Overlap executor skill reads with namespace discovery

[jif-oai]

Why

Environment skill discovery needs two independent pieces of information:

• plugin namespaces from plugin.json files; and
• skill metadata from each SKILL.md file.

Today these happen in sequence. Codex waits for every plugin namespace lookup to finish before it starts reading any skill files. On a remote executor, that creates an avoidable network-latency barrier.

before: walk -> namespace lookups -> skill reads -> build catalog
after:  walk -> namespace lookups ─┐
             -> skill reads ───────┴-> build catalog

What changes

• Read and parse skill files without waiting for plugin namespace discovery.
• Resolve root and nested plugin namespaces concurrently.
• Join both results only when constructing the final qualified skill names.
• Keep the existing 64-skill concurrency bound, output ordering, warnings, metadata behavior, and namespace rules.

Testing

The regression test makes plugin manifest lookup wait until a SKILL.md read has started. The old serialized pipeline would time out; the new pipeline completes and still returns the correctly namespaced skill.

just test -p codex-core-skills passes all 111 tests.

Out of scope

This does not add an exec-server endpoint, batch filesystem calls, or reduce the number of files transferred. A frontmatter-only read or server-side skill catalog can remain a separate follow-up if benchmarks show that transferred bytes are the next bottleneck.

[jif-oai]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Swish!

Reviewed commit: 8dd35bbdc2

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".