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. It valuably discloses returned data (DNS names and state) but omits safety profile (read-only), pagination behavior, or filtering behavior implied by optional array parameters.

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 sentence, zero waste. Front-loaded with action verb and resource, followed by key output fields. 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?

Given well-documented schema and no output schema, the description adequately covers the tool's purpose and return value highlights. Minor gap: lacks explicit indication that this is a safe read operation or filtering capabilities notes.

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?

Input schema has 100% description coverage (profile, region, ARNs, names), establishing baseline 3. The description does not add parameter semantics beyond what the schema provides, nor does it need to given the comprehensive schema documentation.

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 uses specific verb 'List' with specific resource types (ALB, NLB, Gateway Load Balancers) and distinguishes from sibling tools like describe_listeners and describe_target_groups by clearly stating it operates on Load Balancers themselves.

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 implies usage by specifying the exact resource type (distinguishing from listeners/target groups siblings), but provides no explicit when-to-use guidance, prerequisites, or alternative tool recommendations.

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