AWS MCP Server

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

No annotations provided, so description carries full burden. States 'List' implying read-only safety but fails to disclose pagination/truncation behavior (critical for AWS list operations with Limit parameter), rate limits, or return structure. Missing behavioral traits despite having zero annotation coverage.

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?

Single efficient sentence of 9 words. Front-loaded with action verb. No redundant filler. However, breverity borders on under-specification given lack of output schema and annotations.

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?

Inadequate for AWS API complexity with no output schema. Missing crucial ListUsers API behaviors: pagination token handling (absent from schema), truncation indicators, filter syntax limitations, or return value structure. Should provide context for how 'limit' interacts with result sets.

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%, providing full parameter documentation. Description mentions 'optional filter' which restates schema constraint (filter not in required array) but adds no additional syntax guidance or format details beyond schema examples.

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?

Specific verb 'List' with clear resource 'users in a Cognito user pool'. Distinguishes from sibling 'list_user_pools' by specifying users (not pools) and implying the requires pool context. However, lacks explicit differentiation from other Cognito siblings like list_groups.

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 versus alternatives, prerequisites (e.g., obtaining user_pool_id), or when filtering is preferable. Description is purely functional declaration without workflow context.

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