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 that the tool returns a 'Dictionary with daily cost trend and statistics,' which adds some context about the output format. However, it lacks critical behavioral details: it doesn't specify if this is a read-only operation, potential rate limits, authentication requirements beyond parameter listing, error conditions, or data freshness. For a tool with AWS cost data access, this is a significant gap in transparency.

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 appropriately sized and front-loaded: the first sentence states the core purpose, followed by structured 'Args' and 'Returns' sections. There's minimal waste, with each part serving a clear function. However, the parameter explanations are very brief and could be more informative, slightly reducing efficiency.

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 complexity (6 parameters, no annotations, but has an output schema), the description is moderately complete. It covers the purpose and parameters adequately, and the output schema likely details the return structure, reducing the need for description here. However, it lacks behavioral context (e.g., safety, performance) and usage guidelines, which are important for a tool interacting with AWS cost data. The presence of an output schema helps but doesn't fully compensate for these gaps.

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 adds substantial meaning beyond the input schema, which has 0% schema description coverage. It explicitly lists all 6 parameters with brief explanations (e.g., 'Number of days to look back' for 'days', 'AWS profile name' for 'profile_name'), clarifying their purposes and optionality. This compensates well for the lack of schema descriptions, though it doesn't detail parameter interactions or constraints (e.g., mutual exclusivity of credential options).

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: 'Get daily cost trend for the specified number of days.' It specifies the verb ('Get'), resource ('daily cost trend'), and scope ('specified number of days'). However, it doesn't explicitly differentiate from sibling tools like 'get_cost_by_region' or 'generate_cost_allocation_report', which also retrieve cost-related data but with different scopes or formats.

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 sibling tools like 'get_cost_by_service' or 'generate_cost_allocation_report', nor does it specify prerequisites, such as AWS Cost Explorer permissions or typical use cases (e.g., monitoring spending trends). The only implied context is the need for AWS credentials, but no explicit usage scenarios are provided.

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