A supported way for agents and scripts to list model ids

[t3dotgg]

Problem

To pick a model for a new thread or a script, an agent needs the exact model id. T3 Code has no supported way to list them. One agent searched an 871 KB provider models file with grep to find a Codex model id. This gets more important when t3 thread start --model (#12504) lands.

The server already has the answer. Each provider status carries the model list that the model picker shows.

Proposal

t3 models [--provider <instance>] [--json]

It prints the models T3 Code accepts, grouped by provider instance:

claudeAgent  claude-opus-5    Claude Opus 5    default
claudeAgent  claude-sonnet-5  Claude Sonnet 5

• Reads the running server's provider status, the same source as the model picker. Only enabled, installed instances.
• --json prints { providerInstanceId, slug, name, isDefault }[] for scripts.
• Prints the same ids that t3 thread start --model accepts.

Decisions needed

1. Surface. CLI only, an MCP tool on the t3-code server (for example list_models), or both? The MCP tool also reaches agents that have no shell on the server host.
2. Which models. Only what the picker shows, or also hidden and custom models?
3. No server running. Fail, or read the cached provider status?
4. Detail. Ids only, or also aliases, context-window variants, and effort options?

Related

• feat(cli): add t3 thread start and send to drive threads from scripts #12504 adds t3 thread start --model.
• feat(tools): thread metadata tooling #13305 exposes the calling thread's own model through get_thread_metadata.

Written with Claude Opus 5.5 in Claude Code.

[juliusmarminge]

Thanks for making the model-discovery problem concrete. The orchestrator V2 work has now merged in #2829.

V2 provides orchestrator_capabilities on the built-in MCP server. It returns provider instances and their current model IDs from the same live catalog as the composer, including custom models. This implements the MCP option discussed here; it does not add a t3 models shell command.

Closing this as delivered. If a specific part is still missing in a build containing V2, please open a focused follow-up with the provider/version and the behavior you are seeing.