Describe the feature or problem you’d like to solve

After limiting "GITHUB_TOOLSETS": "issues,pull_requests,repos", there are still too many tools available

Benefits:

• avoid pollute context window
• avoid unwanted, dangerous tools (e.g., merge_pull_request)

Some example use cases:

• In some use cases, I only want the MCP to do research, so I want "read only" tools, e.g., search issues, search PRs. No need to use update/create tools at all.
• Sometimes it's write only, e.g., "create an issue for me"
• In tools like cursor, it has native search_code tool, so it's duplicative.

Proposed solution

• allow tool level selection --tools
• Or maybe add ability to disable tools, if you think that's better. --disable-tools