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.
npx skills add xdg/xdg-claude --skill ast-grepgit clone --depth 1 https://github.com/xdg/xdg-claudeWrote 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.
[](https://agentmods.dev/skills/xdg/xdg-claude/ast-grep)<a href="https://agentmods.dev/skills/xdg/xdg-claude/ast-grep"><img src="https://agentmods.dev/badge/skills/xdg/xdg-claude/ast-grep/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.
<a href="https://agentmods.dev/skills/xdg/xdg-claude/ast-grep"><img src="https://agentmods.dev/badge/skills/xdg/xdg-claude/ast-grep.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00044 | $0.00407 |
| Opus 5 | $0.00022 | $0.00204 |
| Sonnet 5 | $0.00009 | $0.00081 |
| Haiku 4.5 | $0.00004 | $0.00041 |
Grade A, and why
ast-grep 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 10d 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.
What it actually says
ast-grep
Default invocation:
ast-grep -l LANG -p 'PATTERN' # search
ast-grep -l LANG -p 'OLD' -r 'NEW' # preview rewrite
ast-grep -l LANG -p 'OLD' -r 'NEW' --update-all # apply
-l is required -- auto-detect is unreliable. Interactive mode (-i) does not work from this harness.
Metavariables
$VAR-- one AST node (an expression, an identifier, ...)$$$ARGS-- zero or more items in a list (function args, statement bodies)$$STMT-- multiple statements
Canonical patterns
# Rename a function across all call sites
ast-grep -l typescript -p 'oldFn($$$ARGS)' -r 'newFn($$$ARGS)'
# Rename a method on any receiver
ast-grep -l javascript -p '$OBJ.oldMethod($$$ARGS)' -r '$OBJ.newMethod($$$ARGS)'
# Rewrite imports
ast-grep -l typescript -p 'import $WHAT from "old-pkg"' -r 'import $WHAT from "new-pkg"'
Workflow: run without -r to see matches, run with -r to preview the diff, then add --update-all. For surgical per-site control, use ast-grep to find locations and Edit to apply.
To list a file's or package's structure (functions, types, imports/exports) rather than match a pattern, use the outline subcommand -- see the code-structure skill.
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.
- 10d ago First seen · 40 lines · 44 tokens per session scan A 61bf7cb2b608
ast-grep is a skill published in the GitHub repository xdg/xdg-claude (20 stars, last pushed 3d ago), licensed Apache-2.0. It adds 44 tokens to every session and 407 once invoked, about $0.0002 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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