Semantic code search tool that finds files and logic based on intent rather than exact keyword matches.

Install

mkdir -p .claude/skills/osgrep && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/220" && unzip -o skill.zip -d .claude/skills/osgrep && rm skill.zip

Installs to .claude/skills/osgrep

Activation

This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.

Semantic code search using natural language queries. Use when users ask "where is X implemented", "how does Y work", "find the logic for Z", or need to locate code by concept rather than exact text. Returns file paths with line numbers and code snippets.
254 chars✓ has a “when” triggerlonger than Claude Code's old 250-char listing cap (fine on current versions)
Beginner

Key capabilities

  • Perform semantic search across large codebases
  • Map conceptual questions to specific file paths
  • Retrieve relevant snippets with context tags
  • Navigate system architecture by logic behavior

How it works

Utilizes a background indexer to perform vector-based semantic matches rather than standard regex string searching.

Inputs & outputs

You give it
Natural language query about code functionality
You get back
File paths, line numbers, and truncated code snippets

When to use osgrep

  • Locate implementation of authentication logic
  • Understand how plugins are loaded in the system
  • Search for architectural patterns by concept
  • Find specific algorithm implementations

About this skill

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.

When not to use it

  • Simple text-based grepping for exact strings
  • Locating files by partial filenames

Limitations

  • Snippets are frequently truncated and require manual reading
  • Depends on index accuracy and background process status

How it compares

Allows searching by 'intent' or 'concept' instead of requiring exact variable/function names.

Compared to similar skills

osgrep side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
osgrep (this skill)136moReviewBeginner
mgrep467moReviewBeginner
tldr-router16moReviewBeginner
data-collection03moNo flagsBeginner

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