AWS MCP Server

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

With no annotations, the description carries full burden and successfully discloses the non-destructive nature ('without deleting') and timeout behavior ('messages return to the queue quickly'). Could improve by describing empty queue behavior or return payload structure.

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, zero waste. Front-loaded with core action (receive/peek) and key distinction (no delete), followed by mechanism explanation (visibility timeout). Every word earns its place.

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?

Lacks description of return values (message content, receipt handles, etc.) despite having no output schema. However, adequately covers the operational behavior for a 5-parameter tool with complete schema documentation.

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 has 100% description coverage, establishing baseline 3. The description adds context linking 'short visibility timeout' to the peek behavior but doesn't add syntax, format details, or semantic meaning beyond the schema definitions.

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 provides a specific verb ('Receive (peek)') and resource ('messages from an SQS queue'), and distinguishes from siblings by explicitly stating 'without deleting them' and contrasting with consume/delete patterns implied by 'peek' terminology.

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?

Implies usage pattern ('peek' vs full consumption) by stating messages aren't deleted and return quickly, but lacks explicit 'when to use' guidance or named alternatives for actual message deletion/processing.

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