osgrep

name: osgrep description: Semantic code search. Use alongside grep - grep for exact strings, osgrep for concepts. allowed-tools: "Bash(osgrep:*), Read"

What osgrep does

Finds code by meaning. When you'd ask a colleague "where do we handle auth?", use osgrep.

• grep/ripgrep: exact string match, fast
• osgrep: concept match, finds code you couldn't grep for

Primary command

osgrep "where do we validate user permissions"

Returns ~10 results with code snippets (15+ lines each). Usually enough to understand what's happening.

Output explained

ORCHESTRATION src/auth/handler.ts:45
Defines: handleAuth | Calls: validate, checkRole, respond | Score: .94

export async function handleAuth(req: Request) {
  const token = req.headers.get("Authorization");
  const claims = await validateToken(token);
  if (!claims) return unauthorized();
  const allowed = await checkRole(claims.role, req.path);
  ...

• ORCHESTRATION = contains logic, coordinates other code
• DEFINITION = types, interfaces, classes
• Score = relevance (1 = best match)
• Calls = what this code calls (helps you trace flow)

When to Read more

The snippet often has enough context. But if you need more:

# osgrep found src/auth/handler.ts:45-90 as ORCH
Read src/auth/handler.ts:45-120

Read the specific line range, not the whole file.

Other commands

# Trace call graph (who calls X, what X calls)
osgrep trace handleAuth

# Skeleton of a huge file (to find which ranges to read)
osgrep skeleton src/giant-2000-line-file.ts

# Just file paths when you only need locations
osgrep "authentication" --compact

Workflow: architecture questions

# 1. Find entry points
osgrep "where do requests enter the server"
# Review the ORCH results - code is shown

# 2. If you need deeper context on a specific function
Read src/server/handler.ts:45-120

# 3. Trace to understand call flow
osgrep trace handleRequest

Tips

• More words = better results. "auth" is vague. "where does the server validate JWT tokens" is specific.
• ORCH results contain the logic - prioritize these
• Don't read entire files. Use the line ranges osgrep gives you.
• If results seem off, rephrase your query like you'd ask a teammate

If Index is Building

If you see "Indexing" or "Syncing": STOP. Tell the user the index is building. Ask if they want to wait or proceed with partial results.