AWS MCP Server

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

Annotations indicate this is not read-only, idempotent, or destructive, but the description adds no behavioral context beyond the basic 'Create' action. It doesn't mention that this creates a new AWS resource, potential costs, time requirements, or that it might stop/reboot the source instance. With annotations covering only basic hints, the description fails to provide the behavioral transparency needed for a cloud resource creation tool.

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 concise at just three words. While this represents under-specification rather than ideal conciseness, it contains no wasted words and is front-loaded with the core action. Every word earns its place, even if more content is needed for completeness.

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?

For a complex AWS resource creation tool with 2 parameters (one being a complex nested object), no output schema, and annotations that only cover basic hints, the description is severely inadequate. It doesn't explain what an AMI is, the creation process implications, expected outputs, or error conditions. The description fails to provide the contextual completeness needed for proper tool invocation.

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 50%, with the 'region' parameter well-documented but 'AmiArgs' having nested objects with mixed documentation. The description adds no parameter information beyond what's in the schema. Since schema coverage is exactly 50%, this meets the baseline expectation where the description doesn't compensate for gaps but doesn't worsen them either.

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 'Create an AMI' is a tautology that restates the tool name without adding meaningful context. It doesn't specify what AMI stands for (Amazon Machine Image) or what the creation process entails. While it includes the verb 'Create' and resource 'AMI', it lacks the specificity needed to distinguish it from sibling tools like 'launch-ec2-instance' or 'list-amis'.

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. It doesn't mention prerequisites (e.g., needing a running instance), when this operation is appropriate, or what alternatives exist among the many sibling tools. For a complex AWS operation, this absence of context is a significant gap.

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