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

Annotations only declare readOnlyHint=false, which is consistent with a tool that persists snapshots, so no contradiction. The description adds real behavioral context the annotations lack: the first call records a baseline and reports no change, and snapshots are kept per page and tag. It stops short of covering rate limits, snapshot retention, or diff format.

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 purpose, then statefulness, then the tag convention, then alternatives — each sentence carries distinct information with no filler. The alternative-routing sentence is compactly packed at the end where it belongs.

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 still describes the return well enough to act on (a diff, with the first call reporting no change). Minor gaps remain around the shape of the diff and any error or rate-limit behavior, but nothing critical for invoking the tool correctly is missing.

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 baseline would be 3, but the description adds operational meaning beyond the schema: it tells the agent to pass its own agent id as tag and explains the consequence (two watchers not consuming each other's changes). That is guidance the schema text only partially conveys.

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 ("Check whether a public web page has changed since the last time this was called for it, and get the diff") and explicitly names the sibling tools it is not (read_web_page, web_search). An agent can distinguish it from the large sibling list immediately.

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 an explicit when-to-use profile ("Use for watching one page over time: a company's team or leadership page, a pricing page, a careers page") and routes to alternatives with conditions ("For the contents of a page use read_web_page; for the open web use web_search"). Nothing is left to inference.

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