SKILL·8283CB

trailmark-structural

trailofbits
Updated 15 days ago
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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

Recommended
Primary
npx skills add trailofbits/skills -a claude-code
Plugin CommandAlternative
/plugin add https://github.com/trailofbits/skills
Git CloneAlternative
git clone https://github.com/trailofbits/skills.git ~/.claude/skills/trailmark-structural

Copy 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-summary instead)
  • Ad-hoc code graph queries (use the main trailmark skill directly)
  • Target is a single small file where structural analysis adds no value

Rationalizations to Reject

RationalizationWhy It's WrongRequired Action
"Summary analysis is enough"Summary skips taint, blast radius, and privilege boundary dataRun full structural analysis when detailed data is needed
"One pass is sufficient"Passes cross-reference each other — taint without blast radius misses critical nodesRun all four passes
"Tool isn't installed, I'll analyze manually"Manual analysis misses what tooling catchesReport "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 installedProbe 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:

  • languages
  • summary
  • preanalysis
  • hotspots (possibly empty)
  • proxy_nodes (empty on v0.2.x or when there are no unresolved calls; on 0.5.0+ may include proxy.external:* entries declared in .trailmark/links.toml)
  • subgraphs with 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

trailofbits/skills
Path: plugins/trailmark/skills/trailmark-structural
0
agent-skills
FAQ

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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