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# Start Claude Code as an MCP server (stdio transport)
claude mcp serve

npm install -g @anthropic-ai/mcpb

mcpb init my-server
cd my-server
mcpb build
mcpb install   # installs the bundle into Claude Code

# Add Claude Code as an MCP server inside another MCP client
claude mcp add claude-code -- claude mcp serve

{
  "mcpServers": {
    "anthropic-code": {
      "command": "claude",
      "args": ["mcp", "serve"],
      "env": {}
    }
  }
}

npm install -g @anthropic-ai/claude-code

# Start interactive session
claude

# Run a one-shot prompt (non-interactive)
claude -p "Explain the auth flow in src/auth.ts"

# Run with a specific model
claude --model claude-opus-4-7

# Continue the most recent session
claude --continue

# Run a bash command within a Claude session
claude -p "Fix the TypeScript errors" --allowedTools Bash,Edit,Write

# Start as MCP server
claude mcp serve

# Manage MCP servers
claude mcp add <name> -- <command> [args]
claude mcp list
claude mcp remove <name>

# Add remote MCP server (HTTP transport)
claude mcp add --transport http my-server https://my-server.example.com/mcp

npm install @anthropic-ai/sdk

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({ apiKey: process.env.ANTHROPIC_API_KEY });

const message = await client.messages.create({
  model: "claude-sonnet-4-6",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Review this code for security issues." }],
});

console.log(message.content[0].text);

pip install anthropic

import anthropic

client = anthropic.Anthropic(api_key=os.environ["ANTHROPIC_API_KEY"])

message = client.messages.create(
    model="claude-sonnet-4-6",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Generate unit tests for this function."}],
)
print(message.content[0].text)

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic();

const message = await client.messages.create({
  model: "claude-sonnet-4-6",
  max_tokens: 1024,
  // Cache the tool set — tools render at position 0, so this prefix is reused first.
  tools: [
    {
      name: "search_orders",
      description: "Look up M-Pesa orders by phone number.",
      input_schema: {
        type: "object",
        properties: { phone: { type: "string" } },
        required: ["phone"],
      },
      cache_control: { type: "ephemeral" },
    },
  ],
  // Cache the large, frozen system prompt — breakpoint on the LAST block caches tools + system together.
  system: [
    {
      type: "text",
      text: LARGE_SHARED_PROMPT, // e.g. product catalog, brand rules, RAG context
      cache_control: { type: "ephemeral" }, // add `ttl: "1h"` for bursty traffic with idle gaps
    },
  ],
  // Volatile content goes last, after the cached prefix — no marker here.
  messages: [{ role: "user", content: "Where is my last order?" }],
});

// Confirm it worked — cache_read_input_tokens should be > 0 on the 2nd+ identical-prefix call.
console.log(message.usage.cache_read_input_tokens, message.usage.cache_creation_input_tokens);

# Required
ANTHROPIC_API_KEY=sk-ant-...

# Optional overrides
ANTHROPIC_BASE_URL=https://api.anthropic.com    # default
ANTHROPIC_MODEL=claude-sonnet-4-6               # default model for claude CLI
ANTHROPIC_MAX_TOKENS=8096                        # default max tokens

# Claude Code specific
CLAUDE_CODE_MAX_OUTPUT_TOKENS=32000

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "echo 'Tool: Bash about to run' >> .claude/audit.log"
          }
        ]
      }
    ],
    "PostToolUse": [
      {
        "matcher": "Write",
        "hooks": [
          {
            "type": "command",
            "command": "npx prettier --write $CLAUDE_FILE_PATH 2>/dev/null || true"
          }
        ]
      }
    ],
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "node scripts/notify-complete.js"
          }
        ]
      }
    ]
  }
}

mkdir -p .claude/commands

Review the following code for: security issues, performance problems, and code quality.
Focus on: $ARGUMENTS
Provide actionable fixes with code examples.

// scripts/ai-review.ts
import Anthropic from "@anthropic-ai/sdk";
import { readFileSync } from "fs";

const client = new Anthropic();
const diff = readFileSync("latest.diff", "utf-8");

const review = await client.messages.create({
  model: "claude-sonnet-4-6",
  max_tokens: 2048,
  system: "You are a senior code reviewer. Be concise and actionable.",
  messages: [{ role: "user", content: `Review this diff:\n\n${diff}` }],
});

console.log(review.content[0].text);

# Project Context

## Tech Stack
- TypeScript, Node.js 22, PostgreSQL
- Test runner: Vitest
- Linter: ESLint + Prettier

## Conventions
- Use `async/await` — no raw Promises
- All functions must have JSDoc comments
- Tests go in `__tests__/` next to source files

## Forbidden
- Never use `any` type
- Never commit `.env` files