ascii-diagram-validator

ascii-diagram-validator is a skill for Claude Code from terrylica/cc-skills. It costs 28 tokens per session (1,617 once invoked), scanned A, original, MIT.

A checker for alignment problems in ASCII diagrams, which are drawings made from text characters. It checks box-drawing diagrams in Markdown, documentation, and code comments and reports the location of problems.

In plain words
What is it for?
Use it to validate architecture diagrams in individual files or directories before reviewing or committing documentation.
Why use it?
Misaligned text diagrams can be difficult to spot and may look broken in another font or viewer. The checker gives file, line, and column information plus correction suggestions.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions Claude Code.

Part of the doc-tools plugin — 13 skills shipped together , and of cc-skills

Good fit Use it to validate architecture diagrams in individual files or directories before reviewing or committing documentation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/terrylica/cc-skills/ascii-diagram-validator
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add terrylica/cc-skills --skill ascii-diagram-validator
Clone the repo
git clone --depth 1 https://github.com/terrylica/cc-skills

Made for: Claude Code.

Or install doc-tools, the plugin that ships this one along with the rest of its 13 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ascii-diagram-validator

README.md
[![agentmods](https://agentmods.dev/badge/skills/terrylica/cc-skills/ascii-diagram-validator/github.svg)](https://agentmods.dev/skills/terrylica/cc-skills/ascii-diagram-validator)
Your own site
<a href="https://agentmods.dev/skills/terrylica/cc-skills/ascii-diagram-validator"><img src="https://agentmods.dev/badge/skills/terrylica/cc-skills/ascii-diagram-validator/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ascii-diagram-validator

Your own site · 80×15
<a href="https://agentmods.dev/skills/terrylica/cc-skills/ascii-diagram-validator"><img src="https://agentmods.dev/badge/skills/terrylica/cc-skills/ascii-diagram-validator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,617 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Rogue Agent · line 182
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00028 $0.01617
Opus 5 $0.00014 $0.00809
Sonnet 5 $0.00006 $0.00323
Haiku 4.5 $0.00003 $0.00162

Measured 6d ago against content hash 062c9a361b3c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

ascii-diagram-validator scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/check_ascii_alignment.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/doc-tools/skills/ascii-diagram-validator/SKILL.md · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ASCII Diagram Validator

Validate and fix alignment issues in ASCII box-drawing diagrams commonly used in architecture documentation, README files, and code comments.

Self-Evolving Skill: This skill improves through use. If instructions are wrong, parameters drifted, or a workaround was needed — fix this file immediately, don't defer. Only update for real, reproducible issues.

Overview

ASCII diagrams using box-drawing characters (─│┌┐└┘├┤┬┴┼ and double-line variants ═║╔╗╚╝╠╣╦╩╬) require precise column alignment. This skill provides:

  1. Validation script - Detects misaligned characters with file:line:column locations
  2. Actionable fixes - Specific suggestions for correcting each issue
  3. Multi-file support - Validate individual files or entire directories

When to Use This Skill

Invoke when:

  • Creating or editing ASCII architecture diagrams in markdown
  • Reviewing documentation with box-drawing diagrams
  • Fixing "diagram looks wrong" complaints
  • Before committing docs/ARCHITECTURE.md or similar files
  • When user mentions "ASCII alignment", "diagram alignment", or "box drawing"

Supported Characters

Single-Line Box Drawing

Corners: ┌ ┐ └ ┘
Lines:   ─ │
T-joins: ├ ┤ ┬ ┴
Cross:   ┼

Double-Line Box Drawing

Corners: ╔ ╗ ╚ ╝
Lines:   ═ ║
T-joins: ╠ ╣ ╦ ╩
Cross:   ╬

Mixed (Double-Single)

╞ ╟ ╤ ╧ ╪ ╫

Quick Start

Validate a Single File

/usr/bin/env bash << 'PREFLIGHT_EOF'
uv run "$(cc-plugin-root doc-tools)/skills/ascii-diagram-validator/scripts/check_ascii_alignment.py" docs/ARCHITECTURE.md
PREFLIGHT_EOF

Validate Multiple Files

/usr/bin/env bash << 'PREFLIGHT_EOF_2'
uv run "$(cc-plugin-root doc-tools)/skills/ascii-diagram-validator/scripts/check_ascii_alignment.py" docs/*.md
PREFLIGHT_EOF_2

Validate Directory

/usr/bin/env bash << 'PREFLIGHT_EOF_3'
uv run "$(cc-plugin-root doc-tools)/skills/ascii-diagram-validator/scripts/check_ascii_alignment.py" docs/
PREFLIGHT_EOF_3

Read the full file on GitHub · 185 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 185 lines · 28 tokens per session scan A 062c9a361b3c

Subscribe to this mod's changes

ascii-diagram-validator is a skill published in the GitHub repository terrylica/cc-skills (72 stars, last pushed yesterday), licensed MIT. It adds 28 tokens to every session and 1,617 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-05.

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