The GitHub MCP server provides 32 tools across issue and pull request management. Strengths: tool naming is consistently verb-based and clear (create_issue, update_issue_title, etc.); descriptions are present and contextual for most tools; input schemas are well-structured with proper JSON Schema syntax; tool annotations (risk levels: READ_ONLY, WRITE, DESTRUCTIVE) are declared. Weaknesses: descriptions are often brief (50-120 chars) and lack actionable context about when to use each tool vs. alternatives; many parameter descriptions are minimal (e.g., 'Issue number', 'Reaction type'); no output schemas are documented in the visible code; error handling guidance is absent; several tools expose overlapping responsibilities without clear composition hints (e.g., 10 separate update_issue_* tools rather than a single update_issue with a fields map); no enumerated constraints on parameters like 'state', 'reaction', or 'event', these accept free-form strings. Tool definitions appear to be registered via test files (__toolsnaps__) rather than explicit implementation visibility, which limits confidence in schema completeness.

• Consolidate granular issue/PR update tools. Replace update_issue_title, update_issue_body, update_issue_assignees, etc., with a single update_issue(owner, repo, issue_number, updates: {title?, body?, assignees?, labels?, milestone?, state?}) tool that accepts partial updates. This reduces tool count, enables atomic multi-field updates, and simplifies agent reasoning.
• Add enum constraints for all enum-like parameters. Declare valid values for 'state' (open|closed), 'event' (COMMENT|APPROVE|REQUEST_CHANGES|PENDING|COMMENTED), 'reaction' (thumbsup|thumbsdown|laugh|confused|heart|rocket|eyes), etc. in the parameter schema and description.
• Document output schemas for all tools. For each tool, add a 'Returns' section describing: fields returned, their types, which IDs are included for chaining (e.g., issue_id, pull_request_id). Make explicit what the LLM can extract and pass to downstream tools.
• Expand descriptions to 100-200 characters. Rewrite each tool description to answer: (1) What does it do? (2) When should the agent use it (vs. similar tools)? (3) Are there prerequisites? Example: 'Update multiple fields of an issue in a single call. Use this instead of separate update_issue_title/update_issue_body calls for efficiency. Requires the issue to exist.'
• Add error guidance to descriptions. State what errors are likely (Invalid request, Resource not found, Permission denied) and what to do: 'Returns 404 if issue does not exist. Verify owner, repo, and issue_number; or call list_issues to find the correct issue_number.'