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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. On top of that the description discloses the return shape (town page URL, county, county hub URL) despite there being no output schema, and notes that booking happens by phone with a vetted local operator. It does not say what is returned when a town is NOT covered, which is the one real 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 tight sentences, with the core purpose and return values front-loaded. The trailing booking-by-phone sentence is slightly tangential but earns some credit as workflow context.

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 one-parameter read-only lookup with no output schema, the description covers input form, outputs and the downstream booking path. The missing piece is negative-result behavior (not covered), a minor but real omission.

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% and the single parameter's own description already explains 'A UK town name or Rent-a-Skip town slug' with examples. The description's 'by name or slug' repeats rather than extends that, so baseline 3 is correct.

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 (checks) plus resource (town coverage for Rent-a-Skip) and even enumerates the returned values: town page URL, county, and county hub URL. Siblings (get_skip_prices, recommend_skip_size, get_permit_info) cover entirely different concerns, so an agent can route here unambiguously.

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: an agent infers this is the coverage pre-check before booking. There is no explicit when-to-use or when-not-to-use statement, and no sibling is named as an alternative for adjacent questions (e.g. pricing or size).

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