---
name: Gather Context
description: 'Determine what to review, construct the diff, and load any spec/context documents.'
diff_output: '' # set at runtime
spec_file: '' # set at runtime (path or empty)
review_mode: '' # set at runtime: "full" or "no-spec"
---

# Step 1: Gather Context

## RULES

- YOU MUST ALWAYS SPEAK OUTPUT in your Agent communication style with the config `{communication_language}`
- Do not modify any files. This step is read-only.

## INSTRUCTIONS

1. Ask the user: **What do you want to review?** Present these options:
   - **Uncommitted changes** (staged + unstaged)
   - **Staged changes only**
   - **Branch diff** vs a base branch (ask which base branch)
   - **Specific commit range** (ask for the range)
   - **Provided diff or file list** (user pastes or provides a path)

2. Construct `{diff_output}` from the chosen source.
   - For **branch diff**: verify the base branch exists before running `git diff`. If it does not exist, HALT and ask the user for a valid branch.
   - For **commit range**: verify the range resolves. If it does not, HALT and ask the user for a valid range.
   - For **provided diff**: validate the content is non-empty and parseable as a unified diff. If it is not parseable, HALT and ask the user to provide a valid diff.
   - For **file list**: validate each path exists in the working tree. Construct `{diff_output}` by running `git diff HEAD -- <path1> <path2> ...`. If the diff is empty (files have no uncommitted changes), ask the user whether to review the full file contents or to specify a different baseline.
   - After constructing `{diff_output}`, verify it is non-empty regardless of source type. If empty, HALT and tell the user there is nothing to review.

3. Ask the user: **Is there a spec or story file that provides context for these changes?**
   - If yes: set `{spec_file}` to the path provided, verify the file exists and is readable, then set `{review_mode}` = `"full"`.
   - If no: set `{review_mode}` = `"no-spec"`.

4. If `{review_mode}` = `"full"` and the file at `{spec_file}` has a `context` field in its frontmatter listing additional docs, load each referenced document. Warn the user about any docs that cannot be found.

5. Sanity check: if `{diff_output}` exceeds approximately 3000 lines, warn the user and offer to chunk the review by file group.
   - If the user opts to chunk: agree on the first group, narrow `{diff_output}` accordingly, and list the remaining groups for the user to note for follow-up runs.
   - If the user declines: proceed as-is with the full diff.

### CHECKPOINT

Present a summary before proceeding: diff stats (files changed, lines added/removed), `{review_mode}`, and loaded spec/context docs (if any). HALT and wait for user confirmation to proceed.


## NEXT

Read fully and follow `./step-02-review.md`