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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so 'Read-only.' in the description is pure repetition and earns no credit. The description does add behavioral value by enumerating the categories returned, but it says nothing about what happens for an unserved ZIP or any rate/coverage limits.

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?

Single front-loaded sentence covering purpose and scope, with no filler. The trailing 'Read-only.' sentence is wasted since the annotations already carry that hint, but the overall package is tight.

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 an output schema present, return shape need not be explained, and the one required parameter is documented in the schema. The description covers purpose and scope adequately; only the unserved-ZIP behavior is left implicit.

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% for the single 'zip' parameter, so the baseline is 3. The description adds only a mild constraint ('US') beyond the schema's pattern definition, which does not meaningfully extend parameter 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 specific verb and resource ('Check whether Detritus serves a US ZIP code') plus the full scope of what is listed (dumpster sizes, sanitation products, disposal materials, fencing, storage, water, power). This is unmistakably different from get_quote or make_service_request, so an agent can route without opening any schema.

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 rather than stated: an agent can infer this is the pre-flight availability check before quoting or requesting service, but the description never says when to prefer it over get_quote or make_service_request, nor states prerequisites or exclusions.

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