osgrep

osgrep is a skill for Claude Code, Codex from pr-pm/prpm. It costs 56 tokens per session (679 once invoked), scanned A, original, MIT.

A tool for finding code by describing its purpose in everyday language instead of matching exact words.

In plain words
What is it for?
Use it to find authentication checks, plugin loading, API behavior, file-watching code, and other implementation details across a codebase.
Why use it?
It helps locate unfamiliar logic when you do not know which files or function names contain it.

Skill for Claude CodeCodex

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/pr-pm/prpm/osgrep-skill
Any agent
npx skills add pr-pm/prpm --skill osgrep-skill
Clone the repo
git clone --depth 1 https://github.com/pr-pm/prpm

Made for: Claude Code, Codex.

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 osgrep

README.md
[![agentmods](https://agentmods.dev/badge/skills/pr-pm/prpm/osgrep-skill.svg)](https://agentmods.dev/skills/pr-pm/prpm/osgrep-skill)
Your own site
<a href="https://agentmods.dev/skills/pr-pm/prpm/osgrep-skill"><img src="https://agentmods.dev/badge/skills/pr-pm/prpm/osgrep-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 679 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 $0.00056 $0.00679
Opus 5 $0.00028 $0.00340
Sonnet 5 $0.00011 $0.00136
Haiku 4.5 $0.00006 $0.00068

Measured 4d ago against content hash 09edd4627d5c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

osgrep 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 4d 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.

.claude/skills/osgrep-skill/SKILL.md · 54 lines

What it actually says

When to Use

Use this to find code by concept or behavior (e.g., "where is auth validated", "how are plugins loaded"). Note: This tool prioritizes finding the right files and locations in the code. Snippets are truncated (max 16 lines) and are often just previews.

Example:

osgrep "how are plugins loaded"
osgrep "how are plugins loaded" packages/transformers.js/src

Strategy for Different Query Types

For Architectural/System-Level Questions (auth, LSP integration, file watching)

  1. Search Broadly First: Use a conceptual query to map the landscape.
    • osgrep "authentication authorization checks"
  2. Survey the Results: Look for patterns across multiple files:
    • Are checks in middleware? Decorators? Multiple services?
    • Do file paths suggest different layers (gateway, handlers, utils)?
  3. Read Strategically: Pick 2-4 files that represent different aspects:
    • Read the main entry point
    • Read representative middleware/util files
    • Follow imports if architecture is unclear
  4. Refine with Specific Searches: If one aspect is unclear:
    • osgrep "session validation logic"
    • osgrep "API authentication middleware"

For Targeted Implementation Details (specific function, algorithm)

  1. Search Specifically: Ask about the precise logic.
    • osgrep "logic for merging user and default configuration"
  2. Evaluate the Semantic Match:
    • Does the snippet look relevant?
    • Crucial: If it ends in ... or cuts off mid-logic, read the file.
  3. One Search, One Read: Use osgrep to pinpoint the best file, then read it fully.

Output Format

Returns: path/to/file:line [Tags] Code Snippet

  • [Definition]: Semantic search detected a class/function here. High relevance.
  • ...: Truncation Marker. Snippet is incomplete—use read_file for full context.

Tips

  • Trust the Semantics: You don't need exact names. osgrep "how does the server start" works better than guessing osgrep "server.init".
  • Watch for Distributed Patterns: If results span 5+ files in different directories, the feature is likely architectural—survey before diving deep.
  • Scope When Possible: Use path constraints to focus: osgrep "auth" src/server/
  • Don't Over-Rely on Snippets: For architectural questions, snippets are signposts, not answers. Read the key files.
  • "Still Indexing...": If you see this, please stop, alert the user that the index is ongoing and ask them if they wish to proceed. Results will be partial until the index is complete.
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. 4d ago First seen · 54 lines · 56 tokens per session scan A 09edd4627d5c

Subscribe to this mod's changes

osgrep is a skill published in the GitHub repository pr-pm/prpm (120 stars, last pushed 2mo ago), licensed MIT. It adds 56 tokens to every session and 679 once invoked, about $0.0003 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.