mcp-southwest

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description mentions it's used 'to proceed with booking,' implying a mutation step, but doesn't clarify if this is a reversible action, what permissions are required, whether it commits to a booking, or what happens after selection. For a tool with no annotations and apparent booking implications, this is a significant gap.

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 two concise sentences with zero waste. The first sentence states the purpose, and the second provides usage context, both front-loaded and efficiently worded.

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 no annotations, no output schema, and a tool that appears to be a mutation step in booking (implied by 'proceed with booking'), the description is minimally adequate. It covers purpose and workflow but lacks details on behavioral implications, error conditions, or what the tool returns, leaving gaps for an agent to understand the full context.

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 three parameters thoroughly. The description adds no additional parameter semantics beyond implying a connection to 'search_flights' results, which the schema's 'flightIndex' description already covers. Baseline 3 is appropriate when the 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 action ('Select a flight') and resource ('from search results'), with a specific purpose ('with a specific fare type'). It distinguishes from siblings by mentioning 'search_flights' as a prerequisite, but doesn't explicitly differentiate from other booking-related tools like 'checkout' or 'book_with_points'.

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 clear context by stating 'Use after search_flights to proceed with booking,' which indicates the prerequisite and workflow position. However, it doesn't specify when NOT to use this tool or name explicit alternatives among siblings like 'book_with_points' or 'checkout' for different booking scenarios.

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