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

Going well beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false), the description discloses the rescan cadence (~once a day), the private watch_id and RSS feed return values, optional webhook posting, that no account is needed, and a 90-day expiry. These are exactly the behavioral facts an agent cannot derive from structured fields.

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 primary purpose and then dense with lifecycle and return-value facts; every clause carries information. The monitoring list is long but purposeful, so it is only slightly verbose rather than wasteful.

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 values need not be re-explained, and the description still covers what the agent needs: no auth required, what changes are tracked, watch lifetime, and which sibling tools manage the resulting watch. Nothing essential is missing for correct invocation.

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 schema already documents both url and webhook_url fully. The description reinforces webhook behavior but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

The description states a specific verb and resource ('Start watching a page') and enumerates exactly what is monitored (page down/redirect, new noindex, AI crawler blocking, canonical/title changes, score drops, errors). It is clearly a create-a-watch operation, distinct from siblings like get_watch and unwatch.

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?

It names the companion tools and their purpose ('Use get_watch to read the history and unwatch to stop'), giving the agent a clear lifecycle workflow. It does not state explicit when-not-to-use conditions or contrasts against adjacent monitoring siblings, so it falls short of a 5.

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