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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=true, idempotentHint=false), and the description adds real behavioral context: cost ($0.008 USDC per call via x402 or prepaid credits), free-trial availability, and the persistent token/ignoreNumbers semantics across calls. It does not state rate limits or failure behavior, but the payment and statefulness disclosures are meaningful additions.

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 the core capability and the sibling comparison, then adds pricing. Slightly redundant since the title already states $0.008, which the description repeats verbatim, but overall tight and well ordered.

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 an output schema present, return-format details are unnecessary, yet the description still characterizes the summary output (two sentences, significance vs noise). Payment, trial status, and stateful token behavior are all covered, leaving nothing an agent needs 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?

Schema coverage is 100%, so the baseline is 3; the description adds value by clarifying the token lifecycle ('send back the token from your last check') and the statefulness of ignoreNumbers being remembered in the token, beyond the per-parameter schema text.

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+resource (page change detection with an AI summary) and explicitly positions it against the sibling page-changes tool, spelling out the delta: the two-sentence summary of what changed and whether it is significant vs noise. An agent can distinguish this from page-changes without opening either 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?

Explains the token round-trip workflow ('send back the token from your last check') and the first-check vs subsequent-check pattern, which tells the agent how to use it. It implies the alternative (plain /page/changes) but does not explicitly say when to prefer this paid version over the free one, so it falls short of a full when/when-not statement.

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