List Agent Tools

List available tools for custom agent configuration.

Instructions

Display the default Claude Code tools and guidance for tool access configuration.

Output

## Claude Code Default Tools

### File Operations

| Tool | Purpose | Common Use |
| --- | --- | --- |
| `Read` | Read file contents | Codebase exploration |
| `Write` | Write new files | File creation |
| `Edit` | Edit existing files | Code modification |
| `Glob` | Find files by pattern | File discovery |
| `Grep` | Search file contents | Code search |

### Execution

| Tool | Purpose | Common Use |
| --- | --- | --- |
| `Bash` | Execute shell commands | Build, test, deploy |

### Web

| Tool | Purpose | Common Use |
| --- | --- | --- |
| `WebFetch` | Fetch web content | Documentation |
| `WebSearch` | Search the web | Research |

### Agent

| Tool | Purpose | Common Use |
| --- | --- | --- |
| `Task` | Spawn subagents | Parallel work |
| `TodoWrite` | Track tasks | Progress tracking |

---

## Tool Access Configuration

### Whitelist (allowed_tools)

Use when agent needs only specific tools:

```python
allowed_tools=["Read", "Write", "Bash"]

Blacklist (disallowed_tools)

Use when agent needs most tools except some:

disallowed_tools=["WebFetch", "WebSearch", "Task"]

Disable All Default Tools

For agents with only custom tools:

disallowed_tools=["*"]

Custom Tools

Add via MCP server:

mcp_servers={"my_server": my_mcp_server}
allowed_tools=["mcp__my_server__my_tool"]

Tool naming: mcp__<server>__<tool>

---

Tool Access Patterns

Minimal Agent

For focused, single-purpose agents:

allowed_tools=["Read"]  # Read-only exploration

Code Agent

For agents that modify code:

allowed_tools=["Read", "Write", "Edit", "Glob", "Grep", "Bash"]

Research Agent

For agents that gather information:

allowed_tools=["Read", "Glob", "Grep", "WebFetch", "WebSearch"]

Pure Custom Tools

For agents with only custom functionality:

mcp_servers={"domain": domain_server}
allowed_tools=["mcp__domain__tool1", "mcp__domain__tool2"]
disallowed_tools=["*"]

Parallel Agent

For agents that spawn subagents:

allowed_tools=["Task", "Read", "Glob", "Grep"]

---

Token Overhead Warning

"15 extra tools consume space in your agent's mind."

Each tool definition consumes context window space even if never used. Strip unnecessary tools for:

• Better context utilization
• Reduced confusion
• Clearer agent focus

---

Related Commands

• /create-agent - Scaffold new custom agent
• /create-tool - Generate custom tool boilerplate

Related Skills

• @custom-agent-design - Agent design workflow
• @tool-design - Tool creation workflow

Related Memory

• @core-four-custom.md - Tools in Core Four
• @custom-tool-patterns.md - Tool patterns

Notes

• Use /context command to understand tool overhead
• Strip tools your agent doesn't need
• Custom tools require ClaudeSDKClient (not query())