AWS MCP Server

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

Annotations already provide excellent coverage (readOnlyHint, openWorldHint, idempotentHint, destructiveHint), so the bar is lower. The description adds minimal behavioral context - it implies region-based filtering but doesn't mention pagination (NextToken/MaxResults), dry-run capability, or filtering options. No contradiction with annotations exists.

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?

The description is a single, efficient sentence that front-loads the core functionality. Every word earns its place with no redundancy or unnecessary elaboration.

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?

For a read-only tool with good annotations but complex parameters and no output schema, the description is minimally adequate. It covers the basic action but lacks details about filtering capabilities, pagination behavior, response format, and differentiation from related tools.

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?

With 50% schema description coverage, the description should compensate but only mentions the 'region' parameter. It doesn't explain the complex SecurityGroupArgs object with filtering, pagination, and dry-run capabilities. The schema does heavy lifting for documented parameters, but undocumented aspects lack description support.

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?

The description clearly states the verb ('List') and resource ('security groups') with geographic scope ('in the given region'), making the purpose unambiguous. However, it doesn't explicitly differentiate from sibling tools like 'list-security-group-rules' or mention that this lists security group metadata rather than rules.

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?

The description provides no guidance on when to use this tool versus alternatives like 'list-security-group-rules' or 'create-security-group'. It doesn't mention prerequisites, typical use cases, or constraints beyond the region parameter.

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