Default (no args): uncommitted + staged - Gastown

Review code and provide a structured assessment with grading.

Arguments: $ARGUMENTS

Diff Source Resolution

Determine the diff to review based on arguments:

Argument	Diff command	Use case
(none)	`git diff` + `git diff --staged`	Review uncommitted + staged changes
`--staged`	`git diff --staged`	Review only staged changes
`--branch`	`git diff origin/<base>...HEAD`	Review branch diff vs base branch
`--pr <url>`	`gh pr diff <url>`	Review a GitHub PR

Step 1: Get the diff

Based on the arguments, run the appropriate diff command:

bash

# Default (no args): uncommitted + staged
DIFF=$(git diff; git diff --staged)

# --staged: only staged
DIFF=$(git diff --staged)

# --branch: branch diff (detect base branch)
BASE=$(git rev-parse --abbrev-ref HEAD@{upstream} 2>/dev/null | sed 's|origin/||' || git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's|refs/remotes/origin/||' || echo "main")
DIFF=$(git diff origin/$BASE...HEAD)

# --pr <url>: PR diff
DIFF=$(gh pr diff <url>)

If the diff is empty, report "No changes to review" and stop.

Step 2: Review the diff

Review the diff systematically. For each issue found, classify by severity:

CRITICAL - Must fix before merge:

Security vulnerabilities (injection, auth bypass, secrets in code)
Data loss risks (missing transactions, unsafe deletes)
Correctness bugs (race conditions, nil dereference, logic errors)

MAJOR - Should fix before merge:

Logic errors that may not crash but produce wrong results
Missing error handling on external calls
API contract violations
Missing tests for critical paths

MINOR - Nice to fix:

Style inconsistencies with surrounding code
Naming issues (unclear or misleading names)
Missing comments on non-obvious logic
Minor code smells

For each issue, note:

File and line number
Severity (CRITICAL, MAJOR, MINOR)
Description of the issue
Suggested fix (specific, actionable)

Step 3: Assign grade

Grade is determined by the highest severity issue found:

Grade	Criteria	Verdict
A	No CRITICAL, MAJOR, or MINOR issues	PASS
B	MINOR issues only (no CRITICAL or MAJOR)	PASS
C	MAJOR issues present (no CRITICAL)	FAIL
D	CRITICAL issues present	FAIL
F	Unreviewable (empty diff, binary files, generated code only)	SKIP

Step 4: Output structured review

Output the review in this exact format:

Grade: <A|B|C|D|F>

CRITICAL (<count> issues)
  <file>:<line> — <description>
    Suggested fix: <actionable fix>

MAJOR (<count> issues)
  <file>:<line> — <description>
    Suggested fix: <actionable fix>

MINOR (<count> issues)
  <file>:<line> — <description>
    Suggested fix: <actionable fix>

Summary: <N> CRITICAL, <N> MAJOR, <N> MINOR
Verdict: <PASS|FAIL|SKIP>

Omit empty severity sections (e.g., if no CRITICAL issues, don't print the CRITICAL section).

If Grade is A, output:

Grade: A

No issues found.

Summary: 0 CRITICAL, 0 MAJOR, 0 MINOR
Verdict: PASS