AWS MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It partially compensates by specifying what data fields are returned (domain names, origins, status) since no output schema exists. However, it omits pagination behavior, rate limiting considerations, and confirmation that this is a safe read-only operation.

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 single sentence is efficiently structured with the action first ('List'), followed by resource and return value details. No redundancy or waste is present.

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?

Given the simple operation (list distributions) and lack of output schema, the description reasonably covers the essential return value semantics. However, it could improve by noting that results may be paginated (implied by max_items parameter) or that the operation returns all distributions across the account/profile.

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?

The schema has 100% description coverage for all three parameters (profile, region, max_items). The tool description mentions no parameters at all, relying entirely on the schema documentation. With complete schema coverage, the baseline score of 3 is appropriate.

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 action ('List'), resource ('CloudFront distributions'), and return scope ('domain names, origins, and status'). However, it does not explicitly distinguish from sibling 'aws_cloudfront_get_distribution' (single-item retrieval) or clarify when to use listing versus getting a specific distribution.

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 'aws_cloudfront_get_distribution'. It does not mention that all parameters are optional or provide criteria for when filtering by profile/region is necessary.

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