## Summary
- reuse the shared shell read parser for implicit skill doc invocation
detection
- add regression coverage for `nl -ba .../SKILL.md`
## Why
Desktop could render `Read User Context skill` for reads recognized by
the shared command parser, while implicit `skill_invocation` analytics
used a separate reader allowlist and missed cases such as `nl`.
## Validation
- `HOME=/private/tmp/codex-core-skills-home-pr
PATH=/Users/alexsong/.cache/cargo-home/bin:$PATH
CARGO_HOME=/Users/alexsong/.cache/cargo-home just test -p
codex-core-skills`
- `git diff --cached --check`
- `just fmt` attempted; Rust formatting completed, but the Python
formatters could not download uncached Ruff wheels because
`files.pythonhosted.org` is blocked in this sandbox.
- `bazel mod deps --lockfile_mode=update/error
--repo_env=ASPECT_TOOLS_TELEMETRY= --repo_env=DO_NOT_TRACK=1` evaluated
the module graph and produced no `MODULE.bazel.lock` diff, but Bazel
crashed on sandboxed `sysctl` during exit.
## Why
We're moving exec-server to use PathUri for its internal path
representations.
## What
Move `ExecutorFileSystem` APIs to use `PathUri` instead of
`AbsolutePathBuf`. Future changes will convert higher-level parts of
exec-server.
## Why
`codex-core` currently owns the generic contextual-fragment trait and
several reusable fragment implementations. That makes it harder for
other crates to share the same host-owned model-input abstraction
without depending on all of `codex-core`.
This change extracts the reusable fragment machinery into a small
`codex-context-fragments` crate so future extension and skills work can
depend on the fragment abstraction directly.
## What Changed
- Added the `codex-context-fragments` crate with:
- `ContextualUserFragment`
- `FragmentRegistration` / `FragmentRegistrationProxy`
- additional-context fragment types
- Moved `SkillInstructions` into `codex-core-skills`, since
skill-specific rendering belongs with skills rather than generic core
context machinery.
- Kept `codex-core` re-exporting the fragment types it still uses
internally, so existing call sites keep the same shape.
- Updated Cargo and Bazel workspace metadata for the new crate.
## Verification
- `cargo metadata --locked --format-version 1 --no-deps`
- `just bazel-lock-update`
- `just bazel-lock-check`
Cap the model-visible skills section to a small share of the context
window, with a fallback character budget, and keep only as many implicit
skills as fit within that budget.
Emit a non-fatal warning when enabled skills are omitted, and add a new
app-server warning notification
Record thread-start skill metrics for total enabled skills, kept skills,
and whether truncation happened
---------
Co-authored-by: Matthew Zeng <mzeng@openai.com>
Co-authored-by: Codex <noreply@openai.com>
## Summary
- move skill loading and management into codex-core-skills
- leave codex-core with the thin integration layer and shared wiring
## Testing
- CI
---------
Co-authored-by: Codex <noreply@openai.com>