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

Goes well beyond the destructiveHint annotation by disclosing the cascade ('with all its domains'), the protected blacklist exemption, the required user confirmation step, and a plan-level gating requirement. These are exactly the facts an agent needs before triggering an irreversible operation.

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?

Four short sentences with no filler, and the destructive scope is stated first. Slightly choppy sentence fragments, but nothing that wastes the agent's attention.

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 single-parameter destructive tool with no output schema, the description covers consequences, exclusions, confirmation duty, and eligibility. Nothing needed to invoke it 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% and the single listId parameter is already documented as coming from listWatchlists, so the description correctly adds nothing new. 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?

States a specific verb and resource ('Delete one of your watchlists') and adds scope detail that the name alone doesn't convey: the domains go with it. It does not explicitly contrast with deleteSignalSet, but the resource nouns are distinct enough that an agent can separate them.

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 two concrete operating conditions: ask the user to confirm first, and paid plans only. It lacks an explicit statement of when to delete versus rename or remove domains individually, which keeps it 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.