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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds real behavioral context beyond that: it names the underlying GET /service_tasks call, states that only one page is returned, and explains the keyset paging mechanism. It still omits default page contents/ordering nuances, but this is solid added value.

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 short sentences, front-loaded with the tool's identity and purpose, with no filler. It is efficient, though the endpoint path is arguably redundant for an agent that never invokes raw HTTP.

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 simple read-only list endpoint with no output schema, the description conveys purpose, pagination behavior, and scope sufficiently. The main omissions are return-field detail and explicit sibling routing, which are minor given annotations and the 100%-covered schema.

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 all five parameters (filter, sort, per_page, cursor, direction) are already documented in the schema. The description's only parameter-related note, mapping next_cursor to start_cursor, largely restates what the schema's start_cursor field says. Baseline 3 is appropriate when the schema carries the semantics.

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 clear verb+resource ('Lookup: the service tasks ... and their ids') with concrete examples (Oil Change, Tire Rotation) that clarify what a service task is versus a service entry. It does not explicitly differentiate from siblings like fleetio_list_service_entries, but the resource is specific enough that an agent can distinguish a catalog lookup from transaction listings.

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?

Usage is only implied by the word 'Lookup' and the endpoint path; there is no statement of when to prefer this tool over fleetio_list_service_entries or the work-order/service-reminder siblings. It does give practical pagination handling guidance (pass next_cursor as start_cursor), which is a genuine usage instruction.

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