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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds value beyond them: the API-key requirement and both accepted header names, plus the plan-gated nature of certain features. It does not mention rate limits or error behavior, so it stops short of 5.

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?

Four sentences, each earning its place: purpose, input modes, return shape, auth. Front-loaded with the core action and 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 13-parameter tool with no output schema, the description covers purpose, input modes, auth, and return granularity by jurisdiction. It omits error/failure behavior and pagination, which is a minor gap given the schema already documents every parameter.

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 the schema descriptions already carry the precision tradeoffs (door-level vs. ZIP-overlap, plan requirements, historical lookback). The description largely restates address-vs-lat/lng and adds little syntax or format detail the schema lacks, 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+resource ('Look up sales and use tax rates') with the geographic scope (US or Canadian location). An agent can immediately tell this apart from the only sibling, get_account_metrics.

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?

Explicitly routes between the two input modes: full street address for door-level accuracy vs. a lat/lng pair for a point lookup, matching the schema's anyOf. It gives clear context but does not state exclusions or when to fall back to the less-precise postalcode option (that guidance lives only in the schema).

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