AWS FinOps MCP Server

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

No annotations are provided, so the description carries the full burden. It discloses the tool's read-only nature by implying it 'finds' unused AMIs without modifying them, but lacks details on permissions, rate limits, or error handling. The description adds some context but is incomplete for a tool with 8 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?

The description is well-structured and appropriately sized, with a purpose statement followed by 'Args' and 'Returns' sections. It avoids redundancy, though the parameter list is lengthy due to the high parameter count, which is necessary for clarity.

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 the tool's complexity (8 parameters, no annotations, but has an output schema), the description is mostly complete. It covers purpose, parameters, and return type, though it could improve by adding usage guidelines or behavioral details like authentication requirements.

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?

With 0% schema description coverage, the description fully compensates by listing all 8 parameters with clear semantics, including defaults and optionality (e.g., 'period: Minimum age in days for AMI to be considered unused (default: 90)'). It adds meaning beyond the bare schema, making parameters understandable.

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 clearly states the tool's purpose with a specific verb ('Find') and resource ('AMIs not used by any EC2 instances, ASGs, or Spot Fleet Requests'), distinguishing it from siblings like 'find_unused_cloudwatch_alarms' or 'find_unused_s3_buckets' by focusing on AMIs and their usage status.

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, such as other 'find_unused_' tools for different resources or cost analysis tools. It lacks explicit context, exclusions, or prerequisites, offering only the basic functionality.

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