AWS MCP Server

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

No annotations provided, so the description must carry full disclosure burden. It fails to disclose what data is returned (key metadata, policy, grants, rotation status), required IAM permissions (kms:DescribeKey), or that this is a 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 description is extremely brief (4 words), but constitutes under-specification rather than purposeful conciseness. It wastes no words, yet fails to front-load any actionable guidance or behavioral context.

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?

Without annotations or output schema, the description leaves critical gaps: it omits what key attributes are returned (key usage, deletion status, origin, etc.), security implications, and how to interpret results.

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 with clear documentation for profile, region, and key_id. The description adds no semantic clarification beyond the schema, but baseline 3 is warranted per rules for high schema coverage.

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 'Describe a KMS key' is tautological, simply converting the tool name aws_kms_describe_key into sentence form. While it identifies the resource (KMS key), it does not distinguish from sibling tools like aws_kms_list_keys or aws_kms_list_aliases, nor does it explain what 'describe' entails.

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 provided on when to use this vs list operations (aws_kms_list_keys) or when profile/region overrides are necessary. No mention of permission requirements or that the key_id can be an alias, ARN, or ID.

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