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

The description adds substantial context beyond annotations: new paid watches include 7 days of polling, a $0.005 paid poll renews 7 days, polling keeps the watch alive, beta watches remain free, and no API key is required. This is valuable for a non-read-only tool (readOnlyHint=false) with a monetary side effect, although the repeated billing sentences dilute the signal.

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?

The first sentence is well front-loaded, but the pricing/payment rules are repeated three times with near-identical wording ('New paid watches include 7 days...', 'Free through the watch's included polling window...', 'After that window, one $0.005 paid poll renews...'). Much of the text does not earn its place.

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?

There is no output schema, so the description should explain what comes back; it only says the response carries a new cursor and never describes the alert payload. It does cover the complex payment/liveness model and auth (no API key), but it omits the actual response shape and task-selection guidance.

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 100%, so the schema already explains watch_id, key, and since. The description restates the since cursor concept and mentions the new cursor in the response, but adds no syntax or format detail beyond the schema baseline.

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 opening sentence, 'What is new since your last run,' implies incremental polling of an existing watch, and the title supplies the missing verb/resource. However, the description itself never explicitly says it polls a watch for new alerts, and it does not distinguish this from siblings like check_now or poll_trial.

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 gives a mechanical instruction to pass since={last seq you saw}, but does not state when to use this tool versus check_now, poll_trial, or the watch_* variants. The only contextual guidance is billing-related, not task-selection guidance.

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