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

Annotations already establish readOnly, idempotent, openWorld and non-destructive, and the description goes meaningfully beyond them: it discloses the price ($0.25 USDC), the accepted payment rails (Base or Solana), the required X-PAYMENT header and Bearer credit-key alternative, the 20-result cap, and the data-hygiene rules (role emails only, personal-looking emails dropped, opt-outs honoured). It stops short of stating rate limits or what a failed/unpaid response looks like.

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?

The purpose is front-loaded before the payment parenthetical, so an agent gets the gist in the first clause. It is a single dense sentence with nested parentheses, which is slightly heavy but every clause (payment, auth, exclusions) carries operational weight.

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 carries the return-value burden and does so adequately by naming the returned fields (role emails, business phones, social links). Payment and auth prerequisites are fully covered. Minor gaps remain: no statement of pagination/empty-result behavior and no resolution of the q/query alias duplication.

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 already 80% and the schema itself documents q as 'Business type, e.g. dentists (alias: query)', gl, num's 1-20 default, and the location example. The description only restates the 'query and location' pairing and the 20 cap, so it adds little semantic value. It also leaves the q-vs-query alias relationship ambiguous when both are supplied.

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 and resource: 'Maps/places businesses for a query and location (up to 20)', then adds the differentiator that each result is enriched with contact details from the business website. That enrichment clause functionally separates it from the plain places_search sibling, though it never names that sibling explicitly.

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 context is implied rather than stated: you use this when you need leads with contact emails rather than raw place listings. The description spends its guidance budget on payment mechanics ('Paid via x402 ... or a prepaid credit key') and 'Not in the free trial', but never says when to prefer this over places_search or what happens on a zero-result query.

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