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

No annotations are provided, so the description carries the behavioral burden. It discloses the return of a trip ID and the free-tier limit, but it does not explicitly state that this is a mutating operation, any required authentication, or potential side effects. The description is not misleading, but it under-discloses for a write operation without annotation support.

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 sentences, front-loaded with the core action and key fields, then the return ID, then the free-tier constraint. Every sentence earns its place with no filler, making it concise and well-structured.

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 complexity (9 params, 7 required) and no output schema, the description covers the core purpose, return value, and a key constraint (free tier). The schema covers parameter details, and the description does not need to explain those. It is complete enough for an agent to call the tool correctly, though it could mention the rejection of future dates (already in schema) or error behavior, but those are minor 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?

Schema description coverage is 89%, so the schema already documents most parameters well. The description reiterates the field names but does not add new meaning beyond what the schema provides (e.g., it doesn't explain the note or jurisdiction fields, but those are covered in the schema). With high coverage, the baseline of 3 is appropriate.

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 ('Log one drive in the mileage log') and enumerates the key fields (date, from, to, distance, purpose, category). It distinguishes this tool from siblings by its verb and resource focus—logging versus listing, removing, or exporting trips. The return of a TR-YYYY-NNNN id is also mentioned, adding specificity.

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 gives clear context: it's for adding a trip to the mileage log, and it mentions the free-tier monthly limit, which is a usage constraint. However, it does not explicitly state when not to use it or mention alternatives like trip_remove or trip_list, so it lacks the exclusionary guidance needed for a 5.

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