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

Annotations already flag readOnlyHint=false, idempotentHint=true, openWorldHint=true, and the description usefully reconciles the write behavior by disclosing that a changed page is stored as the new latest version. It also adds the auth prerequisite ("Needs a free SnoopScan key"), which annotations do not cover. It stops short of describing rate limits or storage retention/overwrite consequences beyond the latest-version statement.

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-loaded with the core purpose, then mechanism, then the includeDiff effect, then the auth requirement. Every sentence adds information and nothing is repeated from the schema or annotations.

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?

An output schema exists, so return-value detail is not required here. The description covers the action, the storage side effect, the first-check edge case, the includeDiff behavior, and the key requirement, which is enough for correct invocation; only the absence of sibling routing guidance leaves it just short of fully complete.

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 semantics. It does explain includeDiff (current content returned when the page changed) but gives no format, canonicalization, or validation guidance for url beyond the obvious, leaving one of two params only implicitly documented.

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 ("Check whether a page has changed") and explains the mechanism (fetches now, compares to latest stored version), which meaningfully separates it from plain scrape/fetch siblings. It never names an alternative tool (e.g. watchPages, checkMonitor) to complete the differentiation, so it lands at 4 rather than 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?

Gives contextual facts that guide use (first check of a URL reports it as new; includeDiff returns current content), which implies this is for one-off change detection. It never says when to prefer this over watchPages/checkMonitor or when not to use it, so the guidance is implicit rather than explicit.

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