AWS FinOps 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 of behavioral disclosure. It mentions AWS authentication parameters (profile_name, role_arn, etc.) which hints at credential requirements, but doesn't specify permissions needed, rate limits, error conditions, or whether this is a read-only operation. The description doesn't contradict annotations since none exist, but provides only basic operational context.

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 with clear sections for purpose, arguments, and returns. Every sentence adds value, though the parameter explanations could be slightly more concise. The front-loaded purpose statement is effective, and there's no redundant information.

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 moderate complexity (7 parameters, cost analysis functionality) and the presence of an output schema (which handles return value documentation), the description is reasonably complete. It covers all parameters thoroughly and states the return type. However, it lacks information about typical use cases, error handling, and performance characteristics that would be helpful for an AI agent.

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 excellent parameter semantics despite 0% schema description coverage. It clearly explains each of the 7 parameters, including format requirements (YYYY-MM-DD), optional status, default values for date parameters, and the purpose of each authentication parameter. This fully compensates for the lack of schema 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 tool's purpose with a specific verb ('Get'), resource ('cost breakdown by AWS region'), and scope ('for the specified period'). It distinguishes itself from sibling tools like 'get_cost_by_service' and 'get_cost_by_region_and_service' by focusing exclusively on regional breakdown.

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 like 'get_cost_by_service' or 'get_daily_cost_trend'. It mentions the period parameter but doesn't explain typical use cases, prerequisites, or limitations compared to other cost analysis tools in the sibling list.

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