mcp-southwest

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states what the tool returns (flights with fare options and pricing) but doesn't mention important behavioral traits like whether this is a read-only operation, if it requires authentication, rate limits, pagination, error conditions, or what happens with invalid parameters. For a search tool with 7 parameters, this leaves significant gaps.

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 perfectly concise - two sentences that efficiently convey the core functionality and return value. Every word earns its place with no redundancy or unnecessary elaboration. It's front-loaded with the primary purpose immediately clear.

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?

For a search tool with 7 parameters and no output schema, the description is adequate but incomplete. It covers the basic purpose and return format but lacks behavioral context (authentication, errors, limits) and doesn't explain the relationship between fare options mentioned and the fareType parameter. Without annotations or output schema, the agent has insufficient information about the full operation.

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 100%, so the schema already documents all 7 parameters thoroughly with descriptions, formats, enums, and requirements. The description adds minimal value beyond what's in the schema - it mentions fare options (Wanna Get Away, Anytime, Business Select) which aren't in the schema, but doesn't explain how these relate to the 'fareType' parameter. Baseline 3 is appropriate when schema does the heavy lifting.

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 ('Search for available Southwest Airlines flights'), identifies the resource ('between two airports'), and distinguishes from siblings by specifying it returns flights with fare options and pricing. This differentiates it from tools like 'get_fares' or 'get_flight_details' which likely retrieve specific fare/flight data rather than performing a search.

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 prerequisites, when to choose this over 'get_fares' or 'select_flight', or any constraints like availability windows. The agent must infer usage from the tool name and description alone.

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