exec: expose thread source in CLI and TypeScript SDK

[pakrym-oai]

Why

codex exec currently classifies every new thread and fork as user, so integrations using the CLI or TypeScript SDK cannot attribute agent work to the feature that initiated it. The app-server protocol and Python SDK already support caller-supplied thread sources.

What changed

• Add codex exec --thread-source <SOURCE> for new threads and forks, including flags supplied after the fork subcommand.
• Add threadSource?: string to the TypeScript SDK's ThreadOptions and forward it when the SDK creates a thread.
• Preserve the existing user default and keep resumed threads' persisted source unchanged.
• Verify custom sources are persisted in rollout metadata and included in outgoing x-codex-turn-metadata independently of the existing originator override.

codex exec --thread-source automated_review "Review the current changes"

const thread = codex.startThread({ threadSource: "automated_review" });

Verification

• just test -p codex-exec --lib (61 tests)
• just test -p codex-exec --test all exec_fork_creates_distinct_threads_with_and_without_a_prompt
• just test -p codex-exec --test all supports_originator_override
• TypeScript SDK subprocess tests (14 tests), focused typechecking, and live SDK integration coverage for source attribution, resume behavior, and the existing originator header.

Documentation

Update the Codex CLI reference and TypeScript SDK documentation to cover --thread-source and ThreadOptions.threadSource.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-22T23:49:33.137668Z	da2cd2e	New commits
🔒 Security Review	✅ Completed 2026-08-22T23:50:50.294435Z	da2cd2e	New commits

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 8daa0e3b54

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Test the effective thread-source default

This assertion only checks the statically implied absence of the optional clap field; it does not exercise the new run_main fallback that maps absence to ThreadSource::User, so a regression in the user-visible default would still pass. Replace it with behavioral coverage that starts a thread without the flag and verifies that its persisted or request source is user.

AGENTS.md reference: AGENTS.md:L29-L30

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