docs(agents): Fix defects found by dry-running the PR skill

Ran fresh agents through "create a PR" and "create a stacked PR" against
the deduped docs, stopping each before the first mutating action. Both
paths loaded the intended files, but four defects surfaced:

- SKILL.md named stacked-prs.md the source of truth for branch naming,
  which that file never covered. Corrected to title naming; the branch
  rule stays in Step 1, where the branch is created.
- Four passages referenced the collection branch PR, but no step ever
  opened it. Added next to the branch creation, with its title and
  merge-reminder exceptions.
- The PR-description editing rule was stated three times and had already
  drifted. It now lives once in SKILL.md, which both the standalone and
  stacked paths read, and stacked-prs.md points back to it.
- AGENTS.md rule 7 told agents to propose but not execute a commit while
  the create-java-pr skill commits, pushes, and opens the PR, leaving two
  terminal states for one request. Scoped rule 7 to implementation work.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: runningcode

.claude/skills/create-java-pr/SKILL.md

@@ -8,7 +8,7 @@ description: Create a pull request in sentry-java. Use when asked to "create pr"
 Prepare local changes and create a pull request for the sentry-java repo.
 
 **For stacked PRs:** read `references/stacked-prs.md` before proceeding. It is the source of truth for
-stack structure, branch and title naming, stack list format, and merge strategy.
+stack structure, title naming, stack list format, and merge strategy.
 
 ## Step 0: Determine PR Type From Git Branch Context
 
@@ -152,11 +152,7 @@ Skip this step for standalone PRs.
 
 After creating the PR, update the PR description on **every other PR in the stack — including the collection branch PR** — so all PRs have the same up-to-date stack list. Follow the format and commands in `references/stacked-prs.md` § "Stack List in PR Description".
 
-**Important:** When updating PR bodies, never use shell redirects (`>`, `>>`) or pipes (`|`) or compound commands (`&&`). These create compound shell expressions that won't match permission patterns. Instead:
-- Use `gh pr view <NUMBER> --json body --jq '.body'` to get the body (output returned directly)
-- Use the `Write` tool to save it to a temp file
-- Use the `Edit` tool to modify the temp file
-- Use `gh pr edit <NUMBER> --body-file /tmp/pr-body.md` to update
+Edit each body using the procedure in § "Editing PR Descriptions" below.
 
 ## Step 6: Update Changelog
 
@@ -208,8 +204,14 @@ git push
 
 ### No changelog needed
 
-If no changelog entry is needed, add `#skip-changelog` to the PR description to disable the changelog CI check:
+If no changelog entry is needed, append `#skip-changelog` to the end of the PR description to disable
+the changelog CI check, using the procedure in § "Editing PR Descriptions" below.
 
-1. Get the current body: `gh pr view <PR_NUMBER> --json body --jq '.body'`
-2. Use the `Write` tool to save the output to `/tmp/pr-body.md`, appending `\n#skip-changelog\n` at the end
-3. Update: `gh pr edit <PR_NUMBER> --body-file /tmp/pr-body.md`
+## Editing PR Descriptions
+
+Do not use shell redirects (`>`, `>>`), pipes (`|`), or compound commands (`&&`, `||`). These create
+compound shell expressions that won't match permission patterns. Instead:
+
+1. Read the body with `gh pr view <PR_NUMBER> --json body --jq '.body'` (output is returned directly)
+2. Use the `Write` tool to save it to `/tmp/pr-body.md`, and the `Edit` tool to modify it
+3. Update with `gh pr edit <PR_NUMBER> --body-file /tmp/pr-body.md`

.claude/skills/create-java-pr/references/stacked-prs.md

@@ -24,6 +24,10 @@ Create it with an empty commit, so GitHub allows opening a PR:
 git commit --allow-empty -m "collection: <topic>"
 ```
 
+Push it and open its PR against `main` right away — it is the PR the whole stack is eventually
+squash-merged through, and it carries the stack list like every other PR. Give it a plain title
+(`<type>(<scope>): <Topic>`, no `[<Topic> <N>]` bracket) and no merge method reminder.
+
 ## Rules That Will Destroy a Stack If Broken
 
 **Never update the collection branch yourself.** Never merge, fast-forward, or push stack branch
@@ -78,11 +82,5 @@ the description.
 > ⚠️ **Merge this PR using a merge commit** (not squash). Only the collection branch is squash-merged into main.
 ```
 
-## Editing PR Descriptions
-
-Do not use shell redirects (`>`, `>>`), pipes (`|`), or compound commands (`&&`, `||`). These create
-compound shell expressions that won't match permission patterns. Instead:
-
-1. Read the body with `gh pr view <PR_NUMBER> --json body --jq '.body'` (output is returned directly)
-2. Use the `Write` tool to save it to `/tmp/pr-body.md`, and the `Edit` tool to modify it
-3. Update with `gh pr edit <PR_NUMBER> --body-file /tmp/pr-body.md`
+Updating every PR's stack list means editing several descriptions — follow the procedure in
+`SKILL.md` § "Editing PR Descriptions".

AGENTS.md

@@ -98,7 +98,7 @@ make systemTest
 4. **High-level communication**: Give high-level explanations of changes made, not step-by-step descriptions
 5. **Simplicity first**: Make every task and code change as simple as possible. Avoid massive or complex changes. Impact as little code as possible.
 6. **Format and regenerate**: Once done, format code and regenerate .api files: `./gradlew spotlessApply apiDump`
-7. **Propose commit**: As final step, git stage relevant files and propose (but not execute) a single git commit command
+7. **Propose commit**: As final step, git stage relevant files and propose (but not execute) a single git commit command. This applies to implementation work; when the task is to open a PR, the `create-java-pr` skill takes over from here and does commit, push, and open it.
 
 ## Repository Skills