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

Annotations cover the safety profile (readOnly, openWorld, non-destructive), and the description adds genuinely new behavior: phone/website come back null when Google doesn't render them, service businesses usually carry both, and billing is one unit per result page fetched. Cost and data-availability disclosure beyond the annotations is exactly the value-add expected.

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?

Front-loads purpose and return shape, then tacks on location and billing caveats; every sentence carries information. Minor redundancy in restating 'Returns JSON' after already saying results come back as JSON.

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 no output schema, the description compensates by listing all returned fields and flagging which can be null. Combined with location and billing guidance, an agent has everything needed to call and interpret the tool.

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 the baseline is 3, but the description goes further by explaining the purpose of proxy_country plus gl/hl as a location-targeting mechanism rather than restating their type. It adds intent the schema alone doesn't convey.

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 ('Runs a Google Local (`tbm=lcl`) search for `keyword`') and enumerates the returned fields, which cleanly separates it from google_search and maps_place_details. An agent can tell this is the SERP-scraping local-results tool without opening the 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?

Gives clear operational context: local results are location-sensitive, so set proxy_country and optionally gl/hl to target a market, and keep max_results modest because of billing. It stops short of naming an alternative (e.g., maps_place_details) or stating when not to use this tool.

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