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

The readOnlyHint annotation already establishes this is a safe read, and the description adds substantive value by naming the exact fields returned and the backing endpoint (GET /carriers). It does not discuss ordering, pagination, or empty-result behavior, but with annotations covering the safety profile this is solid context.

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?

Two compact sentences: the first front-loads verb, resource, and return fields; the second gives the follow-up handoff. Nothing is padded and no sentence repeats structured data verbatim.

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?

With no output schema, the description compensates by enumerating the returned fields, which is exactly what an agent needs to plan a downstream assignment. For a zero-parameter read tool with a readOnlyHint, nothing material 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?

The tool takes zero parameters, which is the baseline-4 case; the schema is empty and needs no explanation. The description correctly frames the tool as account-wide with no filtering arguments.

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 the account's carriers (drivers)') and enumerates the returned fields (id, name, phone, email, isOnShift, isActive, location). No sibling tool lists carriers, so an agent can distinguish it immediately from the order-oriented siblings.

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 sentence 'Use an id here with shipday_assign_order_to_carrier' gives clear workflow context: this is the discovery step that feeds carrier assignment. It stops short of explicit when-not guidance or naming other alternatives, so it falls just short of a 5.

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