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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behaviour: booking happens by phone and this tool collects no personal details, which tells the agent it is informational only and cannot complete a reservation. It does not state what happens with an unknown postcode or size, which is the main remaining gap.

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 sentences, front-loaded with the core answer set (number, hours, cut-off, preparation checklist) before the conditional price/permit behaviour. The parenthetical list is dense but each item is a real thing the caller needs. Slightly list-heavy rather than wasteful.

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 carries the return burden and does so by enumerating what the caller gets back: phone number and hours, cut-off, preparation checklist, guide price and permit applicability. Both parameters are optional and the description makes clear the tool still works without them. Only the edge-case behaviour for partial or unrecognised inputs is unaddressed.

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% and both parameters are documented, including the size enum labels, so the baseline of 3 applies. The description does add the effect of passing them ('give a postcode and a size for the guide price and whether a council road permit applies'), which is useful causal context the schema does not convey. It does not explain the behaviour when only one of the two optional parameters is supplied.

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 names a specific resource and outcome: booking instructions for Crestway Skip Hire (phone number, hours, next-day cut-off, what to prepare), plus an optional guide price and council permit check keyed on postcode and size. An agent can tell this is the 'how do I book' tool rather than a price or size lookup. It stops short of naming or distinguishing any sibling, so the boundary with skip_prices is left to inference.

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 implied: use it to get booking logistics, and supply postcode plus size if you also want a guide price and permit answer. There is no explicit when-to-use versus when-not, and no routing to skip_prices or skip_sizes even though the guide-price behaviour clearly overlaps. The 'Booking is by phone' line hints at the boundary (this tool does not book), but that is left implicit.

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