Using Templates
Templates give you a working agent in seconds. Start from a proven foundation, then customize.
Available Templates
| Template | Description | Best For |
|---|
default | Coding agent with file/bash tools | General purpose, coding tasks |
research-agent | Web search and document synthesis | Research, reports, analysis |
support-agent | Ticket handling and escalation | Customer support workflows |
mcp-tools | Custom tool integration example | Learning MCP patterns |
Using cast init
Interactive prompt:
? Select a template:
❯ default — Coding agent with file and bash tools (like Claude Code)
research-agent — Deep research with web search and document synthesis
support-agent — Customer support with ticket handling and escalation
mcp-tools — Agent with example MCP server integration
Skip the prompt
cast init my-agent --template research-agent
Template Structure
Every template includes:
my-agent/
├── castari.json # Agent configuration
├── package.json # Dependencies
├── tsconfig.json # TypeScript config
├── src/
│ └── index.ts # Agent entry point with tools
├── CLAUDE.md # Agent instructions
└── README.md # Documentation
Template: default
A Claude Code-style agent with file and bash tools.
Tools included:
| Tool | Description |
|---|
read_file | Read file contents |
write_file | Create/update files |
bash | Execute shell commands |
list_files | List directory contents |
cast invoke my-agent "What files are here?"
cast invoke my-agent "Create a hello.py that prints Hello World"
cast invoke my-agent "Run the tests"
Template: research-agent
Deep research with web search and document synthesis.
Tools included:
| Tool | Description |
|---|
web_search | Search the web |
read_url | Fetch and read web pages |
save_report | Save findings to file |
read_file | Read local documents |
cast invoke my-agent "Research the current state of AI agents in 2026"
cast invoke my-agent "Compare AWS, GCP, and Azure for serverless"
The research-agent template includes a mock web search. For production, integrate with SerpAPI, Tavily, or similar.
Template: support-agent
Customer support with ticket handling.
Tools included:
| Tool | Description |
|---|
lookup_user | Find user by email/ID |
lookup_order | Find order details |
create_ticket | Escalate to human |
send_response | Reply to customer |
cast invoke my-agent "I need help with order #12345"
cast invoke my-agent "How do I reset my password?"
Example of custom MCP tool integration.
Tools included:
| Tool | Description |
|---|
calculate | Math calculations |
get_weather | Weather lookup (mock) |
query_database | Database queries (mock) |
send_notification | Send alerts |
- How to define tool schemas
- How to implement tool handlers
- How to integrate external services
Best for: Learning tool development, prototyping custom integrations.
Customizing Templates
1. Edit CLAUDE.md
The CLAUDE.md file contains agent instructions:
# My Agent
You are a helpful assistant that...
## Guidelines
- Be concise
- Always explain before acting
- Ask for clarification when unsure
src/index.ts to add, remove, or modify tools:
const tools: Anthropic.Tool[] = [
{
name: "my_custom_tool",
description: "Does something useful",
input_schema: {
type: "object",
properties: {
input: { type: "string" }
},
required: ["input"]
}
}
];
3. Add Dependencies
npm install axios # Example: add HTTP client
import axios from 'axios';
// In your tool handler
const response = await axios.get('https://api.example.com/data');
4. Redeploy
After changes:
See Also
