Imported from trailofbits/skills (
plugins/trailmark/skills/trailmark-variant-neighborhood/SKILL.md) via skills.sh. Install upstream withnpx skills add trailofbits/skills --skill trailmark-variant-neighborhood. Copyright stays with the author.
Trailmark Variant Neighborhood
Expand one seed issue into graph-derived variant candidates. This skill generates review targets, not confirmed findings.
When to Use
- A finding is confirmed or plausible and variants may exist
- The vulnerable pattern depends on call context
- The issue involves a shared sink, source, validator, interface, override, trait, hook, handler, adapter, or critical type
- The next step is to seed
variant-analysis,semgrep-rule-creator,static-analysis, or manual review
When NOT to Use
- No seed issue exists. Use discovery or triage first.
- The pattern is purely syntactic and already obvious. Use
semgrep-rule-creatordirectly. - The question is exploit-chain composition across multiple findings. Use a composition workflow.
- The goal is remediation verification. Use a remediation-review workflow.
- The seed cannot be bound to a graph node.
Rationalizations to Reject
| Rationalization | Why It Is Wrong | Required Action |
|---|---|---|
| "Nearby code means variant" | Proximity is only a candidate reason | Rank it as a review target |
| "Only exact same names matter" | Variants often share sinks or preconditions, not names | Expand across callers, callees, interfaces, and types |
| "Every candidate is a finding" | This skill outputs candidates for review | Avoid vulnerability claims |
| "Unreachable candidates can be ignored completely" | They may become reachable after refactors | Rank lower or list as deferred |
| "Graph candidates replace semantic pattern work" | Graph structure finds locations, not root-cause semantics | Hand off to variant-analysis, Semgrep, CodeQL, or manual review |
Workflow
Variant Neighborhood Progress:
- [ ] Step 1: Normalize and bind the seed
- [ ] Step 2: Expand graph neighborhoods
- [ ] Step 3: Rank candidates
- [ ] Step 4: Extract variant pattern guidance
- [ ] Step 5: Emit handoff packet
Step 1: Normalize And Bind The Seed
Accept finding text, file/line, function name, or output from
trailmark-finding-triage. Bind the seed to a Trailmark node and record the
root cause in plain language.
If the seed has no concrete graph binding, stop before inventing variants.
Step 2: Expand Neighborhoods
Use the dimensions in references/neighborhood-patterns.md:
- shared callers
- shared callees and sinks
- entrypoint path neighbors
- interface, override, trait, and implementation siblings
- file or module cluster neighbors
- taint or privilege-boundary peers
- type and state-reference neighbors
Bound expansion to avoid candidate floods.
Step 3: Rank Candidates
Rank with references/ranking.md. Prioritize entrypoint-reachable, tainted, boundary-adjacent, high-blast-radius, shared sink, same-interface, and close-distance candidates. Penalize test, mock, generated, vendor, unreachable, and trusted-internal-only candidates.
Step 4: Extract Pattern Guidance
Summarize what should be searched for syntactically and what requires semantic review. Identify whether follow-up belongs in:
variant-analysissemgrep-rule-creatorstatic-analysiswith CodeQL or SARIF-producing tools- manual review
Step 5: Emit Handoff Packet
Use references/output-format.md. Include ranked candidates, inclusion reasons, exclusions, limitations, and the variant-analysis handoff.
Stop Conditions
- No graph binding exists
- Candidate count is too high and the root cause is underspecified
- Trailmark cannot analyze the target language
- The seed is only in test, generated, or vendor code and the user did not say that code is in scope