code-structure

A code-outline tool that lists the structure of a file or package, including functions, classes, methods, types, imports, and exports. A package is a reusable group of related code files.

In plain words
What is it for?
Use it to survey an API, find where symbols are defined, inspect imports, or list selected kinds of code members.
Why use it?
It gives you a map of unfamiliar or large code before you open specific sections, reducing unnecessary reading.

Skill for Claude CodeCodex

Part of the context-efficient-tools plugin — 5 skills shipped together

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.

agentmods
npx agentmods add skills/xdg/xdg-claude/code-structure
Any agent
npx skills add xdg/xdg-claude --skill code-structure
Clone the repo
git clone --depth 1 https://github.com/xdg/xdg-claude

Made for: Claude Code, Codex.

Or install context-efficient-tools, the plugin that ships this one along with the rest of its 5 skills.

Per session 102 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 619 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00102 $0.00619
Opus 5 $0.00051 $0.00309
Sonnet 5 $0.00020 $0.00124
Haiku 4.5 $0.00010 $0.00062

Measured 3d ago against content hash 1d5e36ad71ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-structure 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 3d ago.

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.

context-efficient-tools/skills/code-structure/SKILL.md · 39 lines

What it actually says

code-structure

When the question is "list the X in Y", do not Read the whole file. Get an outline first; Read selectively after.

Trigger discrimination

  • "list / show / all the methods/classes/exports in ..." -- outline (this skill)
  • "where is X defined" / "find calls to X" -- search (rg or ast-grep)
  • "how does X work" / "what does X do" -- Read

Tiered approach

  1. ast-grep outline -- the default. One interface across languages, no build or import step, and every text view carries line numbers so you can Read just the range you need afterward. Pass -l to be safe (required for stdin; inferred from extension for paths).

    • File outline: ast-grep outline -l go file.go (digest: signatures + member names)
    • Cheapest survey: ast-grep outline -l go file.go --view names
    • Drill one symbol's members: ast-grep outline -l go file.go --match Visitor --view expanded
    • Directory's exported surface: ast-grep outline -l go ./pkg
    • Filter by kind: --type struct,function; by name: --match REGEX; public members only: --pub-members
    • Dependency check: ast-grep outline -l go file.go --items imports
    • Machine-readable: --json=compact (also pretty, stream)
  2. Compiler/parser-aware tool when you need true export semantics or docstrings, which outline does not carry:

    • Go: go doc -all ./path/to/pkg
    • Python: python -m pydoc some.module.path (requires the module to be importable -- deps installed, on PYTHONPATH)
    • TS/JS third-party: cat node_modules/<pkg>/dist/index.d.ts -- the declaration file is a pre-made API outline
    • Java: javap -p <Class> (requires compiled .class files)
  3. ctags fallback -- for languages outline's bundled rules don't cover; canonical for C/C++:

    ctags -f - file | grep -v '^!' | cut -f1,4    # symbol + kind
    

Use the outline to decide what to Read, then Read just that section.

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. 3d ago First seen · 39 lines · 102 tokens per session scan A 1d5e36ad71ec

Subscribe to this mod's changes

code-structure is a skill published in the GitHub repository xdg/xdg-claude (20 stars, last pushed 13d ago), licensed Apache-2.0. It adds 102 tokens to every session and 619 once invoked, about $0.0005 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 2026-08-30.

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