Copy a thread's provider thread ID (OpenCode session, Claude Code session, Codex thread)

[MaxAnderson95]

Problem

T3 Code lets you copy its own internal thread ID, but gives you no way to copy or quickly look up the underlying provider's ID for the same conversation: the OpenCode session ID, the Claude Code session ID, the Codex thread ID. I need that ID to pick a conversation up in the provider's own CLI (opencode -s <id>, claude --resume <id>, codex resume <id>), to find it in the provider's history or logs, and to hand it to other tools that only know the provider's ID. Today I either read statev2.sqlite or ask the agent what its session ID is.

The server already has it. Every provider thread stores nativeThreadRef, and every V2 adapter reports one. It just never reaches a client or an MCP tool.

Proposal

• Thread menu: add a third item to the Copy submenu, after Path/Branch and Thread ID, labelled {Provider} Thread ID ("OpenCode Thread ID", "Claude Thread ID", "Codex Thread ID"). It is hidden until the provider reports an ID, and it copies the active provider thread's ID. "Thread" is T3's term, so the label uses it for every provider.
• MCP: t3_thread_read and t3_thread_list already return the T3 thread ID. Add nativeThread: { driver, threadId } | null next to it, so an agent can answer "what is your session ID?" without guessing.

Both read one new optional field on the thread shell, activeNativeThreadRef, which the server derives from the active provider thread the same way it derives goal.

Prototype

I built this as a first pass in #23761, with before/after screenshots and a prompt that re-creates the change, in case you'd rather build it yourselves than review my branch. I opened the PR before getting approval, so close or rework it however suits you.

Open questions:

• Is the thread menu the right place, or would you rather put this in the thread details card?
• Mobile is left out of the PR. Do you want mobile parity in the same change or as a follow-up?
• Claude Code files sessions by working directory, so claude --resume <id> only works from the thread's directory. Is a bare ID still useful enough, or should the copy include more context for Claude?

Related: #17593 asks for provider session IDs in a read-only thread listing for local tools. This covers the UI and MCP side of that request, but not a CLI listing.