trailmark-structural
About
This skill performs comprehensive Trailmark structural analysis by building a dependency graph and running preanalysis to identify security hotspots, taint flows, and attack surfaces. It provides version-aware reporting including proxy nodes, type references, and entrypoint attributes for detailed codebase assessment. Use it when you need deep structural insights about a target's architecture and security posture.
Quick Install
Claude Code
Recommendednpx skills add trailofbits/skills -a claude-code/plugin add https://github.com/trailofbits/skillsgit clone https://github.com/trailofbits/skills.git ~/.claude/skills/trailmark-structuralCopy and paste this command in Claude Code to install this skill
Documentation
Trailmark Structural Analysis
Builds a Trailmark graph and runs engine.preanalysis() to compute all
four pre-analysis passes. The core workflow is v0.2-safe; v0.4-only details
are included only after checking method availability, and newer builds
enrich the same output (0.5.0+ adds an attributes key to attack-surface
entries and proxy.external:* nodes from .trailmark/links.toml) without
any workflow change.
When to Use
- Vivisect Phase 1 needs full structural data (hotspots, taint, blast radius, privilege boundaries)
- Detailed pre-analysis passes for a specific target scope
- Generating complexity and taint data for audit prioritization
- Inspecting proxy/unresolved-call counts, subgraph edges, or type-reference summaries when Trailmark 0.4.0+ is installed
When NOT to Use
- Quick overview only (use
trailmark-summaryinstead) - Ad-hoc code graph queries (use the main
trailmarkskill directly) - Target is a single small file where structural analysis adds no value
Rationalizations to Reject
| Rationalization | Why It's Wrong | Required Action |
|---|---|---|
| "Summary analysis is enough" | Summary skips taint, blast radius, and privilege boundary data | Run full structural analysis when detailed data is needed |
| "One pass is sufficient" | Passes cross-reference each other — taint without blast radius misses critical nodes | Run all four passes |
| "Tool isn't installed, I'll analyze manually" | Manual analysis misses what tooling catches | Report "trailmark is not installed" and return |
| "Empty pass output means the pass failed" | Some passes produce no data for some codebases (e.g., no privilege boundaries) | Return full output regardless |
| "A v0.4 field is always present" | Users may still have Trailmark 0.2.x installed | Probe with hasattr() before querying v0.4-only methods |
Usage
The target directory is passed via the args parameter.
Execution
Step 1: Check that trailmark is available.
trailmark analyze --help 2>/dev/null || \
uv run trailmark analyze --help 2>/dev/null
If neither command works, report "trailmark is not installed"
and return. Do NOT run pip install, uv pip install,
git clone, or any install command. The user must install
trailmark themselves.
Optionally record the version:
trailmark --version 2>/dev/null || uv run trailmark --version 2>/dev/null || true
Do not fail if this command is missing; use API feature probes below.
Step 2: Detect languages with Trailmark's parse API.
python3 - "{args}" <<'PY'
import json
import sys
try:
from trailmark.parse import detect_languages # canonical location since 0.3.x
except ModuleNotFoundError:
# v0.2.x predates trailmark.parse; the same function lives in query.api
from trailmark.query.api import detect_languages
print(json.dumps(detect_languages(sys.argv[1])))
PY
If the import fails, rerun the same snippet with uv run --with trailmark python - "{args}".
If the result is [], report "Trailmark found no supported languages under
target" and return.
Step 3: Run the full structural analysis via QueryEngine.
Run this snippet with python3. If the import fails, rerun the same snippet
under uv run --with trailmark python - "{args}".
python3 - "{args}" <<'PY'
import json
import sys
try:
from trailmark.parse import detect_languages # canonical location since 0.3.x
except ModuleNotFoundError:
# v0.2.x predates trailmark.parse; the same function lives in query.api
from trailmark.query.api import detect_languages
from trailmark.query.api import QueryEngine
target = sys.argv[1]
languages = detect_languages(target)
engine = QueryEngine.from_directory(target, language="auto")
preanalysis = engine.preanalysis()
def summarize_subgraph(name: str, limit: int = 25) -> dict[str, object]:
nodes = engine.subgraph(name)
summary = {
"count": len(nodes),
"sample_ids": [node["id"] for node in nodes[:limit]],
}
if hasattr(engine, "subgraph_edges"):
summary["edge_count"] = len(engine.subgraph_edges(name))
return summary
graph = json.loads(engine.to_json())
nodes = graph.get("nodes", {})
proxy_nodes = [
node_id for node_id, node in nodes.items()
if node.get("kind") == "proxy" or node.get("origin") == "proxy"
]
payload = {
"languages": languages,
"summary": engine.summary(),
"preanalysis": preanalysis,
"attack_surface": engine.attack_surface()[:25],
"hotspots": engine.complexity_hotspots(10)[:25],
"proxy_nodes": proxy_nodes[:25],
"subgraphs": {
name: summarize_subgraph(name)
for name in engine.subgraph_names()
},
}
if hasattr(engine, "type_references"):
payload["type_reference_samples"] = {
node_id: engine.type_references(node_id)[:10]
for node_id in list(nodes)[:25]
}
print(json.dumps(payload, indent=2))
PY
Step 4: Verify the output.
The output should include:
languagessummarypreanalysishotspots(possibly empty)proxy_nodes(empty on v0.2.x or when there are no unresolved calls; on 0.5.0+ may includeproxy.external:*entries declared in.trailmark/links.toml)subgraphswith counts and sample IDs
On Trailmark 0.5.0+, attack_surface entries may carry an attributes
object (e.g. solidity_visibility, solidity_overridden_by). Pass it
through unchanged — downstream consumers use it to rank entrypoints.
Some subgraphs may have zero nodes for some codebases (this is normal). Return the full JSON payload regardless.
GitHub Repository
Frequently asked questions
What is the trailmark-structural skill?
trailmark-structural is a Claude Skill by trailofbits. Skills package instructions and resources that Claude loads on demand, so Claude can perform trailmark-structural-related tasks without extra prompting.
How do I install trailmark-structural?
Use the install commands on this page: add trailmark-structural to Claude Code as a plugin, or clone its repository into your skills directory, then restart Claude so it picks up the skill.
What category does trailmark-structural belong to?
trailmark-structural is in the Meta category.
Is trailmark-structural free to use?
Yes. trailmark-structural is listed on AIMCP and free to install.
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