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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: this is a paid x402 endpoint costing $0.08 USDC on Base and requiring an X-PAYMENT header. It does not say what happens on missing or invalid payment (error vs. challenge), which is the remaining 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?

Two short sentences with zero filler; the capability and scale are front-loaded and the cost and payment mechanism follow immediately.

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 paid, no-output-schema tool, the description covers cost and the payment mechanism, which are the highest-risk unknowns. It leaves out the meaning of 'num' and any indication of the response shape (e.g. per-query result grouping), so an agent can invoke it but not fully predict it.

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 0%, so the description must carry parameter meaning and it largely does not. It maps loosely to 'queries' via the 25-search cap, but the 'num' parameter is never mentioned and its meaning (results per query, 1-20) is left for the agent to guess.

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 names a specific verb and resource ('Up to 25 Google web searches in one call'), which lets an agent distinguish it from single-query siblings like web_search or news_search. It stops short of explicitly naming the alternative for single queries, so it is clear but not fully differentiated.

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?

Batching is implied by 'Up to 25 ... in one call' and the price signals this is a metered operation, giving an agent enough to infer when to prefer it over a single search. There is no explicit when-not guidance, no note that a single query should go to web_search, and no prerequisites beyond the payment header.

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