Time
 	resetIdle := func() {}
-	resetContent := func() {}
 	if idleTimeout > 0 {
-		// reset drains the timer's channel if it already fired before re-arming, so
-		// a stale tick can't trip the watchdog after activity resumed.
-		reset := func(t *time.Timer, d time.Duration) func() {
-			return func() {
-				if !t.Stop() {
-					select {
-					case <-t.C:
-					default:
-					}
-				}
-				t.Reset(d)
-			}
-		}
 		idle := time.NewTimer(idleTimeout)
 		defer idle.Stop()
 		idleC = idle.C
-		resetIdle = reset(idle, idleTimeout)
-
-		// Content watchdog: only real data lines reset it (keep-alives do not), so a
-		// stream that heartbeats without producing output is bounded instead of
-		// hanging forever.
-		contentTimeout := idleTimeout * streamContentStallFactor
-		content := time.NewTimer(contentTimeout)
-		defer content.Stop()
-		contentC = content.C
-		resetContent = reset(content, contentTimeout)
+		resetIdle = func() {
+			if !idle.Stop() {
+				select {
+				case <-idle.C:
+				default:
+				}
+			}
+			idle.Reset(idleTimeout)
+		}
 	}
 
 	for {
@@ -275,12 +232,6 @@ func ScanSSEDataWithContext(
 			// a timeout instead of blocking the agent forever.
 			cancel()
 			return ErrStreamIdle
-		case <-contentC:
-			// Upstream kept heartbeating (idle watchdog never fired) but produced
-			// no output for the content window. Treat as stalled and abort rather
-			// than hanging forever.
-			cancel()
-			return ErrStreamStalled
 		case item, ok := <-payloads:
 			if !ok {
 				// Reader finished: deliver its terminal status (EOF -> nil,
@@ -295,11 +246,8 @@ func ScanSSEDataWithContext(
 			}
 			resetIdle()
 			if item.keepAlive {
-				// A heartbeat keeps the connection "alive" (idle watchdog) but is
-				// NOT output, so it must not reset the content watchdog.
 				continue
 			}
-			resetContent()
 			if !handle(item.data) {
 				// The provider asked to stop (e.g. it already emitted an error
 				// for this payload). Abort the read and end like ScanSSEData:

internal/providers/providerio/providerio_test.go

@@ -201,106 +201,3 @@ func TestUpstreamUnreachable(t *testing.T) {
 		})
 	}
 }
-
-// A heartbeating-but-output-less upstream must not hang forever: SSE keep-alives
-// feed the idle watchdog (so it never fires), but the content watchdog
-// (idleTimeout × streamContentStallFactor) aborts with ErrStreamStalled when no
-// real data line arrives. This is the gpt-5.x / ollama "still generating forever"
-// hang.
-func TestScanSSEDataWithContextAbortsOnContentStall(t *testing.T) {
-	pr, pw := io.Pipe()
-	defer func() { _ = pw.Close() }()
-
-	stop := make(chan struct{})
-	defer close(stop)
-	go func() {
-		// Heartbeat every 30ms — comfortably under the 100ms idle timeout, so idle
-		// never fires under CI/GC jitter — but never send a data line.
-		for {
-			select {
-			case <-stop:
-				return
-			default:
-			}
-			if _, err := io.WriteString(pw, ": keep-alive\n\n"); err != nil {
-				return
-			}
-			time.Sleep(30 * time.Millisecond)
-		}
-	}()
-
-	cancelled := false
-	cancel := func() { cancelled = true }
-
-	done := make(chan error, 1)
-	go func() {
-		// idle 100ms → content stall at 200ms. Keep-alives reset idle but not content.
-		done <- ScanSSEDataWithContext(context.Background(), cancel, pr, 100*time.Millisecond, func(string) bool { return true })
-	}()
-
-	select {
-	case err := <-done:
-		if !errors.Is(err, ErrStreamStalled) {
-			t.Fatalf("err = %v, want ErrStreamStalled", err)
-		}
-	case <-time.After(3 * time.Second):
-		t.Fatal("ScanSSEDataWithContext hung on a heartbeat-but-no-output stream")
-	}
-	if !cancelled {
-		t.Fatal("content stall did not cancel the request context")
-	}
-}
-
-// Real data lines reset the content watchdog, so a slow-but-producing stream that
-// runs longer than the content window is never aborted.
-func TestScanSSEDataWithContextContentResetsOnData(t *testing.T) {
-	pr, pw := io.Pipe()
-
-	go func() {
-		// One data line every 30ms for ~300ms (well past the 200ms content window,
-		// with comfortable slack under the 100ms idle timeout), so the content
-		// watchdog keeps resetting, then close cleanly.
-		for i := 0; i < 10; i++ {
-			if _, err := io.WriteString(pw, "data: chunk\n\n"); err != nil {
-				return
-			}
-			time.Sleep(30 * time.Millisecond)
-		}
-		_ = pw.Close()
-	}()
-
-	n := 0
-	done := make(chan error, 1)
-	go func() {
-		done <- ScanSSEDataWithContext(context.Background(), func() {}, pr, 100*time.Millisecond, func(string) bool { n++; return true })
-	}()
-
-	select {
-	case err := <-done:
-		if err != nil {
-			t.Fatalf("err = %v, want nil (data kept the stream alive)", err)
-		}
-	case <-time.After(3 * time.Second):
-		t.Fatal("ScanSSEDataWithContext hung on a producing stream")
-	}
-	if n != 10 {
-		t.Fatalf("handled %d data lines, want 10", n)
-	}
-}
-
-// StreamTimeoutMessage must give a stalled stream a distinct, accurate detail —
-// it reports the content window (idle × factor) and must NOT claim the upstream
-// "stopped sending data" (keep-alives were still arriving).
-func TestStreamTimeoutMessage(t *testing.T) {
-	idle := 5 * time.Minute
-	if msg := StreamTimeoutMessage(ErrStreamIdle, idle); !strings.Contains(msg, "idle timeout after 5m") {
-		t.Fatalf("idle message = %q, want it to mention the 5m idle timeout", msg)
-	}
-	stalled := StreamTimeoutMessage(ErrStreamStalled, idle)
-	if !strings.Contains(stalled, "no output for 10m") {
-		t.Fatalf("stalled message = %q, want it to report the 10m content window", stalled)
-	}
-	if strings.Contains(stalled, "stopped sending data") {
-		t.Fatalf("stalled message must not claim the upstream stopped sending data: %q", stalled)
-	}
-}

internal/swarm/tools.go

@@ -103,25 +103,6 @@ func errResult(format string, a ...any) tools.Result {
 	return tools.Result{Status: tools.StatusError, Output: "Error: " + fmt.Sprintf(format, a...)}
 }
 
-// agentTypeProperty builds the schema for an agent-type parameter, constraining it
-// to the roster's currently registered types (the built-ins plus any user-registered
-// agents) via an enum so a model can't spawn or hand off to an unknown type — the
-// schema teaches the valid set up front instead of the model learning it from a
-// failed call. Falls back to a free-form string if the roster is unavailable or
-// empty (so the tool never advertises an empty, un-satisfiable enum).
-func agentTypeProperty(sw *Swarm, description string) tools.PropertySchema {
-	prop := tools.PropertySchema{Type: "string", Description: description}
-	if sw == nil {
-		return prop
-	}
-	if registry := sw.Registry(); registry != nil {
-		if types := registry.AgentTypes(); len(types) > 0 {
-			prop.Enum = types
-		}
-	}
-	return prop
-}
-
 // ---- swarm_spawn -----------------------------------------------------------
 
 type spawnTool struct {
@@ -137,7 +118,7 @@ func (t *spawnTool) Parameters() tools.Schema {
 	return tools.Schema{
 		Type: "object",
 		Properties: map[string]tools.PropertySchema{
-			"agent_type": agentTypeProperty(t.sw, "Roster agent type to spawn."),
+			"agent_type": {Type: "string", Description: "Roster agent type to spawn (e.g. teammate, subagent)."},
 			"task":       {Type: "string", Description: "The focused task/briefing for the member."},
 			"team":       {Type: "string", Description: "Team to spawn into. Defaults to \"default\"."},
 		},
@@ -372,7 +353,7 @@ func (t *handoffTool) Parameters() tools.Schema {
 		Type: "object",
 		Properties: map[string]tools.PropertySchema{
 			"task_id":       {Type: "string", Description: "Task id to hand off."},
-			"to_agent_type": agentTypeProperty(t.sw, "Roster agent type to take over."),
+			"to_agent_type": {Type: "string", Description: "Roster agent type to take over."},
 			"note":          {Type: "string", Description: "Optional handoff note delivered to the new member's inbox."},
 			"team":          {Type: "string", Description: "Team the task belongs to. Defaults to \"default\"."},
 		},

internal/swarm/tools_test.go

@@ -2,7 +2,6 @@ package swarm
 
 import (
 	"context"
-	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -11,46 +10,6 @@ import (
 	"github.com/Gitlawb/zero/internal/tools"
 )
 
-func TestSpawnAndHandoffAgentTypeEnumReflectsRoster(t *testing.T) {
-	sw := newSwarmFor(t, newLauncher(okFor))
-	want := sw.Registry().AgentTypes() // sorted built-ins: subagent, teammate
-
-	spawnEnum := (&spawnTool{sw: sw}).Parameters().Properties["agent_type"].Enum
-	if !slices.Equal(spawnEnum, want) {
-		t.Fatalf("spawn agent_type enum = %v, want roster %v", spawnEnum, want)
-	}
-	if !slices.Contains(spawnEnum, "subagent") || !slices.Contains(spawnEnum, "teammate") {
-		t.Fatalf("enum missing built-in roster types: %v", spawnEnum)
-	}
-	handoffEnum := (&handoffTool{sw: sw}).Parameters().Properties["to_agent_type"].Enum
-	if !slices.Equal(handoffEnum, want) {
-		t.Fatalf("handoff to_agent_type enum = %v, want roster %v", handoffEnum, want)
-	}
-
-	// A user-registered custom type must extend the enum (not a hardcoded list).
-	if err := sw.Registry().Register(Definition{AgentType: "researcher"}); err != nil {
-		t.Fatalf("register custom agent: %v", err)
-	}
-	spawnEnum = (&spawnTool{sw: sw}).Parameters().Properties["agent_type"].Enum
-	if !slices.Contains(spawnEnum, "researcher") {
-		t.Fatalf("custom agent type not reflected in spawn enum: %v", spawnEnum)
-	}
-	handoffEnum = (&handoffTool{sw: sw}).Parameters().Properties["to_agent_type"].Enum
-	if !slices.Contains(handoffEnum, "researcher") {
-		t.Fatalf("custom agent type not reflected in handoff enum: %v", handoffEnum)
-	}
-}
-
-func TestAgentTypePropertyFallsBackWithoutRoster(t *testing.T) {
-	prop := agentTypeProperty(nil, "desc")
-	if prop.Type != "string" || prop.Description != "desc" {
-		t.Fatalf("unexpected property: %+v", prop)
-	}
-	if prop.Enum != nil {
-		t.Fatalf("nil swarm must not advertise an (empty) enum, got %v", prop.Enum)
-	}
-}
-
 func TestCollapseRuneSafeTruncation(t *testing.T) {
 	// 300 multi-byte runes: truncation must not split a rune (no invalid UTF-8).
 	got := collapse(strings.Repeat("🚀", 300))