corvus-review-r0

name: corvus-review-r0 description: PR Review Phase R0 - Intake, triage, PR metadata fetching, config loading

Phase R0: INTAKE & TRIAGE

Goal: Parse PR reference, fetch metadata, load config, run triage checks.

Executor: Corvus-Review direct (no subagent delegation).

Input: User-provided PR reference (URL, #number, or owner/repo#number).

Output: PR_CONTEXT object (see corvus-review-extras for schema).

STEP 0: PARSE PR REFERENCE

Extract the PR identifier from the user's input. Supported formats:

If no PR reference is provided:

## PR Reference Required

Please provide a PR to review. Supported formats:
- `#123` (current repo)
- `owner/repo#123`
- `https://github.com/owner/repo/pull/123`
- Or just the number: `123`

Validation: After parsing, verify the PR exists:

gh pr view <number> --repo <owner/repo> --json number,title --jq '.number' 2>&1

If this fails, abort with a clear error (see corvus-review-extras error handling).

STEP 1: FETCH PR METADATA

Run the following gh commands to populate PR_CONTEXT fields:

1a. Core Metadata

gh pr view <number> --repo <owner/repo> --json \
  number,url,title,body,author,baseRefName,headRefName,\
  labels,reviewRequests,isDraft,mergeable,\
  additions,deletions,changedFiles,files

Field Mapping:

• pr_number ← number
• pr_url ← url
• title ← title
• description ← body (set to null if empty string or missing)
• author ← author.login
• base_branch ← baseRefName
• head_branch ← headRefName
• labels ← labels[].name
• reviewers_requested ← reviewRequests[].login
• is_draft ← isDraft
• mergeable ← mergeable (map: "MERGEABLE" → true, "CONFLICTING" → false, else → null)
• additions ← additions
• deletions ← deletions
• files_changed ← changedFiles
• changed_files ← files[].path

1b. CI Status

gh pr checks <number> --repo <owner/repo> --json name,state,detailsUrl 2>&1

Field Mapping:

• For each check: { name, status: state_to_status(state), url: detailsUrl }
• state_to_status: "SUCCESS" / "NEUTRAL" / "SKIPPED" → "pass", "FAILURE" / "ERROR" → "fail", "PENDING" / "QUEUED" / "IN_PROGRESS" → "pending"
• ci_status (aggregate): if any "fail" → "fail", else if any "pending" → "pending", else if all "pass" → "pass", else "none" (no checks)

1c. Linked Issues

Parse linked issues from:

1. PR body: scan for fixes #N, closes #N, resolves #N (case-insensitive)
2. PR metadata: gh pr view --json closingIssuesReferences

Deduplicate and store as linked_issues: ["#N", "#M"].

1d. Repo Identification

gh repo view --json nameWithOwner --jq '.nameWithOwner'

Store as repo.

STEP 2: LOAD REVIEW CONFIG

2a. Attempt Config Load

cat .opencode/review-config.yaml 2>/dev/null

2b. Parse and Validate

If the file exists:

1. Parse YAML
2. Validate each field against the schema (see corvus-review-extras)
3. For invalid fields: log a warning, use the default for that field
4. For unknown keys: log a warning, ignore
5. Merge with defaults for any missing fields

If the file does not exist:

• Use all defaults (see corvus-review-extras for default values)
• This is normal and expected — config is optional

If the file has a YAML parse error:

• Log the error with line number
• Fall back to all defaults
• Set a flag: config_parse_error: true (included in review summary later)

2c. Apply Config

Store the validated config as PR_CONTEXT.config.

STEP 3: TRIAGE

Evaluate the PR against triage checks and set flags in PR_CONTEXT.flags:

3a. Draft Check

flags.is_draft = PR_CONTEXT.is_draft

If draft:

## Draft PR Detected

PR #[number] is marked as draft. Proceeding with review, but findings
will be posted as COMMENT_ONLY (not REQUEST_CHANGES) regardless of severity.

Set config.action_override = "COMMENT_ONLY" if draft and no explicit override exists.

3b. Large PR Check

flags.is_large_pr = (PR_CONTEXT.files_changed > config.large_pr_threshold)

If large PR, apply config.large_pr_strategy:

For "warn" and "split-suggestion", display:

## Large PR Warning

This PR changes **[N] files** (threshold: [T]).
[If split-suggestion: Consider splitting this into smaller, focused PRs for easier review.]
Proceeding with review.

3c. Missing Description Check

flags.missing_description = (PR_CONTEXT.description == null or PR_CONTEXT.description.trim() == "")

If missing:

• Add a note finding to be included in the review: "PR has no description. Consider adding context for reviewers."
• Do NOT abort — this is a finding, not a blocker.

3d. CI Failure Check

flags.has_ci_failures = (PR_CONTEXT.ci_status == "fail")

If CI is failing:

• Note in context for R1's @researcher to analyze
• Do NOT abort — CI failures are analyzed and reported as part of the review

3e. Breaking Label Check

flags.has_breaking_labels = labels.any(l => 
  ["breaking-change", "breaking", "semver-major"].includes(l.toLowerCase())
)

If breaking labels found:

• Note for R2 passes: "PR has breaking-change label. Evaluate backward compatibility."

STEP 4: PRODUCE PR_CONTEXT

Assemble the complete PR_CONTEXT object from all gathered data.

Output Format

Present a summary to the user:

## PR Review: #[number] — [title]

| Field | Value |
|-------|-------|
| Author | @[author] |
| Branch | [head_branch] → [base_branch] |
| Changes | +[additions] / -[deletions] across [files_changed] files |
| CI | [ci_status_emoji] [ci_status] |
| Draft | [yes/no] |

### Triage Flags
[List any active flags with their implications]

### Config
- Severity threshold: [threshold]
- Max nits: [max_nits]
- Passes enabled: [list]
- Autonomous: [yes/no]

**Proceeding to context gathering (R1)...**

Status emojis for CI: pass = [PASS], fail = [FAIL], pending = [PENDING], none = [NONE]

GATE ENFORCEMENT