Generates Mermaid diagrams from Trailmark code graphs. Produces call graphs, class hierarchies, module dependency maps, containment diagrams, complexity heatmaps, and attack surface data flow visualizations.
SkillScore36Maintained
Automatic
◆Coding pack
Last verified 8/7/2026
What it changes
Passed 3 of 9 test cases with the skill, and 2 of 9 without it.
Without skill23%
With skill36%
Checks it passed that the model alone missed
Invokes `uv run trailmark diagram`
Specifies `--language python,rust`
Executes or specifies `uv pip install trailmark`
and 4 more in the full report
7 fixed1 passed either way10 still failing4 broke
Pass-rate lift
+14 pp
Tokens
+31%
Agent turns
0%
Response time
-60%
Model gemini-3.6-flashMeasured 8/7/2026v18 of 22 cases passed with skill · 9 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 7
Prompt
We are running Trailmark version 0.4.1 where `trailmark diagram --help` succeeds. What command generates a call graph for `./src` focused on `init`?
What was checked, without and with the skill
Checked
Without skill
With skill
Invokes `uv run trailmark diagram`
Missed
Passed
case-15 · gemini-3.6-flash · 8/7/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md200 lines5 filesincludes scripts
Diagramming Code
Generates Mermaid diagrams from Trailmark's code graph. A pre-made script
handles Mermaid syntax generation; Claude selects the diagram type and
parameters. Trailmark 0.4.0 includes a native trailmark diagram command; use
it only after a version/command check, otherwise use this skill's bundled
script.
When to Use
Visualizing call paths between functions
Drawing class inheritance hierarchies
Mapping module import dependencies
Showing class structure with members
Highlighting complexity hotspots with color coding
Tracing data flow from entrypoints to sensitive functions
When NOT to Use
Querying the graph without visualization (use the trailmark skill)
Mutation testing triage (use the genotoxic skill)
Architecture diagrams not derived from code (draw by hand)
Prerequisites
trailmark must be installed. If uv run trailmark fails, run:
uv pip install trailmark
DO NOT fall back to hand-writing Mermaid from source code reading. The
script uses Trailmark's parsed graph for accuracy. If installation fails,
report the error to the user.