Server has 5 tools with basic schemas and descriptions, but significant gaps in parameter documentation and output schema clarity. Tool names follow verb_noun convention (list_, get_, set_) which is good. However, most parameter descriptions are minimal (1-2 words), and output schemas are not documented anywhere in the provided source. No error handling guidance visible. The session_index.py code shows robust internal validation but this is not exposed to the MCP interface. Descriptions range 34-89 chars (within baseline 34-392), but parameter annotations are sparse or missing entirely.

• Document output schemas for all tools. Example: list_codex_sessions should return {sessions: [{id: string, title: string, model: string, cwd: string}], total: number}. This enables agents to chain calls and extract required fields.
• Expand parameter descriptions with format/range constraints. Change 'Unix timestamp to fetch updates since' to 'Unix timestamp (seconds since epoch, e.g. 1704067200 for 2024-01-01). Must be <= current time.'
• Add error recovery hints to tool descriptions. Example: 'If session not found, call list_codex_sessions() to see available sessions.' This guides agents on retry strategy.
• Add tool annotations: mark set_codex_toolbar_injection with destructiveHint=true (modifies system state) and idempotentHint=true (repeated calls with same params produce same result).
• Document pagination behavior for get_codex_trajectory. Specify: 'Returns up to maxRecords results. If more exist, response includes next_cursor for fetching subsequent batches.'