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

Annotations only declare readOnlyHint=false and openWorldHint=true, so the description carries real weight here and delivers: it discloses the returned monitor id, a manage token that is shown only once, feed/events URLs, and concrete free-plan limits (60-minute minimum interval, 3 active monitors, 30-day retention). It still omits auth requirements and what happens when a check fails.

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?

Three compact sentences, front-loaded with the action, then the return values, then the plan limits. Every clause carries information; the 'Free plan: ...' fragment is terse but readable and earns its place as quota context.

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 13-parameter, nested-object, no-output-schema tool, the description usefully covers the return shape and plan limits, but leaves most parameter behavior and the paid/x402 flow unexplained. An agent could invoke it with just url, but could not confidently use modes or webhooks from this text alone.

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?

With 13 parameters and only 62% schema description coverage, the description should compensate, but it explains none of them — no mention of mode, selector, jsonpath, fields, webhook_url, or paid. The single hint is indirect: the free-plan '60 minutes or slower' note maps to interval_minutes. That is far short of what 13 params at moderate coverage require.

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 — 'Create a monitor that checks a public page on a schedule and records changes' — which is unambiguous and clearly distinct from a one-shot extraction. It does not explicitly name extract_page or get_changes as siblings, so an agent must infer the recurring-vs-once distinction rather than being told.

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 scheduled/recording nature implies when this tool is appropriate versus extract_page, but no alternative is named and no when-not-to-use condition is given. The plan-tier constraints are stated, which is useful context, but they are quota facts rather than routing guidance.

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