Trailmark Structural
Trail of BitsOfficialPublished by Trail of Bits
- Skill
- Research and analysis
- Security
- CC-BY-SA-4.0
- Low risk
AutoGineer summary
Written by AutoGineer from the skill’s own files, not by the author
The trailmark-structural skill executes a deep-dive analysis of a target codebase by building a graph and running the full suite of Trailmark pre-analysis passes. It is designed to provide security auditors and developers with detailed insights into taint paths, blast radius, privilege boundaries, and attack surfaces. The skill is version-aware, automatically adapting to Trailmark 0.4+ and 0.5+ features such as proxy node detection and enriched attack surface attributes, ensuring consistent data extraction across different environment configurations.
What it does
- Builds a comprehensive Trailmark graph for a specified target directory.
- Executes all four pre-analysis passes to identify security-relevant code patterns.
- Extracts complexity hotspots, taint analysis results, and privilege boundary data.
- Identifies proxy nodes and subgraph edges to map unresolved calls and external links.
- Generates type-reference summaries and entrypoint attributes for deeper architectural inspection.
- Provides a structured JSON payload containing the complete analysis output for audit prioritization.
When to use it
- When performing Phase 1 vivisect analysis requiring full structural data.
- When you need to identify complexity hotspots and taint paths for audit prioritization.
- When investigating privilege boundaries and attack surfaces in a complex codebase.
- When you need to inspect proxy counts or subgraph edges using Trailmark 0.4.0+.
Advantages
- Automates complex multi-pass analysis that would be error-prone if performed manually.
- Provides version-agnostic execution by probing for feature availability.
- Delivers granular data on blast radius and taint that summary tools omit.
- Standardizes the output format for downstream security analysis tools.
Usage examples
- “Run a full structural analysis on the project in ./src to identify potential attack surfaces.”
- The agent executes the Trailmark QueryEngine, performs pre-analysis, and returns a JSON report detailing the attack surface, complexity hotspots, and proxy nodes found in the source code.
- “Analyze the structural complexity and taint paths for the target directory /app/backend.”
- The agent generates a comprehensive report including taint analysis, privilege boundaries, and subgraph summaries to assist in identifying high-risk code areas.
Install
Download the skill as a ZIP:
https://mp-staging.autogineer.com/agent-skills/trailofbits/trailmark-structural/downloadUnzip it into the cross-client skills folder of your project:
mkdir -p .agents/skills && unzip trailmark-structural.zip -d .agents/skills
Documentation by Trail of Bits
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/nullIf 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 || trueDo 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])))
PYIf 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))
PYStep 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.
Files
- ATTRIBUTION.mdAdded by AutoGineer943 B
- LICENSELicence file added by AutoGineer19.7 KiB
- SKILL.md6.0 KiB
- agents/openai.yaml256 B
- assets/trail-of-bits-mark.svg3.0 KiB
Requirements and compatibility
Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta
“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.
Needs: Declares allowed tools, Needs Python, Needs Node.js
Security
What our scanner noticed· Low risk
- Instructions that use the network
A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.
Attribution and licence
- Published by
- Trail of Bits
- Publisher
- Trail of Bits (Official)
- Source
- trailofbits/skills · plugins/trailmark/skills/trailmark-structural · commit e4dd0bb
- Licence
- Creative Commons Attribution-ShareAlike 4.0 International (redistribution allowed)
- LICENSE (added by AutoGineer from LICENSE)
- ATTRIBUTION.md (written by AutoGineer)
- Synced
AutoGineer is not affiliated with or endorsed by Trail of Bits.
Download ZIP
The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download trailmark-structural.zip