Sync thread renames to the provider session (Claude Code custom-title)

[vladknysh]

When I rename a thread in T3 Code, the name stays in T3. I named a Claude thread "icon-ambiguity", then went to continue it with claude --resume in a terminal. The picker listed it as "Icon helper documentation", the title Claude generated, so I had to dig the session UUID out of T3 to find it.

Proposed behavior

A manual rename in T3 also renames the provider session behind the thread, when the provider has a way to do it. The name I type shows up in that provider's own session list.

Smallest mechanism for Claude

The Agent SDK already does this. renameSession(sessionId, title, { dir }) appends a {"type":"custom-title","customTitle":"...","sessionId":"..."} record to the session JSONL, the same record /rename writes. In Claude Code's session metadata, customTitle beats aiTitle even when an ai-title record comes later in the file. I checked this on a local transcript with getSessionInfo.

T3 already stores the session id in provider_session_runtime.resume_cursor_json as resume, so this works when no session is live too. A rough shape:

• An optional adapter method, something like renameProviderSession(threadId, title).
• ProviderCommandReactor calls it on thread.meta-updated when titleState.source is "manual".
• It uses the same seed filter the OpenCode session.create path already uses, so the first-prompt seed the web client writes as "manual" doesn't get pushed as a rename.
• Before the first turn, the SDK's title option on query() would cover it, the same way T3 passes a manual title to OpenCode at session.create.

Per adapter:

• Claude: supported, via renameSession.
• Codex: supported. The app server has thread/name/set, and T3 already mirrors thread/name/updated the other way.
• OpenCode: supported. session.update accepts title. Today T3 only sends a title at session.create.
• Cursor, Grok, Antigravity: not through ACP. ACP has session_info_update from agent to client, but no method for the client to set a title.

Related

• Mirror Claude Code's /rename into the thread title, like Codex and OpenCode already do #9588 asks for the reverse: Claude Code /rename into the T3 title. Together they make renames sync both ways for Claude, the way they already do for OpenCode.
• [Bug]: Imported Claude Code threads drop the user's renamed title (custom-title / customTitle) #12276: imported Claude threads ignore customTitle. Once T3 writes custom-title records, the importer should read them back.

Open questions

• Should T3 change provider-owned session state at all, even through the provider's own API, or should this be a setting?
• If Claude Code is running that session in a terminal at the same time, can the running process write its in-memory title back over T3's record? Claude Code does re-append title records during a session.
• Should generated titles sync too, or only manual renames? Syncing generated ones would replace Claude's own ai-title with T3's.
• If both directions land, what stops a rename from bouncing back and forth?

Written on Vlad's behalf by an AI agent (Claude Opus 5.5 via Claude Code in T3 Code), reviewed by Vlad before posting.

[nkoynov]

The same gap exists for OpenCode 2 threads, with a cost on top. T3 creates the OpenCode session without a title, so on the first prompt OpenCode runs its own title model (a separate request on its small model), and opencode's session list shows that title instead of the thread's name in T3.

OpenCode only titles a root session while its title is unset, so the OpenCode side is small: create the session with the thread's current title, and before a turn update the session's title if the thread was renamed since. That covers manual renames and T3's generated title replacing the seed (both reach OpenCode at the next turn, not instantly). An empty title is never sent, since OpenCode treats that as "generate one". Claude isn't touched.

I have it on a branch: nkoynov/t3code fix/opencode-session-title. On nightly 2849 with OpenCode 2.0.25, each new OpenCode thread made one extra tool-less title run on its session (two threads, two runs), and both OpenCode titles differed from T3's. With the same behaviour applied locally, the extra run was gone, the names matched, and a rename in T3 showed up in OpenCode.

Would a PR limited to the OpenCode 2 adapter be welcome? I'll open it linked here so the change is easy to look at; happy to close it if you'd rather go another way.

Model: Claude Opus 5.5 (1M). Harness: OpenCode in T3 Code.