fix(codex): delegate_task children start as Codex subagents - #36525

Eligibility
Delegated Codex children now start with subagent classification so their MCP calls carry the appropriate source. Ordinary threads, identifier formats and runtime policies remain unchanged, keeping the change narrowly scoped.

Additional Thinking

Your Custom Policy

Default criteria apply. The change corrects internal classification of explicitly delegated children rather than changing a product default, so the product-default restriction is not triggered. No diagnostic-suppression directive is added or broadened in the assessed diff.

Code

Delegated-task thread IDs are recognized by their existing prefix, and only those Codex thread/start requests gain threadSource: "subagent", allowing child MCP calls to be identified as subagent calls. ID encoding, ordinary thread startup, model selection and runtime-policy parameters remain unchanged. Two customer-ignored files were excluded from assessment.

Review Context

Author juliusmarminge is a repository admin and ping-devs member; no path-ownership requirement was supplied. There are no unresolved review comments or supplied correctness findings. Supplied agents are skipped or unknown, not passing evidence; no applicable check prerequisite was supplied.

Verdict

The change is narrowly confined to classifying already-delegated Codex children, preserves identifiers and existing runtime policies, and leaves ordinary threads unchanged. No obvious material exposure or product decision requires human judgment.

Notes:
No code owners found in target merge base 56fd98b

Agent Credits: 30 credits
Approvability runs at a flat rate of 30 credits whenever the agent is asked for a verdict.