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

Annotations already declare readOnlyHint and openWorldHint, so the description is not obligated to establish safety. It adds genuinely useful non-schema behavior: the $2.50 USDC price on Base, x402 payment, and that failed calls are not charged — a material fact an agent must weigh before invoking.

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, zero filler, with scope front-loaded before the cost/payment caveat. Every clause carries information an agent needs before calling.

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?

Cost and scope are covered, and params are fully specified in the schema, but with no output schema the description never says what comes back — rankings, AI answer mentions, competitor presence, or how previousSnapshot changes the response. For a paid, nested-object tool that is a real gap.

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 every parameter including brand, domain, country, language and previousSnapshot is already documented. The description only restates the keyword cap ('up to 25'), adding no format or constraint detail beyond the schema.

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?

Names a specific verb and resource: a SERP plus AI-answer check across all AI engines, with a stated cap of 25 keywords. The 'deep'/25-keyword scale implicitly separates it from serp_ai_monitor and ai_visibility_quick, but it never names a sibling or states the axis of difference 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?

There is no guidance on when to pick this over serp_ai_monitor, ai_visibility, ai_visibility_deep or ai_visibility_quick. The keyword cap hints at 'use this for larger keyword sets' but no condition, prerequisite, or exclusion is stated.

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