Trailmark Structural Agent Skill

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

| 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 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 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.