Trailmark Review Gate

Apply deterministic security gate rules to Trailmark structural diff evidence. This skill does not replace line-level review. It produces a compact structural packet reviewers can cite while they inspect the code.

When to Use

• Reviewing a branch, pull request, release diff, or fix commit
• Checking whether a change expands attack surface
• Looking for removed validation or authorization on reachable paths
• Comparing before/after taint, privilege-boundary, blast-radius, or complexity signals
• Producing graph evidence for a differential review

When NOT to Use

• Single-snapshot analysis. Use trailmark or trailmark-structural.
• Text-diff review only. Use differential-review.
• Full vulnerability discovery. Use an audit or bug-finding workflow.
• One static finding. Use trailmark-finding-triage.
• Tooling is unavailable and the user wants manual review only.

Rationalizations to Reject

Rationalization	Why It Is Wrong	Required Action
"The line diff is small, so no graph gate is needed"	Small changes can create new call paths	Compare before/after graphs
"Graph gate passed, so the PR is secure"	The gate only checks structural regressions	Still perform line-level review
"Trailmark failed, so pass the gate"	Tool failure is unknown risk, not success	Emit UNKNOWN
"Tests pass, so removed validation is fine"	Tests may miss affected entrypoint paths	Review the removed path manually
"Only new code matters"	Removed auth, validation, and callers can be higher risk than additions	Review removals and path changes

Workflow

Review Gate Progress:
- [ ] Step 1: Resolve before/after inputs
- [ ] Step 2: Build graph-evolution evidence
- [ ] Step 3: Normalize structural changes
- [ ] Step 4: Apply gate rules
- [ ] Step 5: Emit review packet and actions

Step 1: Resolve Inputs

Accept two refs, a branch name, a commit range, or before/after directories. Do not check out branches unnecessarily. Prefer git diff, git show, and git worktrees, following the graph-evolution snapshot workflow.

Step 2: Build Graph Evidence

Run graph-evolution or equivalent Trailmark before/after graph analysis. Both snapshots must run engine.preanalysis() so taint, privilege-boundary, blast-radius, complexity, and entrypoint signals are available.

Record Trailmark version and any feature probes. If graph construction fails, emit UNKNOWN.

Step 3: Normalize Changes

Normalize evidence into:

• added, removed, and modified nodes
• added and removed edges
• entrypoint set changes
• taint membership changes
• privilege-boundary membership changes
• blast-radius changes
• complexity changes
• newly reachable sensitive sinks
• unresolved, proxy, or dynamic edge changes

Step 4: Apply Gate Rules

Apply the rules in references/gate-rules.md. Gate verdicts are:

Verdict	Meaning
FAIL	A high-risk structural regression needs review before acceptance
WARN	A meaningful graph change needs reviewer attention
PASS	No configured structural gate fired
UNKNOWN	Trailmark failed or evidence is too incomplete

Step 5: Emit Packet

Write the packet using references/output-format.md, then hand it to the branch reviewer. Use references/review-integration.md when combining this packet with differential-review or another PR review process.

Requirements

• Never mutate the user's working branch while comparing refs.
• Never report PASS when Trailmark failed.
• Separate graph evidence from manual security judgment.
• Include exact changed nodes or paths for every FAIL and WARN.
• Include limitations when parser, proxy, unresolved-call, or dynamic-dispatch uncertainty affects the verdict.