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

With no annotations, the description carries the full load and does substantial work: it discloses a persistent side effect (a durable baseline is written), the differential return shape (only added/removed URLs), a per-call price of $0.01 USDC on Base, the x402 payment location in params._meta, and the exact HTTP endpoint. Gaps remain: it does not say what a first call returns when no baseline exists, how long a baseline persists, or what happens if the sitemap fetch fails after payment.

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?

Purpose is front-loaded in the first clause, followed by the payment and transport facts in a compact second sentence. No filler or repetition. The payment boilerplate is dense but necessary for a paid x402 endpoint.

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 stateful, paid, three-parameter tool with no annotations and no output schema, the description covers statefulness, cost, and the differential result but omits parameter meaning and baseline lifecycle details. An agent can understand what the tool does and how to pay, but not confidently how to size 'max' or 'submaps' or what the first call yields.

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 0% and all three parameters (max, url, submaps) are undocumented in the schema. The description only indirectly hints at 'url' via 'a site's sitemap URL'; it says nothing about what 'max' caps or what 'submaps' controls (sub-sitemap traversal depth? count?). Half-documented parameters carry real ambiguity for an agent that must supply them.

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: a sitemap inventory change monitor that stores a baseline then returns only added/removed URLs. That is far more precise than a bare name restatement, and the 'sitemap' qualifier implicitly separates it from generic diff siblings such as chgwatch__diff or pageaudit__sitemap. It stops short of naming those alternatives explicitly, which keeps it from a 5.

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?

The two-phase pattern ('stores ... as a durable baseline, then later returns only added/removed URLs') implies when the tool is appropriate and conveys the call sequencing an agent must follow. There is no explicit when-not guidance and no named alternative for generic (non-sitemap) change detection or for multi-URL comparison. Usage is inferable but not directed.

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