AWS MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so description carries full burden. It discloses return payload structure (engine, status, endpoint, size, storage) which helps, but omits safety classification (read-only), pagination behavior, rate limits, or error conditions. 'Describe' implies read-only but explicit confirmation would help.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with zero waste: first defines operation, second defines return payload. Perfectly front-loaded and appropriate length for complexity level.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Without output schema, description partially compensates by listing return fields. However, lacks operational context (pagination, max results, throttling) and doesn't clarify that omitting db_instance_identifier returns all instances. Adequate but incomplete for production use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, establishing baseline of 3. Description adds no specific parameter guidance beyond schema (e.g., no examples for filters format, no clarification on optional vs required behavior since all are optional).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States specific verb 'Describe' and resource 'RDS database instances', distinguishing from siblings like aws_docdb_describe_db_instances and aws_rds_describe_db_clusters. Mentions specific return fields (engine, status, endpoint, etc.) clarifying scope. Minor gap: could explicitly mention this retrieves metadata/configuration, not performance metrics.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use filters vs. db_instance_identifier parameter, or when to prefer this over aws_rds_describe_db_clusters. No mention of required AWS permissions or typical use cases (e.g., inventory vs. troubleshooting).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.