Claude Agent SDK Guide

Build custom AI agents powered by Claude. Same infrastructure as Claude Code.

Installation

TypeScript

npm install @anthropic-ai/claude-agent-sdk

Python

pip install claude-agent-sdk

Core Features

Context Management

Automatic compaction ensures your agent doesn't run out of context during extended operations.

Tool Ecosystem

Built-in capabilities:

• File operations - Read, write, edit files

• Code execution - Run bash commands safely

• Web search - Access real-time information

• MCP extensibility - Add custom tools via Model Context Protocol

Permission Controls

{ allowedTools: ['Read', 'Write', 'Bash'], // Explicit allowlist disallowedTools: ['WebSearch'], // Explicit blocklist permissionMode: 'default' | 'strict' // Overall strategy }

Authentication Providers

Anthropic API (Default)

export ANTHROPIC_API_KEY=sk-ant-...

Amazon Bedrock

export CLAUDE_CODE_USE_BEDROCK=1 export AWS_ACCESS_KEY_ID=... export AWS_SECRET_ACCESS_KEY=... export AWS_REGION=us-east-1

Google Vertex AI

export CLAUDE_CODE_USE_VERTEX=1 export GOOGLE_APPLICATION_CREDENTIALS=/path/to/credentials.json export VERTEX_REGION=us-central1 export VERTEX_PROJECT_ID=your-project

Microsoft Foundry

export CLAUDE_CODE_USE_FOUNDRY=1

Azure credentials configuration

File-Based Configuration

Directory Purpose

.claude/agents/

Subagent definitions (Markdown)

.claude/skills/

Skill files (SKILL.md )

.claude/commands/

Slash commands (Markdown)

.claude/settings.json

Hooks configuration

CLAUDE.md

Project memory/context

Enable project settings:

{ settingSources: ['project'] }

Code Examples

TypeScript: Basic Agent

import { Agent } from '@anthropic-ai/claude-agent-sdk';

const agent = new Agent({ model: 'claude-sonnet-4-20250514', allowedTools: ['Read', 'Write', 'Bash'], systemPrompt: You are a code review assistant. Analyze code for bugs, security issues, and best practices., });

const result = await agent.run({ prompt: 'Review the code in src/auth.ts for security issues', });

console.log(result.output);

TypeScript: Agent with MCP Tools

import { Agent } from '@anthropic-ai/claude-agent-sdk';

const agent = new Agent({ model: 'claude-sonnet-4-20250514', mcpServers: { database: { command: 'npx', args: ['-y', '@modelcontextprotocol/server-postgres'], env: { DATABASE_URL: process.env.DATABASE_URL }, }, }, });

const result = await agent.run({ prompt: 'List all users who signed up in the last 24 hours', });

Python: Basic Agent

from claude_agent_sdk import Agent

agent = Agent( model="claude-sonnet-4-20250514", allowed_tools=["Read", "Write", "Bash"], system_prompt="""You are a code review assistant. Analyze code for bugs, security issues, and best practices.""", )

result = agent.run( prompt="Review the code in src/auth.py for security issues" )

print(result.output)

Python: Agent with Custom Permissions

from claude_agent_sdk import Agent, PermissionMode

agent = Agent( model="claude-sonnet-4-20250514", permission_mode=PermissionMode.STRICT, allowed_tools=["Read", "Grep", "Glob"], disallowed_tools=["Bash"], # Extra safety )

result = agent.run( prompt="Find all TODO comments in the codebase" )

Agent Types & Use Cases

Coding Agents

• SRE Diagnostics - Analyze logs, identify issues, suggest fixes

• Security Auditing - Scan for vulnerabilities, check dependencies

• Incident Triage - Correlate alerts, gather context, draft runbooks

• Code Review - Enforce standards, catch bugs, suggest improvements

Business Agents

• Legal Review - Analyze contracts, flag risks, summarize terms

• Financial Analysis - Process reports, identify anomalies, forecast

• Customer Support - Handle tickets, route issues, draft responses

• Content Creation - Generate docs, edit copy, ensure consistency

Best Practices

Start Simple

Begin with minimal tool access and expand as needed:

// Start here allowedTools: ['Read']

// Then add as required allowedTools: ['Read', 'Grep', 'Glob']

// Only if truly needed allowedTools: ['Read', 'Write', 'Bash']

Use Subagents for Complex Tasks

Break large tasks into specialized subagents:

.claude/agents/ ├── code-reviewer.md # Reviews code changes ├── test-writer.md # Generates tests └── doc-generator.md # Creates documentation

Handle Errors Gracefully

try { const result = await agent.run({ prompt }); if (result.error) { console.error('Agent error:', result.error); } } catch (error) { console.error('SDK error:', error); }

Monitor Agent Behavior

const agent = new Agent({ onToolUse: (tool, input) => { console.log(Tool: ${tool}, Input: ${JSON.stringify(input)}); }, onThinking: (thought) => { console.log(Thinking: ${thought}); }, });

Project Scaffolding

Use /agent-sdk:agent-scaffold command to generate a new project.

Template Files

Template Purpose

assets/typescript/package.json

Node.js package config

scripts/typescript/agent.ts

TypeScript agent entry

assets/python/pyproject.toml

Python package config

scripts/python/agent.py

Python agent entry

assets/env-*.example

Provider config templates

references/claude/*.md

Subagent/skill/command templates

Tool Mapping

User Selection SDK Tools

File Operations Read, Write, Edit, Glob, Grep

Code Execution Bash

Web Search WebSearch, WebFetch

MCP Tools (configured via mcpServers)

System Prompts

Coding Agent:

You are a coding assistant that helps developers write better code. Analyze code for bugs, security issues, and best practices.

Business Agent:

You are a business analyst assistant. Help with document analysis, data extraction, and report generation.

Resources

• TypeScript: anthropics/claude-agent-sdk-typescript

• Python: anthropics/claude-agent-sdk-python

• Docs: platform.claude.com/docs/en/agent-sdk/overview