semtools

# Semtools: Semantic Search

Perform semantic (meaning-based) search across code and documents using embedding-based similarity matching.

## Purpose

The semtools skill provides access to Semtools, a high-performance Rust-based CLI for semantic search and document processing. Unlike traditional text search (ripgrep) which matches exact strings, or structural search (ast-grep) which matches syntax patterns, semtools understands **semantic meaning** through embeddings.

**Key capabilities:**

1. **Semantic Search**: Find code/text by meaning, not just keywords
2. **Workspace Management**: Index large codebases for fast repeated searches
3. **Document Parsing**: Convert PDFs, DOCX, PPTX to searchable text (requires API key)

Semtools excels at **discovery** - finding relevant code when you don't know the exact keywords, function names, or syntax patterns.

## When to Use This Skill

Use the semtools skill when you need meaning-based search:

**Semantic Code Discovery:**
- Finding code that implements a concept ("error handling", "data validation")
- Discovering similar functionality across different modules
- Locating examples of a pattern when you don't know exact names
- Understanding what code does without reading everything

**Documentation & Knowledge:**
- Searching documentation by concept, not keywords
- Finding related discussions in comments or docs
- Discovering similar issues or solutions
- Analyzing technical documents (PDFs, reports)

**Use Cases:**
- "Find all authentication-related code" (without knowing function names)
- "Show me error handling patterns" (regardless of specific error types)
- "Find code similar to this implementation" (semantic similarity)
- "Search research papers for 'distributed consensus'" (document search)

**Choose semtools over file-search (ripgrep/ast-grep) when:**
- You know the **concept** but not the **keywords**
- Exact string matching misses relevant results
- You want semantically similar code, not exact matches
- Searching across languages or mixed content

**Still use file-search when:**
- You know exact keywords, function names, or patterns
- You need structural code matching (ast-grep)
- Speed is critical (ripgrep is faster for exact matches)
- You're searching for specific symbols or references

## Available Commands

Semtools provides three CLI commands you can use via `execute_command`:

- **`search`** - Semantic search across code and text files
- **`workspace`** - Manage workspaces for caching embeddings
- **`parse`** - Convert documents (PDF, DOCX, PPTX) to searchable text

**All commands work out-of-the-box** in your execution environment. Document parsing requires the LLAMA_CLOUD_API_KEY environment variable to be set.

## Core Operations

### 1. Semantic Search (`search`)

Find files and code sections by semantic meaning:

```bash
# Basic semantic search
search "authentication logic" src/

# Search with more context (5 lines before/after)
search "error handling" --n-lines 5 src/

# Get more results (default: 3)
search "database queries" --top-k 10 src/

# Control similarity threshold (0.0-1.0, lower = more lenient)
search "API endpoints" --max-distance 0.4 src/
```

**Parameters:**
- `--n-lines N`: Show N lines of context around matches (default: 3)
- `--top-k K`: Return top K most similar matches (default: 3)
- `--max-distance D`: Maximum embedding distance (0.0-1.0, default: 0.3)
- `-i`: Case-insensitive matching

**Output format:**
```
Match 1 (similarity: 0.12)
File: src/auth/handlers.py
Lines: 42-47
----
def authenticate_user(username: str, password: str) -> Optional[User]:
    """Authenticate user credentials against database."""
    user = get_user_by_username(username)
    if user and verify_password(password, user.password_hash):
        return user
    return None
----

Match 2 (similarity: 0.18)
File: src/middleware/auth.py
...
```

### 2. Workspace Management (`workspace`)

For large codebases, create workspaces to cache embeddings and enable fast repeated searches:

```bash
# Create/activate workspace
workspace use my-project

# Set workspace via environment variable
export SEMTOOLS_WORKSPACE=my-project

# Index files in workspace (workspace auto-detected from env var)
search "query" src/

# Check workspace status
workspace status

# Clean up old workspaces
workspace prune
```

**Benefits:**
- **Fast repeated searches**: Embeddings cached, no re-computation
- **Large codebases**: IVF_PQ indexing for scalability
- **Session persistence**: Maintain context across multiple searches

**When to use workspaces:**
- Searching the same codebase multiple times
- Very large projects (1000+ files)
- Interactive exploration sessions
- CI/CD pipelines with repeated searches

### 3. Document Parsing (`parse`) ⚠️ Requires API Key

Convert documents to searchable markdown (requires LlamaParse API key):

```bash
# Parse PDFs to markdown
parse research_papers/*.pdf

# Parse Word documents
parse reports/*.docx

# Parse presentations
parse slides/*.pptx

# Parse and pipe to search
parse docs/*.pdf | xargs search "neural networks"
```

**Supported formats:**
- PDF (.pdf)
- Word (.docx)
- PowerPoint (.pptx)

**Configuration:**
```bash
# Via environment variable
export LLAMA_CLOUD_API_KEY="llx-..."

# Via config file
cat > ~/.parse_config.json << EOF
{
  "api_key": "llx-...",
  "max_concurrent_requests": 10,
  "timeout_seconds": 3600
}
EOF
```

**Important:** Document parsing is **optional**. Semantic search works without it.

## Workflow Patterns

### Pattern 1: Concept Discovery

When you know what you're looking for conceptually but not by name:

```bash
# Step 1: Broad semantic search
search "rate limiting implementation" src/

# Step 2: Review results, refine query
search "throttle requests per user" src/ --top-k 10

# Step 3: Use ripgrep for exact follow-up
rg "RateLimiter" --type py src/
```

### Pattern 2: Similar Code Finder

When you want to find code similar to a reference implementation:

```bash
# Step 1: Extract key concepts