docs: remove "same-repo only" limit from push-to-pull-request-branch, document cross-repo setup

docs/src/content/docs/reference/cross-repository.md

@@ -109,6 +109,12 @@ When `allowed-repos` is specified:
 - Target repository (from `target-repo` or current repo) is always implicitly allowed
 - Creates a union of allowed destinations
 
+### Checkout Requirement for `push-to-pull-request-branch`
+
+Unlike other safe output types, `push-to-pull-request-branch` with `target-repo` requires the target repository to be **checked out into the workflow workspace** using the `checkout:` frontmatter field with a `path:` specified. Without a checkout, the agent has no local git history to create and push a patch from.
+
+See the [Scheduled Push to Pull-Request Branch](#example-scheduled-push-to-pull-request-branch) example and the [Push to PR Branch cross-repo usage](/gh-aw/reference/safe-outputs-pull-requests/#cross-repo-usage) documentation for a complete setup.
+
 ## Examples
 
 ### Example: Monorepo Development

docs/src/content/docs/reference/safe-outputs-pull-requests.md

@@ -264,10 +264,35 @@ safe-outputs:
     ignore-missing-branch-failure: false  # treat deleted/missing branch errors as skipped instead of failed (default: false)
     check-branch-protection: true         # set to false to skip the branch protection pre-flight check (default: true)
     protected-files: fallback-to-issue  # create review issue if protected files modified
+    target-repo: "owner/repo"    # cross-repository (target repo must be checked out)
+    allowed-repos: ["org/repo1"] # additional allowed repositories
 ```
 
 When `push-to-pull-request-branch` is configured, git commands (`checkout`, `branch`, `switch`, `add`, `rm`, `commit`, `merge`) are automatically enabled.
 
+### Cross-repo usage
+
+`push-to-pull-request-branch` supports pushing to pull requests in a different repository via `target-repo` (and optionally `allowed-repos`). When `target-repo` is set, **the target repository must be checked out into the workflow workspace** using the `checkout:` frontmatter field with a `path:` specified.
+
+```yaml wrap
+checkout:
+  - fetch-depth: 0                           # checkout current (source) repo
+  - repository: org/target-repo
+    path: ./target-repo                      # must set path for cross-repo checkout
+    github-token: ${{ secrets.CROSS_REPO_PAT }}
+    fetch: ["refs/pulls/open/*"]             # fetch all open PR branches
+
+safe-outputs:
+  github-token: ${{ secrets.CROSS_REPO_PAT }}
+  push-to-pull-request-branch:
+    target-repo: "org/target-repo"
+    title-prefix: "[bot] "
+```
+
+The `path:` field is required so the agent knows where the target repository is mounted in the workspace. Without a `path`, the checkout action writes to the root of the workspace and overwrites the source repository, which will cause the workflow to fail.
+
+See [Cross-Repository Operations](/gh-aw/reference/cross-repository/) for a complete example and documentation on `target-repo`, `allowed-repos`, and cross-repository authentication.
+
 Like `create-pull-request`, pushes with GitHub Agentic Workflows do not trigger CI. See [Triggering CI](/gh-aw/reference/triggering-ci/) for how to enable automatic CI triggers.
 
 ## Add Reviewer (`add-reviewer:`)

docs/src/content/docs/reference/safe-outputs.md

@@ -39,7 +39,7 @@ The agent requests issue creation; a separate job with `issues: write` creates i
 - [**Reply to PR Review Comment**](/gh-aw/reference/safe-outputs-pull-requests/#reply-to-pr-review-comment-reply-to-pull-request-review-comment) (`reply-to-pull-request-review-comment`) - Reply to existing review comments (max: 10)
 - [**Resolve PR Review Thread**](/gh-aw/reference/safe-outputs-pull-requests/#resolve-pr-review-thread-resolve-pull-request-review-thread) (`resolve-pull-request-review-thread`) - Resolve review threads after addressing feedback (max: 10)
 - [**Add Reviewer**](/gh-aw/reference/safe-outputs-pull-requests/#add-reviewer-add-reviewer) (`add-reviewer`) - Add reviewers to pull requests (max: 3)
-- [**Push to PR Branch**](/gh-aw/reference/safe-outputs-pull-requests/#push-to-pr-branch-push-to-pull-request-branch) (`push-to-pull-request-branch`) - Push changes to PR branch (default max: 1, configurable, same-repo only)
+- [**Push to PR Branch**](/gh-aw/reference/safe-outputs-pull-requests/#push-to-pr-branch-push-to-pull-request-branch) (`push-to-pull-request-branch`) - Push changes to PR branch (default max: 1, configurable; cross-repo supported via `target-repo` when the target repository is checked out)
 
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