Let Claude threads on different machines message each other

[tjementum]

Let Claude threads on different machines message each other

Letting Claude threads on different machines message each other would make more powerful setups possible, where fleets of agents work together (Claude Code sessions message each other). For example, I run an agent harness where fleets of agents build large systems together, across machines. Each feature has a T3 Code thread as its lead, and another thread builds the harness itself. The agents talk to each other in real time: when a feature lead hits a harness bug, it messages the harness thread, gets the fix, and carries on, without me relaying anything.

Rather than a pull request, I've written this so a coding agent can follow it as is, since you know how T3 is built and tested much better than I do.

Background

Claude Code's cross-session messaging already supports this: ListAgents finds sessions and SendMessage messages them, over a local socket on the same machine and over Remote Control across machines.

In T3 this already works on one machine; I tested it. Across machines it doesn't:

1. A thread on another machine can't be found. T3 never enlists a Claude thread's session in Remote Control, and both ends need it. Today the only way across is a relay through plain Claude Code sessions, which works but is slow and fragile.

2. The session name doesn't follow the thread. Sessions get generated names, so T3 threads in one repository look alike in ListAgents:

   myproject-ec [0cf449]  ·  interactive  ·  idle
   myproject-75 [670cbc]  ·  interactive  ·  idle
   

Suggested Approach

1. Enlist Claude threads in Remote Control

• Follow the user's Claude Code setting Enable Remote Control for all sessions (remoteControlAtStartup). That setting only connects interactive sessions, so T3 has to start Remote Control itself.
• @anthropic-ai/claude-agent-sdk 0.3.276 (T3's locked version) has an untyped Query.enableRemoteControl(enabled, name?, options?). Call it with the thread title right after query(...) in ClaudeAgentSdkQueryRunner.open (apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts, around line 632).
• If it can't start, for example without a claude.ai sign-in, log it and carry on. It never fails the turn.

2. The session name follows the thread title

• Pass the thread title as Options.title (sdk.d.ts:2320) and as the Remote Control name.
• On a thread rename (thread.metadata.update, thread.title.regeneration.complete), call the untyped Query.renameSession(title) on the live session.

Acceptance Criteria

• With the setting on, a thread shows up under its title in ListAgents of a thread on another machine, and SendMessage starts a turn in it, visible in T3, with no relay.
• With the setting off, nothing changes.
• Renaming a thread renames its session.
• No other provider changes.

Nice to Have: Reconnect Remote Control

In my experience a session can lose Remote Control mid-way, for example after its Claude account changes, and nothing reconnects it. It would be nice if T3 reconnected it, or supported /remote-control in a thread.

Outline
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[TKIPisalegacycipher]

Also really hoping for this. I had a workflow planned that relied specifically on claude's remote-control, but since T3 can't do it, the approach is dead in the water.

To be clear, this is different from T3 Connect. The specific requirement is not Claude's remote-control per se, it's the ability for an agent running in an environment to talk directly to an agent running in a different environment. E.g., I'm developing a Windows app using T3 on my dev box, and I want it to run GUI tests on a VM that's running the app I'm building. I don't care or mind if T3 has its own implementation of that capability, as long as I can do it.

[zainmitchell]

Update 2026-10-28: the native messaging preview I shared here is superseded. Linked environments, which let agents on one machine launch, message, wait on and stop threads on another, now ship in official T3 Code nightly v0.1.4-nightly.20261028.3824 and later as a Labs beta (guide). Please use that instead of the preview. That is T3's own linked-environment path; I'm not claiming it supports Claude Remote Control itself or the ListAgents/SendMessage flow requested here.