/add-custom-tools

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🚨 EXECUTION NOTICE FOR CLAUDE

When you invoke this command via SlashCommand, the system returns THESE INSTRUCTIONS below.

YOU are the executor. This is NOT an autonomous subprocess.

• ✅ The phases below are YOUR execution checklist
• ✅ YOU must run each phase immediately using tools (Bash, Read, Write, Edit, TodoWrite)
• ✅ Complete ALL phases before considering this command done
• ❌ DON't wait for "the command to complete" - YOU complete it by executing the phases
• ❌ DON't treat this as status output - it IS your instruction set

Immediately after SlashCommand returns, start executing Phase 0, then Phase 1, etc.

See @CLAUDE.md section "SlashCommand Execution - YOU Are The Executor" for detailed explanation.

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Available Skills

This commands has access to the following skills from the claude-agent-sdk plugin:

• fastmcp-integration: Examples and patterns for integrating FastMCP Cloud servers with Claude Agent SDK using HTTP transport
• sdk-config-validator: Validates Claude Agent SDK configuration files, environment setup, dependencies, and project structure

To use a skill:

!{skill skill-name}

Use skills when you need:

• Domain-specific templates and examples
• Validation scripts and automation
• Best practices and patterns
• Configuration generators

Skills provide pre-built resources to accelerate your work.

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Security Requirements

CRITICAL: All generated files must follow security rules:

@docs/security/SECURITY-RULES.md

Key requirements:

• Never hardcode API keys or secrets
• Use placeholders: your_service_key_here
• Protect .env files with .gitignore
• Create .env.example with placeholders only
• Document key acquisition for users

Arguments: $ARGUMENTS

Goal: Add custom tool definitions to an existing Claude Agent SDK application

Core Principles:

• Understand existing code before modifying
• Load SDK documentation for custom tool patterns
• Follow official SDK examples

Phase 1: Discovery Goal: Gather context about the project

Actions:

• Load SDK custom tools documentation: Read SDK documentation: ~/.claude/plugins/marketplaces/ai-dev-marketplace/plugins/claude-agent-sdk/docs/sdk-documentation.md
• Check if project path provided in $ARGUMENTS
• Read package.json or requirements.txt to confirm SDK is installed
• Identify main application files
• Ask user what custom tools to add

Phase 2: Analysis Goal: Understand current implementation

Actions:

• Read main application files
• Check if custom tools are already defined
• Identify query() function configuration
• Determine language (TypeScript or Python)

Phase 3: Planning Goal: Design custom tools

Actions:

• Define tool schemas and parameters
• Plan tool implementation functions
• Identify files to modify
• Present plan to user for confirmation

Phase 4: Implementation Goal: Add custom tools with agent

Actions:

Invoke the claude-agent-features agent to add custom tools.

The agent should:

• Fetch custom tools documentation: https://docs.claude.com/en/api/agent-sdk/custom-tools
• Create tool definitions with proper schemas
• Implement tool() function calls
• Add tool permissions configuration
• Add error handling for tool execution

Provide the agent with:

• Context: Project language, structure, and desired tools
• Target: $ARGUMENTS (project path)
• Expected output: Updated files with custom tool definitions

Phase 5: Review Goal: Verify custom tools work correctly

Actions:

• Invoke appropriate verifier agent:
  • TypeScript: claude-agent-verifier-ts
  • Python: claude-agent-verifier-py
• Check that tool schemas are valid
• Verify tools can be invoked properly

Phase 6: Summary Goal: Document what was added

Actions:

• Summarize custom tools added
• Show example tool usage
• Link to SDK custom tools documentation
• Suggest testing with tool calls