AWS FinOps MCP Server

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

With no annotations provided, the description carries full burden but only states what the tool does, not how it behaves. It lacks critical behavioral details: authentication requirements (multiple credential options but no guidance), rate limits, whether it performs read-only operations, what happens with large result sets, or error conditions.

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?

Well-structured with purpose statement followed by organized parameter and return sections. Every sentence adds value, though the credential parameter explanations could be more concise by grouping similar options.

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 8 parameters with 0% schema coverage and no annotations, the description does excellent work documenting parameters and stating the return type. However, it lacks behavioral context needed for a tool with multiple authentication options and potential AWS API interactions. The output schema existence reduces but doesn't eliminate this gap.

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?

The description provides comprehensive parameter documentation beyond the 0% schema coverage, explaining all 8 parameters with clear semantics: region_name, period (with default and unit), max_results (with default), and all credential options. This fully compensates for the schema's lack of descriptions.

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 specific action ('Find Lambda functions with no invocations') and resource ('Lambda functions'), with precise scope ('in the specified period'). It distinguishes from siblings like 'find_underutilized_lambda_functions' by focusing on zero usage rather than low usage.

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 for identifying unused functions within a time window, but provides no explicit guidance on when to use this vs. alternatives like 'find_underutilized_lambda_functions' or other cost optimization tools. No prerequisites or exclusions are mentioned.

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