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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true). The description adds real behavioral context beyond them: archived records are excluded, the call returns a single page, and paging is keyset-based via next_cursor/start_cursor. It stops short of describing rate limits or ordering defaults.

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?

Three dense sentences, front-loaded with purpose and scope, then filtering/routing, then transport and paging. No filler and nothing repeated from annotations or schema.

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 14-parameter, no-output-schema list tool, the description covers scope, filters, id sourcing, endpoint and paging, which is what an agent needs to call it correctly. Minor gaps remain around sort defaults and response envelope shape, but nothing essential is missing.

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 coverage is 100%, so the baseline is 3; the description earns an extra point by explaining the non-obvious provenance of three integer id filters (group_id, vehicle_type_id, vehicle_status_id) from named lookup tools and by restating the cursor/next_cursor contract. It does not cover sort_by/sort_direction interaction explicitly, which the schema already documents.

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?

States a specific verb and resource ('List vehicles') plus a key scope constraint ('not archived') and enumerates the fields returned (status, type, group, meter readings, VIN, plate). An agent can distinguish it from fleetio_get_vehicle and from sibling list_* tools without opening any schema.

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?

Explicitly names the filterable dimensions and routes the agent to the correct sibling tools for the required ids (fleetio_list_vehicle_statuses, fleetio_list_vehicle_types, fleetio_list_groups), which is genuine routing guidance. It does not state when NOT to use this tool (e.g. use fleetio_get_vehicle for a single known id), so it falls short of the 5 bar.

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