Morph WarpGrep & Fast Apply

Morph provides two tools that significantly improve coding agent performance:

• WarpGrep: Agentic code search that's 5x faster than regular search, uses parallel tool calls, achieves 0.73 F1 in ~4 steps
• Fast Apply: Merges AI edits into code at 10,500 tok/s with 98% accuracy (2x faster than search-replace)

Prerequisites

1. Get a Morph API key from https://www.morphllm.com/dashboard
2. Set environment variable:

export MORPH_API_KEY="your-api-key"

3. Install the Morph SDK:

bun add @morphllm/morphsdk
# or
npm install @morphllm/morphsdk

4. Ensure ripgrep is installed (required for local search):

# macOS
brew install ripgrep

# Ubuntu/Debian  
sudo apt install ripgrep

# Verify installation
rg --version

Quick Test

After setup, run the included test script on any local repository:

# Clone a test repo (or use any existing codebase)
git clone https://github.com/letta-ai/letta-code.git test-repo

# Install SDK
cd test-repo
bun add @morphllm/morphsdk

# Run test script
export MORPH_API_KEY="your-key"
bun ../scripts/test-warpgrep.ts .

Expected output:

======================================================================
MORPH WARPGREP TEST
======================================================================
Repo: .
SDK: @morphllm/morphsdk
======================================================================

| Query                              | Result | Time   | Files |
|------------------------------------|--------|--------|-------|
| Find the main entry point          | ✅     | 5.2s   | 2     |
| Find authentication logic          | ✅     | 4.1s   | 4     |
| Find where configuration is handled | ✅     | 3.8s   | 3     |
| Find error handling patterns       | ✅     | 4.5s   | 5     |

======================================================================
Results: 4 passed, 0 failed
======================================================================

---

When to Use

Use WarpGrep When:

• Searching large codebases (1000+ files)
• Deep logic queries: bug tracing, code paths, control flow analysis
• Need to find relevant context without polluting the context window
• Regular grep returns too many irrelevant results

Use Fast Apply When:

• Applying AI-generated code edits to existing files
• Need reliable edit merging (98% accuracy vs ~70% for search-replace)
• Working with large files where diff formats fail

Don't Use When:

• Simple exact-match searches (regular grep/rg is free and fast enough)
• Surface-level queries where semantic search suffices
• Cost is a major concern (Morph API has usage costs)

---

Quick Start: WarpGrep

Basic Usage

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: process.env.MORPH_API_KEY });

const result = await morph.warpGrep.execute({
  query: 'Find authentication middleware',
  repoRoot: '.'
});

if (result.success) {
  for (const ctx of result.contexts) {
    console.log(`File: ${ctx.file}`);
    console.log(ctx.content);
  }
} else {
  console.error('Search failed');
}

Response Format

interface WarpGrepResult {
  success: boolean;
  contexts: Array<{
    file: string;    // File path relative to repo root
    content: string; // File content with relevant code
  }>;
  summary?: string;  // Human-readable summary
}

Using as an Agent Tool

import { MorphClient } from '@morphllm/morphsdk';
import Anthropic from '@anthropic-ai/sdk';

const morph = new MorphClient({ apiKey: process.env.MORPH_API_KEY });
const anthropic = new Anthropic();

// Define WarpGrep as a tool
const tools = [{
  name: 'warpgrep_search',
  description: 'Search codebase for relevant code. Use for finding implementations, tracing bugs, or understanding code flow.',
  input_schema: {
    type: 'object',
    properties: {
      query: { type: 'string', description: 'What to search for' }
    },
    required: ['query']
  }
}];

// Handle tool calls
async function handleToolCall(name: string, input: { query: string }) {
  if (name === 'warpgrep_search') {
    const result = await morph.warpGrep.execute({
      query: input.query,
      repoRoot: process.cwd()
    });
    
    if (result.success) {
      return result.contexts.map(c => `## ${c.file}\n${c.content}`).join('\n\n');
    }
    return 'No results found';
  }
}

---

Quick Start: Fast Apply

Fast Apply merges AI-generated edits into existing code:

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: process.env.MORPH_API_KEY });

const result = await morph.fastApply.apply({
  originalCode: `function divide(a, b) {
  return a / b;
}`,
  editSnippet: `function divide(a, b) {
  if (b === 0) throw new Error("Division by zero");
  return a / b;
}`
});

console.log(result.mergedCode);

Direct API (Alternative)

const response = await fetch('https://api.morphllm.com/v1/chat/completions', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${process.env.MORPH_API_KEY}`
  },
  body: JSON.stringify({
    model: 'morph-v3-fast',  // or 'morph-v3-large' for complex edits
    messages: [{
      role: 'user',
      content: `<instruction>Add error handling</instruction>
<code>function divide(a, b) { return a / b; }</code>
<update>function divide(a, b) {
  if (b === 0) throw new Error("Division by zero");
  return a / b;
}</update>`
    }],
    temperature: 0
  })
});

const data = await response.json();
const mergedCode = data.choices[0].message.content;

---

Tested Results

Tested on the letta-code repository (~300 TypeScript files) using SDK v0.2.103:

Query	Result	Time	Files Found
"Find authentication logic"	✅	4.2s	src/auth/oauth.ts, src/auth/setup.ts, +2
"Find the main CLI entry point"	✅	5.8s	src/index.ts, src/cli/App.tsx
"Find where models are configured"	✅	3.1s	src/agent/model.ts, src/models.json, +1
"Find how memory blocks work"	✅	3.9s	src/agent/memory.ts, src/agent/memoryFilesystem.ts, +1
"Find the settings manager"	✅	2.9s	src/settings-manager.ts, src/settings.ts

5/5 tests passed

Performance Summary

• Average time: 4.0 seconds
• Token efficiency: 39% fewer input tokens vs manual search
• Accuracy: Finds relevant code in 2-4 turns

---

How WarpGrep Works

WarpGrep is an agentic search that runs up to 4 turns:

┌─────────────────────────────────────────────────────────────┐
│  Turn 1: Analyze query, map repo structure, initial search  │
├─────────────────────────────────────────────────────────────┤
│  Turn 2-3: Refine search, read specific files               │
├─────────────────────────────────────────────────────────────┤
│  Turn 4: Return all relevant code locations                 │
└─────────────────────────────────────────────────────────────┘

The SDK handles the multi-turn conversation automatically, executing local tools:

Tool	Description	Implementation
grep	Regex search across files	Uses ripgrep (rg)
read	Read file contents	Local filesystem
list_dir	Show directory structure	Local filesystem

---

Architecture

┌──────────────────────────────────────────────────────────────┐
│                    Your Code / Agent                         │
└──────────────────────────┬───────────────────────────────────┘
                           │
                           ▼
┌──────────────────────────────────────────────────────────────┐
│              @morphllm/morphsdk                              │
│  ┌─────────────────────────────────────────────────────────┐ │
│  │ 1. Build repo structure                                 │ │
│  │ 2. Send query to Morph API                              │ │
│  │ 3. Execute local tools (grep, read, list_dir)           │ │
│  │ 4. Multi-turn refinement                                │ │
│  │ 5. Return relevant code contexts                        │ │
│  └─────────────────────────────────────────────────────────┘ │
└──────────────────────────┬───────────────────────────────────┘
                           │
            ┌──────────────┴──────────────┐
            ▼                             ▼
┌───────────────────────┐    ┌───────────────────────┐
│    Morph API          │    │   Local Filesystem    │
│  (morph-warp-grep-v1) │    │   (ripgrep, fs)       │
└───────────────────────┘    └───────────────────────┘

---

Morph's Benchmarks

From Morph's SWE-bench evaluation with Claude 4.5 Opus:

Metric	Without WarpGrep	With WarpGrep	Improvement
Input Tokens	14K	9K	39% fewer
Agent Turns	35.0	26.0	26% fewer
Tasks Solved	74.4%	81.9%	10% more

Source: Morph WarpGrep Benchmarks

---

Common Patterns

Reconnaissance-Then-Action

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: process.env.MORPH_API_KEY });

// 1. Search for relevant code
const result = await morph.warpGrep.execute({
  query: 'Where is the payment processing logic?',
  repoRoot: '.'
});

// 2. Use found contexts to inform next steps
if (result.success) {
  const relevantFiles = result.contexts.map(c => c.file);
  console.log('Found relevant files:', relevantFiles);
  // Now read/edit these specific files
}

Combining WarpGrep + Fast Apply

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: process.env.MORPH_API_KEY });

// 1. Find the code to modify
const search = await morph.warpGrep.execute({
  query: 'Find the user validation function',
  repoRoot: '.'
});

if (search.success && search.contexts.length > 0) {
  const targetFile = search.contexts[0];
  
  // 2. Apply an edit
  const result = await morph.fastApply.apply({
    originalCode: targetFile.content,
    editSnippet: '// Add your modified version here'
  });
  
  console.log(result.mergedCode);
}

---

MCP Integration

For personal use with Claude Code, Cursor, or other MCP clients:

# Install MCP server
claude mcp add morph --scope user -e MORPH_API_KEY=YOUR_API_KEY --npx -y @morphllm/morphmcp

This adds a warpgrep_codebase_search tool to your MCP client.

---

Troubleshooting

ripgrep Not Found

# Install ripgrep
brew install ripgrep  # macOS
sudo apt install ripgrep  # Ubuntu/Debian

# Verify
rg --version

API Key Issues

# Verify API key works
curl -X POST https://api.morphllm.com/v1/chat/completions \
  -H "Authorization: Bearer $MORPH_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"morph-v3-fast","messages":[{"role":"user","content":"test"}]}'

SDK Version Issues

Ensure you're using the latest SDK:

bun add @morphllm/morphsdk@latest
# or
npm install @morphllm/morphsdk@latest

---

Cost Considerations

• WarpGrep uses 1-4 API calls per search (typically 2-3)
• Fast Apply uses 1 API call per edit
• Pricing: $0.80 per 1M tokens (input and output)
• Monitor usage via Morph Dashboard
• Use regular grep/ripgrep for simple exact-match searches (free)

---

Resources

• Morph Documentation
• WarpGrep Guide
• WarpGrep Benchmarks
• Fast Apply Benchmarks
• Morph Dashboard
• Morph Discord