AWS FinOps MCP Server

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

No annotations are provided, so the description must cover behavioral traits. It mentions authentication parameters (profile_name, role_arn, access_key, etc.) which hints at credential handling, but does not disclose rate limits, permissions required, or whether this is a read-only operation. The description adds some context but lacks depth on operational constraints.

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 a clear purpose statement followed by parameter details and return value. It is appropriately sized for a tool with 7 parameters, though the parameter list is lengthy. Every sentence earns its place by providing essential information without redundancy.

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 7 parameters with 0% schema coverage and no annotations, the description does a good job explaining inputs and outputs. It specifies the return type ('Dictionary with cost breakdown by service'), and the output schema exists, so detailed return value explanation is not needed. However, it could improve by mentioning authentication requirements or data freshness.

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 0%, so the description fully compensates by providing detailed semantics for all 7 parameters, including formats (YYYY-MM-DD), defaults, and optional status. This adds significant value beyond the bare schema, clarifying usage and reducing ambiguity for the agent.

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 specific verb ('Get') and resource ('cost breakdown by AWS service'), and it distinguishes from siblings like 'get_cost_by_region' or 'get_daily_cost_trend' by specifying the breakdown dimension (by service). The title is null, so the description carries the full burden and does so effectively.

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 cost analysis by service within a date range, but it does not explicitly state when to use this tool versus alternatives like 'get_cost_by_region' or 'generate_cost_allocation_report'. No exclusions or prerequisites are mentioned, leaving the agent to infer context from the purpose alone.

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