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Trailmark Structural

Trail of BitsOfficialPublished by Trail of Bits

  • Skill
  • Research and analysis
  • Security
  • CC-BY-SA-4.0
  • Low risk

From the author

Runs full Trailmark structural analysis by building a graph, running `preanalysis()`, and reporting hotspots, taint, blast radius, privilege boundaries, attack surface, and version-gated Trailmark 0.4+/0.5+ data such as proxy counts, subgraph edges, type/reference summaries, and entrypoint attributes. Use when vivisect needs detailed structural data for a target. Triggers: structural analysis, blast radius, taint analysis, complexity hotspots, proxy nodes, type references.
— the description by Trail of Bits

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

  1. Download the skill as a ZIP:

    https://autogineer.com/agent-skills/trailofbits/trailmark-structural/download
  2. Unzip 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-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.

Files

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 or Trail of Bits.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download trailmark-structural.zip