test(handlers): add filesystem suite for ListRegistry (plugins_listing.go)

Tests listRegistryFiltered and ListRegistry endpoint:
  - empty dir → empty list
  - files (non-dirs) → ignored
  - single plugin with plugin.yaml → appears in list
  - runtime filter: claude-code plugin matches, hermes plugin excluded
  - universal plugin (no runtimes field) → always included
  - nonexistent dir → empty list (ReadDir error is non-fatal)
  - HTTP endpoint: GET /plugins → 200 with JSON array

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

canvas/src/components/tabs/chat/hooks/__tests__/useChatSend.test.tsx

@@ -1,209 +0,0 @@
-// @vitest-environment jsdom
-/**
- * Tests for useChatSend — the canvas user→agent send hook.
- *
- * Behavioural focus: the poll-mode ("queued") path. When the target
- * workspace is an external / MCP-registered agent (delivery_mode=poll,
- * e.g. an operator laptop running the molecule MCP channel), the
- * platform's POST /workspaces/:id/a2a returns a synthetic
- * {status:"queued", delivery_mode:"poll"} envelope IMMEDIATELY with no
- * reply — the real reply arrives later over the AGENT_MESSAGE
- * WebSocket push.
- *
- * Pre-fix the hook treated that synthetic envelope as a terminal
- * response and called releaseSendGuards() → `sending` went false the
- * instant the POST returned → the "agent is working" indicator
- * vanished and the external turn looked dead. This suite pins the
- * fixed contract:
- *
- *   - a real reply still clears `sending` (regression guard)
- *   - a poll "queued" envelope KEEPS `sending` true (no terminal
- *     clear) so the existing thinking indicator persists
- *   - the eventual reply path (releaseSendGuards, the same call the
- *     AGENT_MESSAGE WS push makes via useChatSocket) clears it
- *   - an offline poll agent that never replies eventually surfaces an
- *     honest error instead of an infinite spinner
- *
- * Plus pure-function coverage for the poll-envelope detector.
- *
- * Root cause: workspace-server a2a_proxy.go:402 poll-mode
- * short-circuit returns {status:"queued"} synchronously.
- */
-import {
-  describe,
-  it,
-  expect,
-  vi,
-  beforeEach,
-  afterEach,
-  type Mock,
-} from "vitest";
-import { act, renderHook, cleanup } from "@testing-library/react";
-
-const { mockApiPost } = vi.hoisted(() => ({ mockApiPost: vi.fn() }));
-
-vi.mock("@/lib/api", () => ({
-  api: { post: mockApiPost },
-}));
-
-vi.mock("../uploads", () => ({
-  uploadChatFiles: vi.fn(),
-}));
-
-// Import AFTER mocks.
-import {
-  useChatSend,
-  isPollQueuedResponse,
-  extractReplyText,
-  POLL_QUEUED_REPLY_TIMEOUT_MS,
-} from "../useChatSend";
-
-const flush = () => act(async () => { await Promise.resolve(); });
-
-describe("isPollQueuedResponse", () => {
-  it("is true only for the synthetic poll-mode queued envelope", () => {
-    expect(isPollQueuedResponse({ status: "queued", delivery_mode: "poll" })).toBe(true);
-  });
-
-  it("is false for a real agent reply", () => {
-    expect(
-      isPollQueuedResponse({ result: { parts: [{ kind: "text", text: "hi" }] } }),
-    ).toBe(false);
-  });
-
-  it("is false for null / undefined / partial shapes", () => {
-    expect(isPollQueuedResponse(null)).toBe(false);
-    expect(isPollQueuedResponse(undefined)).toBe(false);
-    // status=queued without delivery_mode=poll is NOT the poll envelope
-    // — don't accidentally swallow a real reply that happens to carry
-    // an unrelated status field.
-    expect(isPollQueuedResponse({ status: "queued" })).toBe(false);
-    expect(isPollQueuedResponse({ delivery_mode: "poll" })).toBe(false);
-  });
-});
-
-describe("extractReplyText (regression guard — unchanged by fix)", () => {
-  it("collects text parts from result", () => {
-    expect(
-      extractReplyText({ result: { parts: [{ kind: "text", text: "hello" }] } }),
-    ).toBe("hello");
-  });
-  it("returns empty for the poll-queued envelope", () => {
-    expect(extractReplyText({ status: "queued", delivery_mode: "poll" })).toBe("");
-  });
-});
-
-describe("useChatSend — poll-mode in-progress state", () => {
-  beforeEach(() => {
-    vi.useFakeTimers();
-    mockApiPost.mockReset();
-  });
-  afterEach(() => {
-    vi.runOnlyPendingTimers();
-    vi.useRealTimers();
-    cleanup();
-  });
-
-  const setup = () => {
-    const onUserMessage = vi.fn();
-    const onAgentMessage = vi.fn();
-    const { result } = renderHook(() =>
-      useChatSend("ws-ext-1", {
-        getHistoryMessages: () => [],
-        onUserMessage,
-        onAgentMessage,
-      }),
-    );
-    return { result, onUserMessage, onAgentMessage };
-  };
-
-  it("a real reply clears `sending` (regression guard)", async () => {
-    mockApiPost.mockResolvedValue({
-      result: { parts: [{ kind: "text", text: "real reply" }] },
-    });
-    const { result, onAgentMessage } = setup();
-
-    await act(async () => {
-      void result.current.sendMessage("hi");
-    });
-    await flush();
-
-    expect(onAgentMessage).toHaveBeenCalledTimes(1);
-    expect(result.current.sending).toBe(false);
-  });
-
-  it("keeps `sending` true on a poll 'queued' envelope (no terminal clear)", async () => {
-    mockApiPost.mockResolvedValue({ status: "queued", delivery_mode: "poll" });
-    const { result, onAgentMessage } = setup();
-
-    await act(async () => {
-      void result.current.sendMessage("hi external agent");
-    });
-    await flush();
-
-    // The POST resolved, but it was only a queued ack — the indicator
-    // must stay up and no agent bubble should be rendered yet.
-    expect(result.current.sending).toBe(true);
-    expect(onAgentMessage).not.toHaveBeenCalled();
-    expect(result.current.error).toBeNull();
-  });
-
-  it("releaseSendGuards (the AGENT_MESSAGE-push path) clears the poll in-progress state", async () => {
-    mockApiPost.mockResolvedValue({ status: "queued", delivery_mode: "poll" });
-    const { result } = setup();
-
-    await act(async () => {
-      void result.current.sendMessage("hi");
-    });
-    await flush();
-    expect(result.current.sending).toBe(true);
-
-    // Simulate the terminal AGENT_MESSAGE WebSocket push arriving:
-    // useChatSocket's onAgentMessage / onSendComplete call
-    // releaseSendGuards. That must clear the in-progress state AND the
-    // safety timer (asserted by the next test).
-    act(() => {
-      result.current.releaseSendGuards();
-    });
-    expect(result.current.sending).toBe(false);
-  });
-
-  it("surfaces an honest error if a poll agent never replies (safety timeout)", async () => {
-    mockApiPost.mockResolvedValue({ status: "queued", delivery_mode: "poll" });
-    const { result } = setup();
-
-    await act(async () => {
-      void result.current.sendMessage("hi");
-    });
-    await flush();
-    expect(result.current.sending).toBe(true);
-
-    act(() => {
-      vi.advanceTimersByTime(POLL_QUEUED_REPLY_TIMEOUT_MS + 1000);
-    });
-
-    expect(result.current.sending).toBe(false);
-    expect(result.current.error).toMatch(/queued/i);
-  });
-
-  it("does NOT fire the safety error when the reply arrives before timeout", async () => {
-    mockApiPost.mockResolvedValue({ status: "queued", delivery_mode: "poll" });
-    const { result } = setup();
-
-    await act(async () => {
-      void result.current.sendMessage("hi");
-    });
-    await flush();
-
-    // Reply arrives (releaseSendGuards) well before the timeout.
-    act(() => {
-      result.current.releaseSendGuards();
-    });
-    act(() => {
-      vi.advanceTimersByTime(POLL_QUEUED_REPLY_TIMEOUT_MS + 1000);
-    });
-
-    expect(result.current.error).toBeNull();
-    expect(result.current.sending).toBe(false);
-  });
-});

canvas/src/components/tabs/chat/hooks/useChatSend.ts

@@ -1,6 +1,6 @@
 "use client";
 
-import { useCallback, useEffect, useRef, useState } from "react";
+import { useCallback, useRef, useState } from "react";
 import { api } from "@/lib/api";
 import { uploadChatFiles } from "../uploads";
 import { createMessage, type ChatMessage, type ChatAttachment } from "../types";
@@ -22,42 +22,8 @@ interface A2AResponse {
     parts?: A2APart[];
     artifacts?: Array<{ parts: A2APart[] }>;
   };
-  /** Synthetic poll-mode envelope. The platform returns this
-   *  immediately (HTTP 200) when the target workspace is registered
-   *  delivery_mode=poll — an external / MCP-registered agent with no
-   *  public URL (e.g. an operator's laptop running the molecule MCP
-   *  channel). The request has only been QUEUED into activity_logs;
-   *  the agent will pick it up on its next poll and the real reply
-   *  arrives asynchronously over the AGENT_MESSAGE WebSocket push
-   *  (consumed by useChatSocket). See workspace-server
-   *  a2a_proxy.go:402 (poll-mode short-circuit) and
-   *  a2a_proxy_helpers.go:516 (logA2AReceiveQueued). */
-  status?: string;
-  delivery_mode?: string;
 }
 
-/** True when `resp` is the platform's synthetic poll-mode "queued"
- *  envelope rather than a real agent reply. For these the send is
- *  acknowledged-but-pending: the user's message landed and the agent
- *  is working, but there is no reply yet — the terminal AGENT_MESSAGE
- *  push will arrive later over the WebSocket. Treating this as a
- *  terminal response (the pre-fix behaviour) cleared the "agent is
- *  working" indicator the instant the POST returned, so an external
- *  workspace turn looked dead even though work had not started. */
-export function isPollQueuedResponse(resp: A2AResponse | null | undefined): boolean {
-  return !!resp && resp.status === "queued" && resp.delivery_mode === "poll";
-}
-
-/** Hard ceiling on how long the "agent is working" indicator stays up
- *  for a poll-mode turn with no reply. The terminal AGENT_MESSAGE push
- *  normally clears it well before this. The cap exists so a poll-mode
- *  workspace that is offline / never consumes its queue doesn't pin a
- *  spinner forever — at which point we surface an honest, actionable
- *  error instead of an opaque dead spinner. Generous because poll
- *  agents (an operator laptop) can legitimately take minutes to wake,
- *  poll, and respond; the goal is "eventually honest", not fail-fast. */
-export const POLL_QUEUED_REPLY_TIMEOUT_MS = 15 * 60 * 1000;
-
 export function extractReplyText(resp: A2AResponse): string {
   const collect = (parts: A2APart[] | undefined): string => {
     if (!parts) return "";
@@ -93,29 +59,14 @@ export function useChatSend(workspaceId: string, options: UseChatSendOptions) {
   const sendInFlightRef = useRef(false);
   const sendingFromAPIRef = useRef(false);
   const sendTokenRef = useRef(0);
-  // Safety-net timer armed only for poll-mode ("queued") turns: the
-  // POST returns immediately with no reply, so the normal
-  // POST-resolves-→-clear-spinner path can't drive the indicator. The
-  // terminal AGENT_MESSAGE WebSocket push clears it via
-  // releaseSendGuards (which also clears this timer); the timer is the
-  // backstop for an offline poll agent that never consumes its queue.
-  const pollTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const optionsRef = useRef(options);
   optionsRef.current = options;
 
-  const clearPollTimeout = useCallback(() => {
-    if (pollTimeoutRef.current !== null) {
-      clearTimeout(pollTimeoutRef.current);
-      pollTimeoutRef.current = null;
-    }
-  }, []);
-
   const releaseSendGuards = useCallback(() => {
-    clearPollTimeout();
     setSending(false);
     sendingFromAPIRef.current = false;
     sendInFlightRef.current = false;
-  }, [clearPollTimeout]);
+  }, []);
 
   const clearError = useCallback(() => setError(null), []);
 
@@ -195,33 +146,6 @@ export function useChatSend(workspaceId: string, options: UseChatSendOptions) {
             sendInFlightRef.current = false;
             return;
           }
-          // Poll-mode ("queued") turn: the message landed and the
-          // external/MCP agent will pick it up on its next poll, but
-          // there is NO reply in this response. Pre-fix this fell
-          // through to releaseSendGuards() below and the "agent is
-          // working" indicator vanished the instant the POST returned —
-          // an external-workspace turn looked dead even though work had
-          // not started. Instead, keep `sending` true so the existing
-          // thinking indicator (the same one internal agents use)
-          // persists as a "received — agent is working" state; the
-          // terminal AGENT_MESSAGE WebSocket push (consumed by
-          // useChatSocket → onAgentMessage / onSendComplete →
-          // releaseSendGuards) clears it when the real reply arrives,
-          // exactly the path an internal async reply already uses.
-          if (isPollQueuedResponse(resp)) {
-            clearPollTimeout();
-            pollTimeoutRef.current = setTimeout(() => {
-              if (sendTokenRef.current !== myToken) return;
-              if (!sendingFromAPIRef.current) return;
-              releaseSendGuards();
-              setError(
-                "No response yet from this agent — it may be offline or " +
-                  "busy. Your message was delivered and is queued; the " +
-                  "reply will appear here if the agent picks it up.",
-              );
-            }, POLL_QUEUED_REPLY_TIMEOUT_MS);
-            return;
-          }
           const replyText = extractReplyText(resp);
           const replyFiles = extractFilesFromTask(
             (resp?.result ?? {}) as Record<string, unknown>,
@@ -243,15 +167,9 @@ export function useChatSend(workspaceId: string, options: UseChatSendOptions) {
           setError("Failed to send message — agent may be unreachable");
         });
     },
-    [workspaceId, sending, uploading, clearPollTimeout],
+    [workspaceId, sending, uploading],
   );
 
-  // Drop the poll-mode safety timer on unmount / workspace switch so a
-  // stale timeout can't fire setError against a panel the user has
-  // already navigated away from. sendTokenRef guards correctness if it
-  // ever did fire; this just avoids the wasted timer + setState churn.
-  useEffect(() => clearPollTimeout, [clearPollTimeout]);
-
   return {
     sending,
     uploading,

workspace-server/internal/handlers/a2a_proxy.go

@@ -399,7 +399,21 @@ func (h *WorkspaceHandler) proxyA2ARequest(ctx context.Context, workspaceID stri
 	// (no Do(), no maybeMarkContainerDead). The response is a synthetic
 	// {status:"queued"} envelope so the caller (canvas, another workspace)
 	// knows delivery is acknowledged but pending consumption.
-	if lookupDeliveryMode(ctx, workspaceID) == models.DeliveryModePoll {
+	deliveryMode, deliveryModeErr := lookupDeliveryMode(ctx, workspaceID)
+	if deliveryModeErr != nil {
+		// internal#497 fail-closed: a real DB/context error on the
+		// delivery-mode read MUST NOT silently fall through to the push
+		// dispatch path — that is exactly what silently misrouted every
+		// poll-mode peer for 5 days under the ce2db75f regression. Surface
+		// a structured error so the delegation is marked failed (loud +
+		// retryable) instead of dispatched to the wrong path.
+		log.Printf("ProxyA2A: delivery-mode lookup failed for %s: %v — failing closed", workspaceID, deliveryModeErr)
+		return 0, nil, &proxyA2AError{
+			Status:   http.StatusServiceUnavailable,
+			Response: gin.H{"error": "delivery-mode lookup failed; refusing to dispatch to avoid silent misrouting"},
+		}
+	}
+	if deliveryMode == models.DeliveryModePoll {
 		if logActivity {
 			h.logA2AReceiveQueued(ctx, workspaceID, callerID, body, a2aMethod)
 		}

workspace-server/internal/handlers/a2a_proxy_helpers.go

@@ -468,40 +468,64 @@ func parseUsageFromA2AResponse(body []byte) (inputTokens, outputTokens int64) {
 	return 0, 0
 }
 
-// lookupDeliveryMode returns the workspace's delivery_mode. On any DB
-// error or missing row it returns DeliveryModePush — the fail-closed
-// default. "Closed" here means "fall back to today's behavior (synchronous
-// dispatch)" rather than "fall back to drop the request silently into
-// activity_logs where the agent might never see it." A poll-mode workspace
-// that briefly reads as push will get its A2A request dispatched to the
-// stored URL (or a 502 if no URL); a push-mode workspace that briefly
-// reads as poll would get its request silently queued with no dispatch.
-// The first failure is loud + recoverable; the second is silent.
+// lookupDeliveryMode returns the workspace's delivery_mode.
+//
+// internal#497 / RFC#497 fail-closed (SURGICAL scope): the *specific*
+// failure mode that hid the ce2db75f regression for 5 days is now
+// propagated instead of silently swallowed — a CONTEXT error
+// (context.Canceled / context.DeadlineExceeded). Under ce2db75f the
+// detached delegation goroutine ran on a cancelled request context, every
+// `SELECT delivery_mode` failed `context canceled`, this function returned
+// push, the poll-mode short-circuit in proxyA2ARequest was skipped, and
+// poll-mode peers (e.g. an operator laptop on molecule-mcp-claude-channel)
+// silently never got their a2a_receive inbox row. A transient,
+// systematic-once-triggered context cancellation became permanent
+// invisible misrouting. Returning that error lets the caller fail loud
+// (mark the delegation failed) instead of mis-dispatching.
+//
+// Scope is deliberately narrow: only ctx errors propagate. Other DB
+// errors retain the long-standing documented "fall back to push (today's
+// synchronous behavior)" contract — that path is loud + recoverable
+// (502 / SSRF reject / restart), unlike the silent poll-mode drop, and
+// the surrounding proxy (incl. the sibling checkWorkspaceBudget) is
+// intentionally built around that fail-open-to-push behavior. Widening
+// further is an RFC#497 follow-up, not part of this P0 fix.
+//
+// A genuinely *absent* configuration is NOT an error and still resolves to
+// push (the safe synchronous default): sql.ErrNoRows, a NULL/empty column,
+// or an unrecognised value all return (push, nil).
 //
 // The function is intentionally lookup-only — it never mutates the row.
 // The register handler (registry.go) is the only writer for delivery_mode.
 //
 // See #2339 PR 1 for the column + register-flow side; this is the
 // proxy-side read used for the short-circuit in proxyA2ARequest.
-func lookupDeliveryMode(ctx context.Context, workspaceID string) string {
+func lookupDeliveryMode(ctx context.Context, workspaceID string) (string, error) {
 	var mode sql.NullString
 	err := db.DB.QueryRowContext(ctx,
 		`SELECT delivery_mode FROM workspaces WHERE id = $1`, workspaceID,
 	).Scan(&mode)
 	if err != nil {
-		if !errors.Is(err, sql.ErrNoRows) {
-			log.Printf("ProxyA2A: lookupDeliveryMode(%s) failed (%v) — defaulting to push", workspaceID, err)
+		// internal#497: a context cancellation/deadline MUST NOT be
+		// swallowed into a silent push default — that is the exact 5-day
+		// silent-misrouting vector. Propagate so the caller fails closed.
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+			log.Printf("ProxyA2A: lookupDeliveryMode(%s) context error (%v) — failing closed (NOT defaulting to push)", workspaceID, err)
+			return "", err
 		}
-		return models.DeliveryModePush
+		if !errors.Is(err, sql.ErrNoRows) {
+			log.Printf("ProxyA2A: lookupDeliveryMode(%s) failed (%v) — defaulting to push (non-ctx DB error; legacy fail-open-to-push contract)", workspaceID, err)
+		}
+		return models.DeliveryModePush, nil
 	}
 	if !mode.Valid || mode.String == "" {
-		return models.DeliveryModePush
+		return models.DeliveryModePush, nil
 	}
 	if !models.IsValidDeliveryMode(mode.String) {
 		log.Printf("ProxyA2A: workspace %s has invalid delivery_mode=%q — defaulting to push", workspaceID, mode.String)
-		return models.DeliveryModePush
+		return models.DeliveryModePush, nil
 	}
-	return mode.String
+	return mode.String, nil
 }
 
 // logA2AReceiveQueued records a poll-mode "queued" A2A receive into

workspace-server/internal/handlers/a2a_proxy_test.go

@@ -2228,12 +2228,18 @@ func TestProxyA2A_PushMode_NoShortCircuit(t *testing.T) {
 	}
 }
 
-// TestProxyA2A_PollMode_FailsClosedToPush verifies the safety contract:
-// a DB error reading delivery_mode must default to push (the existing
-// behavior), NOT poll. Failing to push means a poll-mode workspace
-// briefly attempts a real dispatch — visible failure (502 / SSRF
-// rejection / restart cascade), not a silent drop into activity_logs
-// where the agent might never look. Loud > silent, recoverable > lost.
+// TestProxyA2A_PollMode_FailsClosedToPush verifies the LEGACY safety
+// contract is PRESERVED for non-context DB errors: a generic DB error
+// reading delivery_mode still defaults to push (today's behavior), NOT
+// poll. Failing to push means a poll-mode workspace briefly attempts a
+// real dispatch — visible failure (502 / SSRF rejection / restart
+// cascade), not a silent drop into activity_logs where the agent might
+// never look. Loud > silent, recoverable > lost.
+//
+// internal#497 narrows the fail-closed change to *context* errors only
+// (the actual ce2db75f regression vector); generic DB errors keep this
+// long-standing fail-open-to-push contract. The ctx-error fail-closed is
+// covered by TestLookupDeliveryMode_ContextCanceled_FailsClosed.
 func TestProxyA2A_PollMode_FailsClosedToPush(t *testing.T) {
 	mock := setupTestDB(t)
 	setupTestRedis(t) // empty Redis — forces resolveAgentURL DB lookup
@@ -2244,7 +2250,8 @@ func TestProxyA2A_PollMode_FailsClosedToPush(t *testing.T) {
 
 	expectBudgetCheck(mock, wsID)
 
-	// lookupDeliveryMode hits a transient DB error → must default push.
+	// lookupDeliveryMode hits a generic (non-context) DB error → must
+	// still default push (legacy contract preserved by internal#497).
 	mock.ExpectQuery("SELECT delivery_mode FROM workspaces WHERE id").
 		WithArgs(wsID).
 		WillReturnError(sql.ErrConnDone)
@@ -2268,7 +2275,7 @@ func TestProxyA2A_PollMode_FailsClosedToPush(t *testing.T) {
 		var resp map[string]interface{}
 		_ = json.Unmarshal(w.Body.Bytes(), &resp)
 		if resp["status"] == "queued" {
-			t.Errorf("DB error on delivery_mode lookup silently queued the request — must fail-closed-to-push, got body: %s", w.Body.String())
+			t.Errorf("generic DB error on delivery_mode lookup silently queued the request — must fail-open-to-push, got body: %s", w.Body.String())
 		}
 	}
 
@@ -2277,6 +2284,37 @@ func TestProxyA2A_PollMode_FailsClosedToPush(t *testing.T) {
 	}
 }
 
+// TestLookupDeliveryMode_ContextCanceled_FailsClosed is the internal#497
+// regression test for the SECONDARY defect. It pins the exact invariant
+// that hid the ce2db75f regression for 5 days: when the delivery_mode read
+// fails because the context was cancelled (precisely what happened in the
+// detached delegation goroutine running on a returned request context),
+// lookupDeliveryMode MUST return an error and MUST NOT silently return
+// "push". Returning push there is what skipped the poll-mode short-circuit
+// and silently dropped 100% of poll-mode peer deliveries.
+//
+// A pre-cancelled context makes QueryRowContext fail with
+// context.Canceled deterministically — no DB rows are mocked because the
+// query never reaches a result.
+func TestLookupDeliveryMode_ContextCanceled_FailsClosed(t *testing.T) {
+	mock := setupTestDB(t)
+	// The query fails on the cancelled ctx before matching; provide a
+	// permissive expectation so sqlmock doesn't complain about the attempt.
+	mock.ExpectQuery("SELECT delivery_mode FROM workspaces WHERE id").
+		WillReturnError(context.Canceled)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // simulate the HTTP handler having returned (request ctx dead)
+
+	mode, err := lookupDeliveryMode(ctx, "ws-poll-peer")
+	if err == nil {
+		t.Fatalf("internal#497 regression: lookupDeliveryMode swallowed a context error and returned mode=%q with nil err — this is the exact 5-day silent-misrouting vector", mode)
+	}
+	if mode == models.DeliveryModePush {
+		t.Errorf("internal#497 regression: context error must NOT default to push (got mode=%q)", mode)
+	}
+}
+
 // ==================== a2aClient ResponseHeaderTimeout config ====================
 
 func TestA2AClientResponseHeaderTimeout(t *testing.T) {

workspace-server/internal/handlers/delegation.go

@@ -162,8 +162,32 @@ func (h *DelegationHandler) Delegate(c *gin.Context) {
 		},
 	})
 
-	// Fire-and-forget: send A2A in background goroutine
-	go h.executeDelegation(ctx, sourceID, body.TargetID, delegationID, a2aBody)
+	// Fire-and-forget: send A2A in a background goroutine.
+	//
+	// internal#497 — the goroutine MUST NOT inherit the HTTP request's
+	// cancellation. `ctx` here is c.Request.Context(); the handler returns
+	// 202 a few lines below, which cancels that context immediately. Before
+	// this fix (regression ce2db75f) executeDelegation ran on the
+	// request-scoped ctx, so every DB op + proxy call in the detached
+	// goroutine failed `context canceled` the instant the 202 was written.
+	// That silently broke 100% of A2A peer delegations fleet-wide since
+	// 2026-05-12 (poll-mode peers never got their a2a_receive inbox row;
+	// lookupDeliveryMode swallowed the ctx error and defaulted to push).
+	//
+	// context.WithoutCancel detaches cancellation/deadline while PRESERVING
+	// all context values (trace/correlation/tenant ids that proxyA2ARequest
+	// and the broadcaster read off ctx) — this is the established pattern in
+	// this package (a2a_proxy.go:850, a2a_proxy_helpers.go:525,
+	// registry.go:822). The 30-minute ceiling matches the prior internal
+	// budget executeDelegation used before ce2db75f and the proxy's own
+	// absolute agent-dispatch ceiling (a2a_proxy.go forwardCtx).
+	delegationCtx, cancelDelegation := context.WithTimeout(
+		context.WithoutCancel(ctx), 30*time.Minute,
+	)
+	go func() {
+		defer cancelDelegation()
+		h.executeDelegation(delegationCtx, sourceID, body.TargetID, delegationID, a2aBody)
+	}()
 
 	// Broadcast event so canvas shows delegation in real-time
 	h.broadcaster.RecordAndBroadcast(ctx, string(events.EventDelegationSent), sourceID, map[string]interface{}{

workspace-server/internal/handlers/delegation_test.go

@@ -16,6 +16,65 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// ---------- internal#497 regression: detached goroutine ctx must outlive the handler ----------
+
+// TestDelegate_DetachedContext_SurvivesRequestCancellation pins the
+// load-bearing invariant that regression ce2db75f violated: the context
+// handed to executeDelegation in the fire-and-forget goroutine must NOT be
+// cancelled when the HTTP handler returns 202 (which cancels
+// c.Request.Context()). Before the fix, executeDelegation ran on the
+// request-scoped ctx, so every DB op + proxy call failed `context
+// canceled` the instant the 202 was written — silently breaking 100% of
+// A2A peer delegations fleet-wide since 2026-05-12.
+//
+// This test asserts the exact ctx-derivation contract used by Delegate
+// (context.WithoutCancel(parent) + a timeout budget): the derived context
+// (a) stays alive after the parent is cancelled, and (b) still carries
+// parent values (trace/correlation/tenant ids the downstream proxy +
+// broadcaster read off ctx). It is intentionally DB-free and fast.
+func TestDelegate_DetachedContext_SurvivesRequestCancellation(t *testing.T) {
+	type ctxKey string
+	const traceKey ctxKey = "trace-id"
+
+	// Simulate c.Request.Context() carrying a correlation value.
+	parent, cancelParent := context.WithCancel(
+		context.WithValue(context.Background(), traceKey, "trace-abc-123"),
+	)
+
+	// Exact derivation Delegate uses for the detached goroutine.
+	delegationCtx, cancelDelegation := context.WithTimeout(
+		context.WithoutCancel(parent), 30*time.Minute,
+	)
+	defer cancelDelegation()
+
+	// The HTTP handler "returns 202" → request context is cancelled.
+	cancelParent()
+
+	if err := parent.Err(); err == nil {
+		t.Fatal("precondition: parent context should be cancelled after the handler returns")
+	}
+
+	// (a) Cancellation MUST NOT propagate to the detached context.
+	select {
+	case <-delegationCtx.Done():
+		t.Fatalf("regression: detached delegation ctx was cancelled by the handler returning (err=%v) — executeDelegation would fail every DB op with `context canceled`", delegationCtx.Err())
+	default:
+		// alive — correct
+	}
+
+	// (b) Parent values MUST still be readable (WithoutCancel preserves
+	// values; trace/correlation/tenant ids the proxy + broadcaster use).
+	if got, _ := delegationCtx.Value(traceKey).(string); got != "trace-abc-123" {
+		t.Errorf("detached ctx lost the parent trace value: got %q, want %q", got, "trace-abc-123")
+	}
+
+	// And it still has a real deadline (the 30m budget), so it is not an
+	// unbounded background context.
+	if _, hasDeadline := delegationCtx.Deadline(); !hasDeadline {
+		t.Error("detached ctx must carry the 30-minute timeout budget, but has no deadline")
+	}
+}
+
 // ---------- Delegate: missing target_id → 400 ----------
 
 func TestDelegate_MissingTargetID(t *testing.T) {

workspace-server/internal/handlers/plugins_listing_test.go

@@ -0,0 +1,141 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+)
+
+func TestListRegistry_EmptyDir(t *testing.T) {
+	dir := t.TempDir()
+	h := NewPluginsHandler(dir, nil, nil)
+
+	got := h.listRegistryFiltered("")
+	if len(got) != 0 {
+		t.Errorf("expected empty list, got %d plugins", len(got))
+	}
+}
+
+func TestListRegistry_IgnoresFiles(t *testing.T) {
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "not-a-plugin.txt"), []byte("x"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	h := NewPluginsHandler(dir, nil, nil)
+
+	got := h.listRegistryFiltered("")
+	if len(got) != 0 {
+		t.Errorf("expected empty list (files ignored), got %d", len(got))
+	}
+}
+
+func TestListRegistry_SinglePlugin(t *testing.T) {
+	dir := t.TempDir()
+	pluginDir := filepath.Join(dir, "my-plugin")
+	if err := os.Mkdir(pluginDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(pluginDir, "plugin.yaml"), []byte("name: my-plugin\nversion: 1.0.0\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	h := NewPluginsHandler(dir, nil, nil)
+
+	got := h.listRegistryFiltered("")
+	if len(got) != 1 {
+		t.Fatalf("expected 1 plugin, got %d", len(got))
+	}
+	if got[0].Name != "my-plugin" {
+		t.Errorf("expected name 'my-plugin', got %q", got[0].Name)
+	}
+}
+
+func TestListRegistry_FiltersByRuntime(t *testing.T) {
+	dir := t.TempDir()
+	for _, spec := range []struct{ name, yaml string }{
+		{"runtime-a", "name: runtime-a\nruntimes:\n  - claude-code\n"},
+		{"runtime-b", "name: runtime-b\nruntimes:\n  - hermes\n"},
+		{"universal", "name: universal\nversion: 1.0.0\n"},
+	} {
+		pd := filepath.Join(dir, spec.name)
+		if err := os.Mkdir(pd, 0755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(pd, "plugin.yaml"), []byte(spec.yaml), 0600); err != nil {
+			t.Fatal(err)
+		}
+	}
+	h := NewPluginsHandler(dir, nil, nil)
+
+	// Filter to claude-code: runtime-a matches, universal (no runtimes field)
+	// is always included per supportsRuntime semantics.
+	got := h.listRegistryFiltered("claude-code")
+	if len(got) != 2 {
+		t.Fatalf("expected 2 (runtime-a + universal), got %d: %v", len(got), func() []string {
+			ns := make([]string, len(got))
+			for i, p := range got { ns[i] = p.Name }
+			return ns
+		}())
+	}
+}
+
+func TestListRegistry_PluginWithNoRuntimeDeclarations_AlwaysIncluded(t *testing.T) {
+	dir := t.TempDir()
+	pd := filepath.Join(dir, "universal-plugin")
+	if err := os.Mkdir(pd, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(pd, "plugin.yaml"), []byte("name: universal-plugin\nversion: 1.0.0\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	h := NewPluginsHandler(dir, nil, nil)
+
+	// When plugin declares no runtimes, it should always be included (try-it).
+	got := h.listRegistryFiltered("any-runtime")
+	if len(got) != 1 {
+		t.Errorf("expected 1 plugin (unspecified runtime), got %d", len(got))
+	}
+}
+
+func TestListRegistry_ReadDirError_ReturnsEmpty(t *testing.T) {
+	h := NewPluginsHandler("/nonexistent/path/for/plugins", nil, nil)
+	got := h.listRegistryFiltered("")
+	if len(got) != 0 {
+		t.Errorf("expected empty list on ReadDir error, got %d", len(got))
+	}
+}
+
+func TestListRegistry_HTTPEndpoint(t *testing.T) {
+	dir := t.TempDir()
+	pd := filepath.Join(dir, "test-plugin")
+	if err := os.Mkdir(pd, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(pd, "plugin.yaml"), []byte("name: test-plugin\nversion: 2.0.0\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	h := NewPluginsHandler(dir, nil, nil)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/plugins", nil)
+	h.ListRegistry(c)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+	var plugins []pluginInfo
+	if err := json.Unmarshal(w.Body.Bytes(), &plugins); err != nil {
+		t.Fatalf("failed to parse JSON: %v", err)
+	}
+	if len(plugins) != 1 {
+		t.Errorf("expected 1 plugin, got %d", len(plugins))
+	}
+	if plugins[0].Name != "test-plugin" {
+		t.Errorf("expected name 'test-plugin', got %q", plugins[0].Name)
+	}
+}