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

Annotations already declare readOnly, closed-world, non-destructive, so the safety profile is covered; the description adds real value by disclosing the negative-case return ("nearest served city when the answer is no"). It does not describe the positive-case return shape, leaving a small 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?

Three short sentences, front-loaded with the question being answered, then the caveat, then the return behavior. No filler.

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 lookup with annotations covering safety and no output schema, the description covers purpose, the negative-case result, and inter-tool routing. Only the yes-case return value 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 coverage is 100%, so baseline is 3; the description earns one more by widening the accepted input to ZIP codes, which the schema's example ("Morgan Hill" / "San Jose, CA") does not convey. The slight tension between "city or ZIP" and the schema's city-name framing is a minor weakness.

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 question it answers ("do you serve <city or ZIP>?") scoped to ORS Clean's named service regions, which is far more than restating the name. It also distinguishes itself from the sibling request_quote by noting that tool performs its own service-area check.

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?

Gives an explicit exclusion ("Not required before request_quote") plus the reason, preventing an unnecessary chained call. The alternative is named by name, so the agent knows where else service-area logic lives.

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