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

Annotations already provide destructiveHint=true and idempotentHint=true, and the description adds critical behavior: invalid registrations are returned in invalid[], and it requires an Enterprise account key. This goes beyond the structured fields and discloses edge-case behavior and auth prerequisites.

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 description is a single concise sentence that front-loads the core action, then adds the key scoping and error-handling details. No wasted words; every clause contributes to understanding.

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 single-parameter tool with a full schema and output schema present, the description covers the action, scope, invalid input behavior, and auth requirement. Nothing an agent needs 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 description coverage is 100%, and the parameter 'registrations' is fully documented with format constraints (Brazilian registrations, hyphen/case flexibility, length, count limits). The tool description does not add extra parameter semantics beyond what the schema already states, so a baseline 3 is appropriate.

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 clearly states the action (remove registrations from the watch list) and explicitly scopes it ('WITHOUT touching the rest'), distinguishing it from batch operations or list management tools. It also mentions invalid registration handling, which further clarifies its purpose.

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 description implies usage context (selective removal from watch list) and notes the account key requirement, but it does not explicitly mention alternatives like jt_watch_set for bulk replacement or when not to use this tool. Still, the context is clear enough for an agent to route correctly.

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