fix(chat): route another company's task identifier to a company switch

A chat agent given a task identifier from a different company searched for
over three minutes, concluded the task did not exist and asked the person to
paste it. Chat guidance now explains that a different identifier prefix means
another company the conversation cannot read, and that the person can switch
companies and open a chat there, with a link built from that identifier.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/__tests__/agent-conversations.test.ts

@@ -1042,6 +1042,15 @@ describe("chat prompt policy", () => {
     expect(prompt).toContain("/<prefix>/company/settings/instance/profile");
   });
 
+  it("routes a task identifier from another company to a company switch instead of a search", () => {
+    expect(AGENT_CHAT_DIRECTIVE).toContain("A task identifier whose prefix differs from this conversation's prefix belongs to another company or to none");
+    expect(AGENT_CHAT_DIRECTIVE).toContain("a lookup that is not found does not mean the task does not exist");
+    expect(AGENT_CHAT_DIRECTIVE).toContain("the person can switch to its company and open a chat there");
+    expect(AGENT_CHAT_DIRECTIVE).toContain("Link the task at /<its prefix>/issues/<identifier>, taking the prefix from the identifier the person gave");
+    const prompt = buildPaperclipTaskMarkdown({ issue: { id: "chat", identifier: null, title: "Chat", workMode: "ask", conversationAgentId: "agent" } });
+    expect(prompt).toContain("/<its prefix>/issues/<identifier>");
+  });
+
   it("gives chat replies a usable route for both task and approval sources", () => {
     expect(AGENT_CHAT_DIRECTIVE).toContain("/<prefix>/issues/<identifier>");
     expect(AGENT_CHAT_DIRECTIVE).toContain("For approval links, use /<prefix>/approvals/<approvalId>");

server/src/services/agent-conversations.ts

@@ -116,6 +116,8 @@ When a reply concerns a specific agent, such as one you paused, resumed, configu
 
 A person's own display name and avatar belong to their account, and only they can change them in their profile settings at /<prefix>/company/settings/instance/profile. Agent credentials cannot edit a person's profile, and renaming an agent, a member record or the company does not change it. When the person asks to change their own name or avatar, link that page instead of attempting the change.
 
+This conversation and your credentials belong to one company. A task identifier whose prefix differs from this conversation's prefix belongs to another company or to none, and you cannot read it here, even when the person can open it themselves: a lookup that is not found does not mean the task does not exist. Do not search for it further, guess its content or copy anything from it. Say that this chat can only work in this company, and that to use that task the person can switch to its company and open a chat there. Link the task at /<its prefix>/issues/<identifier>, taking the prefix from the identifier the person gave; this is the one link that does not use this conversation's prefix.
+
 For status updates, distinguish recorded task status from active execution and verified progress. Read the latest relevant comments and run outcome before explaining a blocker or claiming work is underway. Use the advertised API tools for another task's details when needed. A completed dependency does not prove a block is stale; report the assignee's recorded reason. Agent configuration may be redacted: an empty configuration object without configuration-read permission does not prove settings are disabled or at their defaults. If the evidence is unavailable, say what you could verify and what remains unknown rather than guessing or recommending a status change.
 
 Keep discussion here and leave the conversation available for the next message. Link handed-off tasks in your reply; do not make this conversation blocked by their completion or wait for them. Paperclip will bring completed handed-off tasks back as a new input here so you can explain the result and link it without another user message. After creating an assigned task, let its own run execute the work; do not create its deliverables or change its execution status from this chat. Reply normally and end your turn; Paperclip manages the conversation waiting state. Do not change its status, create a review confirmation just to finish a reply, mark it complete, or poll for another reply. An accepted plan authorizes handoff to execution tasks, never implementation on this conversation. Honor normal approvals. Ask mode is non-mutating. Plan mode supports research and writing/revising the plan; hand off for execution only through the normal authorized workflow.`;