## Why
PR descriptions can be visible outside the context used to generate
them. In #23710, a generated description referenced an internal
document, showing that the skill needs an explicit guardrail against
exposing confidential context.
## What changed
- Updated the `codex-pr-body` guidance to prohibit confidential
references, including codenames and OpenAI-internal URLs.
## Motivation
Codex needs a repeatable workflow for updating PR metadata after a pull
request already exists. This is more specific than generic GitHub
handling: the assistant needs to preserve author-provided body content,
explain why the PR exists before listing implementation details, and
describe only the net change under review, including when Sapling stacks
put a PR on top of another PR instead of `main`.
## Changes
- Adds `.codex/skills/codex-pr-body/SKILL.md`.
- Documents how to infer the target PR from the current branch or
commit, including Sapling-specific PR metadata and `sl sl` output.
- Defines the expected PR body update behavior: inspect the existing
body, preserve key content such as images, avoid local absolute paths,
use Markdown formatting, include relevant issue/PR references, and call
out developer docs follow-up only when applicable.
- Captures stacked-PR handling so generated PR text describes the change
between the PR's base and head, rather than unrelated ancestor changes.
## Verification
Not run; this is a Codex skill documentation addition.
Adam Perry @ OpenAI ·
Michael Bolin ·