Single tool 'rename_session' has a clear, verb-based name and adequate description (89 chars). Input schema is present with proper type and maxLength constraint. However, the tool's purpose is narrow (session renaming only), and the server lacks any discovery, resource, or prompt capabilities. The description could better explain WHEN to call this tool and what happens after. No error handling guidance, no output schema documented, and no indication of what the tool returns. The implementation appears minimal and lacks the composition patterns needed for a production agent toolkit.

• Add output schema to tool definition: document what fields are returned (e.g., session_id, new_title, updated_at, success boolean).
• Expand description to 100-150 chars: explain WHEN to call (e.g., 'Call after the first user message to set a descriptive session name for future reference') and what the tool returns.
• Add error handling guidance: 'If the title exceeds 80 characters, it will be truncated. If the session does not exist, returns an error with available session IDs.'
• Document idempotency: state whether renaming a session to the same title is a no-op or produces an updated_at timestamp.
• Consider adding complementary tools: get_session_info, list_sessions, delete_session to enable richer session management workflows.