diff --git a/server/src/__tests__/agent-conversations.test.ts b/server/src/__tests__/agent-conversations.test.ts
index 7032059712c..264670e4b82 100644
--- a/server/src/__tests__/agent-conversations.test.ts
+++ b/server/src/__tests__/agent-conversations.test.ts
@@ -994,6 +994,13 @@ describe("chat prompt policy", () => {
     expect(prompt).toContain("/<prefix>/agents/<urlKey or id>");
   });
 
+  it("says how to read the company link prefix from a task identifier so agent links are not guessed", () => {
+    expect(AGENT_CHAT_DIRECTIVE).toContain("The company prefix is the part of a task identifier before its final hyphen and number: for task RUN-1 the prefix is RUN.");
+    expect(AGENT_CHAT_DIRECTIVE).toContain("Never build a prefix from the company name");
+    const prompt = buildPaperclipTaskMarkdown({ issue: { id: "chat", identifier: "RUN-1", title: "Chat", workMode: "ask", conversationAgentId: "agent" } });
+    expect(prompt).toContain("for task RUN-1 the prefix is RUN");
+  });
+
   it("asks which record is meant before changing one of several matches", () => {
     expect(AGENT_CHAT_DIRECTIVE).toContain("matches several records you can access and nothing in the conversation selects one, ask which one before changing any of them");
     expect(AGENT_CHAT_DIRECTIVE).toContain("link each candidate");
diff --git a/server/src/services/agent-conversations.ts b/server/src/services/agent-conversations.ts
index 73c09dade49..44a15e4352d 100644
--- a/server/src/services/agent-conversations.ts
+++ b/server/src/services/agent-conversations.ts
@@ -110,7 +110,7 @@ Create ordinary assigned tasks; this conversation is never a parent. Choose the
 
 For review or follow-up tasks, include the existing source materials the assignee needs, not just task identifiers or a rubric. Read the source task's saved documents and comments, then copy the relevant existing content into the handoff or attach resources the recipient can actually read. A new task's tools may only expose its own documents and history. Supplying existing source material is coordination, not creating the assigned deliverable.
 
-For task links, use the company-prefixed relative path /<prefix>/issues/<identifier>, deriving the prefix from the returned task identifier. For approval links, use /<prefix>/approvals/<approvalId> with the same company prefix and the returned approval id, so the person can open the approval to decide it. An absolute URL is appropriate only when its actual origin was supplied by the platform. Never invent a hostname for a Paperclip link. For an execution run, link /<prefix>/agents/<agentId>/runs/<runId> using the run's returned agentId. Issue run listings (GET /api/issues/{id}/runs) return the run ID as runId; use id only from responses that return the run itself, such as GET /api/heartbeat-runs/{runId}. Run listings return agent IDs, not names: read the agent and name it rather than showing a raw ID.
+For task links, use the company-prefixed relative path /<prefix>/issues/<identifier>. The company prefix is the part of a task identifier before its final hyphen and number: for task RUN-1 the prefix is RUN. This conversation's own task identifier gives it, and every company link below (tasks, approvals, runs, agent profiles) uses that same prefix. Never build a prefix from the company name, a slug, a hostname or a file path. For approval links, use /<prefix>/approvals/<approvalId> with the same company prefix and the returned approval id, so the person can open the approval to decide it. An absolute URL is appropriate only when its actual origin was supplied by the platform. Never invent a hostname for a Paperclip link. For an execution run, link /<prefix>/agents/<agentId>/runs/<runId> using the run's returned agentId. Issue run listings (GET /api/issues/{id}/runs) return the run ID as runId; use id only from responses that return the run itself, such as GET /api/heartbeat-runs/{runId}. Run listings return agent IDs, not names: read the agent and name it rather than showing a raw ID.
 
 When a reply concerns a specific agent, such as one you paused, resumed, configured, or reported on, link its profile at /<prefix>/agents/<urlKey or id> using the agent's returned urlKey or id. A profile link is not a mention: use agent:// only when you intend to notify that agent.