MongoDB Tools provides 4 read-only tools with basic schemas and descriptions. All tools have input schemas with typed parameters and descriptions present. However, descriptions are generic and lack LLM-optimized guidance on when/why to use each tool. Output schemas are undocumented, query_collection and get_collection_stats return JSON strings rather than structured objects, forcing LLMs to parse unstructured text. Error handling is minimal (silent JSON error wrapping). No pagination support despite query_collection defaulting to limit=10. Tool names are clear (verb_noun pattern) but lack composition guidance. Security is adequate (read-only operations, no secrets exposed) but no permission gates or audit trails.

• Convert query_collection and get_collection_stats to return structured objects (dict/list) instead of JSON strings. FastMCP will serialize automatically. Document output schema: {documents: [{_id, ...fields}], total_count: int, returned: int}.
• Enhance descriptions with LLM-optimized guidance: 'Use query_collection to retrieve documents matching a filter. Call list_collections first to discover available collections. Returns up to 10 documents by default; use limit/skip for pagination.'
• Add pagination metadata to query_collection response: include total_count and a has_more flag so LLMs know whether to call again with skip=skip+limit.
• Implement structured error responses: {error: string, code: 'not_found'|'invalid_query'|'permission_denied', recovery: 'Try list_collections() to verify the collection exists'}.
• Add optional batch_query tool accepting array of queries to reduce sequential calls when agents need multiple lookups.