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

Annotations declare readOnlyHint=true, and the description reinforces this with a meaningful clarification: the call is a POST but "nothing is booked," which resolves the natural POST-is-a-write assumption. It also discloses what the response contains, though it omits auth/rate-limit or no-availability behavior.

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?

One compact sentence with an embedded list, followed by the read-only reassurance and the underlying endpoint. The purpose and return-shape are front-loaded with essentially no filler, though the trailing endpoint note is of marginal value to an agent.

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?

There is no output schema, so the description correctly compensates by spelling out what the quote returns (available services, fee, timing). The remaining gap is edge-case behavior when no service can deliver, which is minor for a read-only quote tool.

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 every parameter is already documented with a description and, for the time fields, a precise ISO 8601 pattern. The description adds no format or constraint detail beyond naming pickup and delivery addresses, so the baseline 3 applies.

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 (quote) and resource (third-party on-demand delivery availability) and enumerates the payload contents (services, fee, pickup/delivery times). It stops short of differentiating itself from close siblings like shipday_get_on_demand_estimate and shipday_get_on_demand_details, which an agent could easily confuse with this tool.

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?

"Before creating an order" gives a clear lifecycle position, implying usage over shipday_create_order. However, it never names or excludes the near-identical siblings (get_on_demand_estimate, get_on_demand_details), leaving the agent to infer which quoting tool to pick.

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