fix(sessions): reject thread send targets

CHANGELOG.md

@@ -27,6 +27,7 @@ Docs: https://docs.openclaw.ai
 - Telegram: inherit the process DNS result order for Bot API transport and downgrade recovered sticky IPv4 fallback promotions to debug logs, while keeping pinned-IP escalation warnings visible. Fixes #75904. Thanks @highfly-hi and @neeravmakwana.
 - Web search/MiniMax: allow `MINIMAX_OAUTH_TOKEN` to satisfy MiniMax Search credentials, so OAuth-authorized MiniMax Token Plan setups do not need a separate web-search key. Fixes #65768. Thanks @kikibrian and @zhouhe-xydt.
 - Providers/MiniMax: derive Coding Plan usage polling from the configured MiniMax base URL, so global setups no longer query the CN usage host. Fixes #65054. Thanks @sixone74 and @Yanhu007.
+- Sessions: reject `sessions_send` targets that resolve to thread-scoped chat sessions, so inter-agent coordination cannot be injected into active human-facing Slack or Discord threads. Fixes #52496. Thanks @barry-p5cc.
 - Subagents: honor `sessions_spawn` with `expectsCompletionMessage: false` by skipping parent completion handoff delivery while still running child cleanup. Fixes #75848. Thanks @alfredjbclaw.
 - Gateway/logging: keep deferred channel startup logs on the subsystem logger, so Slack, Discord, Telegram, and voice-call startup messages keep timestamped prefixes. Thanks @vincentkoc.
 - Replies/typing: keep typing alive for queued follow-up messages that are genuinely waiting behind an active run, instead of making chat surfaces look idle while work is queued. Fixes #65685. Thanks @papag00se.

docs/concepts/session-tool.md

@@ -93,6 +93,11 @@ the response:
   immediately.
 - **Wait for reply:** set a timeout and get the response inline.
 
+Thread-scoped chat sessions, such as Slack or Discord keys ending in
+`:thread:<id>`, are not valid `sessions_send` targets. Use the parent channel
+session key for inter-agent coordination so tool-routed messages do not appear
+inside an active human-facing thread.
+
 Messages and A2A follow-up replies are marked as inter-session data in the
 receiving prompt (`[Inter-session message ... isUser=false]`) and in transcript
 provenance. The receiving agent should treat them as tool-routed data, not as a

src/agents/tool-description-presets.ts

@@ -28,6 +28,7 @@ export function describeSessionsHistoryTool(): string {
 export function describeSessionsSendTool(): string {
   return [
     "Send a message into another visible session by sessionKey or label.",
+    "Thread-scoped chat sessions are rejected; target the parent channel session for inter-agent coordination.",
     "Use this to delegate follow-up work to an existing session; waits for the target run and returns the updated assistant reply when available.",
   ].join(" ");
 }

src/agents/tools/sessions-send-tool.ts

@@ -1,6 +1,7 @@
 import crypto from "node:crypto";
 import { Type } from "typebox";
 import { isRequesterParentOfBackgroundAcpSession } from "../../acp/session-interaction-mode.js";
+import { parseSessionThreadInfoFast } from "../../config/sessions/thread-info.js";
 import type { OpenClawConfig } from "../../config/types.openclaw.js";
 import { callGateway } from "../../gateway/call.js";
 import { formatErrorMessage } from "../../infra/errors.js";
@@ -254,6 +255,15 @@ export function createSessionsSendTool(opts?: {
           sessionKey: displayKey,
         });
       }
+      if (parseSessionThreadInfoFast(resolvedKey).threadId) {
+        return jsonResult({
+          runId: crypto.randomUUID(),
+          status: "error",
+          error:
+            "sessions_send cannot target a thread session for inter-agent coordination. Use the parent channel session key instead.",
+          sessionKey: displayKey,
+        });
+      }
 
       // Capture the pre-run assistant snapshot before starting the nested run.
       // Fast in-process test doubles and short-circuit agent paths can finish

src/agents/tools/sessions.test.ts

@@ -658,6 +658,62 @@ describe("sessions_send gating", () => {
     expect(result.details).toMatchObject({ status: "forbidden" });
   });
 
+  it("rejects direct thread session targets before dispatching an agent run", async () => {
+    loadConfigMock.mockReturnValue({
+      session: { scope: "per-sender", mainKey: "main" },
+      tools: {
+        agentToAgent: { enabled: false },
+        sessions: { visibility: "all" },
+      },
+    });
+    const threadSessionKey = "agent:main:slack:channel:C123:thread:1710000000.000100";
+    const tool = createMainSessionsSendTool();
+
+    const result = await tool.execute("call-thread-target", {
+      sessionKey: threadSessionKey,
+      message: "hi",
+      timeoutSeconds: 0,
+    });
+
+    expect(result.details).toMatchObject({
+      status: "error",
+      sessionKey: threadSessionKey,
+    });
+    expect((result.details as { error?: string } | undefined)?.error ?? "").toContain(
+      "cannot target a thread session",
+    );
+    expect(callGatewayMock).not.toHaveBeenCalled();
+  });
+
+  it("rejects label targets that resolve to canonical thread sessions", async () => {
+    loadConfigMock.mockReturnValue({
+      session: { scope: "per-sender", mainKey: "main" },
+      tools: {
+        agentToAgent: { enabled: false },
+        sessions: { visibility: "all" },
+      },
+    });
+    const threadSessionKey = "agent:main:discord:channel:123456:thread:987654";
+    callGatewayMock.mockResolvedValueOnce({ key: threadSessionKey });
+    const tool = createMainSessionsSendTool();
+
+    const result = await tool.execute("call-thread-label", {
+      label: "active thread",
+      message: "hi",
+      timeoutSeconds: 0,
+    });
+
+    expect(result.details).toMatchObject({
+      status: "error",
+      sessionKey: threadSessionKey,
+    });
+    expect((result.details as { error?: string } | undefined)?.error ?? "").toContain(
+      "cannot target a thread session",
+    );
+    expect(callGatewayMock).toHaveBeenCalledTimes(1);
+    expect(callGatewayMock.mock.calls[0]?.[0]).toMatchObject({ method: "sessions.resolve" });
+  });
+
   it("does not reuse a stale assistant reply when no new reply appears", async () => {
     const tool = createMainSessionsSendTool();
     let historyCalls = 0;