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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful non-annotation behavior: the response includes the URL of the full entry, and near-miss terms return the closest answers rather than failing. That fallback disclosure is the key trait an agent needs to interpret an approximate result.

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 with no wasted wording: the resource and scope come first, followed immediately by the illustrative terms and the return value. The fallback caveat is placed last where it belongs, and nothing is repeated from the schema or annotations.

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 single-parameter, read-only lookup with an output schema and full annotations, the description covers what is needed: what is looked up, example inputs, what comes back (definition plus URL), and how misses are handled. No material gap remains for an agent to call it correctly.

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?

There is a single required parameter with 100% schema description coverage, so the schema already explains that 'term' is a plain-words term string with an example. The description's example terms reinforce the expected granularity but add no syntax, format, or normalization guidance beyond the schema. Baseline 3 is appropriate when the schema carries the parameter burden.

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 gives a specific verb ('define') and resource ('Maps Agent glossary definition') and scopes it to Google Maps / Google Business Profile / local SEO terminology with concrete example terms. It is clear what the tool returns (a definition plus the URL of the full entry). It does not explicitly contrast itself with siblings like search_knowledge or get_article, so it stops short of a top score.

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 by the term-lookup framing: use this when you need a glossary definition of a local SEO term. The fallback clause ('falls back to the closest answers when the glossary has no entry') hints at limits, but there is no explicit guidance on when to prefer search_knowledge or get_article instead, and no stated prerequisites.

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