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

The description explicitly warns that the entire price history is deleted and cannot be recovered, and that re-adding starts empty – which goes well beyond the annotation's destructiveHint=true. It also states that a non-matching key is refused, a failure condition an agent needs to know. This aligns with annotations, and no contradiction exists.

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 short sentences, each earning its place: action+parameters, irreversibility consequence, and error condition. The purpose is front-loaded in the first sentence. No filler or repetition of structured fields.

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 simple two-parameter destructive tool with annotations already present, the description covers the essential call semantics, the lasting side effect, and the failure mode. It does not describe the return value, but with no output schema and a straightforward removal, that is not required. The description is complete enough for an agent to invoke correctly.

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 description is not required to document parameter syntax. It does add the semantic that id and URL are alternative means of identifying the watch, and that a key must match an existing watch. However, the schema already conveys the 'if you do not have the id' relationship, so the description adds marginal value.

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 opens with 'Call this tool to stop tracking one item, by watch id or URL,' which clearly states the verb, the resource, and the two acceptable keys. This distinguishes it from siblings like watch_add and watch_list, and the title aligns with the description. No ambiguity remains about what the tool does.

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 tells the agent when to call it: when you want to stop tracking an item, and it offers two input methods (id or URL). It does not explicitly name alternatives or exclusions, but the context of 'stop tracking' is sufficiently clear. The error note about non-matching keys is helpful for understanding when a call will fail.

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