feat: add list-tools command for standalone tool discovery

[eli0shin]

Summary

• Add new list-tools command that enables standalone tool discovery without starting a proxy server
• Extend CLI argument parsing to support the new list-tools mode
• Add comprehensive test coverage for the list-tools functionality
• Update type definitions to support different operation modes

Changes

Core Functionality

• Modified src/cli.ts: Added comprehensive list-tools command functionality including:

  • New parseListToolsArguments() function for handling list-tools specific argument parsing
  • New listTools() function that connects to target MCP servers, retrieves available tools, and applies filtering
  • Extended main CLI argument parsing to support list-tools as a subcommand
  • Added support for --enabled-tools and --disabled-tools filtering options in list-tools mode

• Modified src/types.ts: Extended ProxyConfig type with optional mode field to distinguish between proxy and list-tools operations

Test Coverage

• Added tests/list-tools.test.ts: Complete test suite covering:
  • Basic tool listing functionality
  • Tool filtering with --enabled-tools and --disabled-tools options
  • Error handling for missing target commands
  • Validation of mutually exclusive filter options
  • Server initialization error handling
  • Command line argument passing to target servers

Usage Examples

# List all available tools from a server
mcp-controller list-tools bun run server.ts

# List only specific tools
mcp-controller list-tools --enabled-tools add,subtract bun run server.ts

# List all tools except specific ones
mcp-controller list-tools --disabled-tools dangerous-tool bun run server.ts

Test Plan

• All existing tests continue to pass
• New list-tools command works with basic functionality
• Tool filtering works correctly with both enabled and disabled tools options
• Error handling works for invalid arguments and server connection issues
• Command line arguments are properly passed to target servers
• Mutually exclusive options are properly validated

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR adds a new list-tools command that enables standalone tool discovery without starting a proxy server. This allows users to inspect available tools from MCP servers before deciding how to configure the proxy.

Key changes:

• Add list-tools subcommand with tool filtering capabilities via --enabled-tools and --disabled-tools options
• Extend CLI argument parsing to handle the new operation mode
• Add comprehensive test coverage for the new functionality

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/cli.ts	Implements core list-tools functionality including argument parsing, server communication, and tool filtering
src/types.ts	Extends ProxyConfig type with optional mode field to distinguish operation modes
tests/list-tools.test.ts	Comprehensive test suite covering all list-tools functionality and edge cases
package.json	Minor script update for typecheck command
.github/workflows/ci.yml	New CI workflow configuration

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[Copilot]

Using non-null assertion operator (!) is risky here. Consider using optional chaining or a proper null check since the condition already verifies enabledTools exists.

Suggested change

	tools = tools.filter((tool: Tool) => config.enabledTools!.includes(tool.name));
	tools = tools.filter((tool: Tool) => config.enabledTools.includes(tool.name));

[Copilot]

Using non-null assertion operator (!) is risky here. Consider using optional chaining or a proper null check since the condition already verifies disabledTools exists.

Suggested change

	tools = tools.filter((tool: Tool) => !config.disabledTools!.includes(tool.name));
	tools = tools.filter((tool: Tool) => !config.disabledTools.includes(tool.name));

[Copilot]

The empty catch block silently ignores all parsing errors. Consider adding a comment explaining why this is intentional or log the error for debugging purposes.

Suggested change

	// Continue reading if this line wasn't valid JSON
	} catch (err) {
	// Continue reading if this line wasn't valid JSON
	process.stderr.write(`Warning: Could not parse line as JSON: ${err instanceof Error ? err.message : String(err)}\n`);