Three tools with basic schemas and descriptions, but significant gaps in parameter documentation and output schema clarity. Tool names follow verb_noun convention (rag_query, rag_add_document, rag_list_documents), which is good. However, descriptions are minimal (34-72 chars, below the 194-char baseline), and critical parameter descriptions are missing or vague. The rag_add_document tool accepts a 'metadata' object with no schema definition. Output schemas are not documented anywhere in the source. Error handling and recovery guidance are absent. No tool annotations (readOnlyHint, destructiveHint, idempotentHint) despite clear risk profiles (WRITE vs READ_ONLY). This server lands in the 'fair' range, definitions exist but lack the depth and structure needed for reliable LLM tool selection.

• Document output schemas for all three tools. For rag_query, specify: {type: 'object', properties: {results: {type: 'array', items: {type: 'object', properties: {document_id: {type: 'string'}, content: {type: 'string'}, relevance_score: {type: 'number'}, metadata: {type: 'object'}}}, total_count: {type: 'integer'}}}.
• Expand tool descriptions to 150 - 250 chars. Include WHEN to call (e.g., 'Call rag_query to find documents matching a user question'), WHAT it returns (e.g., 'Returns up to n_results documents ranked by relevance'), and any prerequisites (e.g., 'Requires documents to be indexed via rag_add_document first').
• Define the 'metadata' parameter schema in rag_add_document. Specify allowed fields (source, author, tags, etc.) and types. If arbitrary fields are allowed, document that: {type: 'object', additionalProperties: {type: 'string'}}.
• Add tool annotations: readOnlyHint: true for rag_query and rag_list_documents; destructiveHint: true for rag_add_document. This signals to agents which tools are safe to retry and which require confirmation.
• Implement error handling with recovery guidance. Return structured errors: {error: 'service_unavailable', message: 'OpenSearch is unreachable', retry_after_seconds: 30, next_steps: ['Check OpenSearch cluster status', 'Retry in 30 seconds']}.