double_click

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

No annotations are provided, so the description carries full behavioral burden. It discloses the allowlist precondition, the error-and-no-op behavior on failure, and the side effect (word selection). It doesn't cover return values or coordinate validation, but for a simple click tool this is largely sufficient.

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?

Two sentences, zero waste, front-loaded with the action and immediately followed by side effect and precondition. All information is present and efficiently ordered.

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?

Given the tool's simplicity, 2 parameters, no output schema, and no annotations, the description covers the essential action, side effect, and critical precondition. It is nearly complete, missing only minor details like coordinate source (though noted in schema) or failure error format.

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 baseline is 3. The description adds no parameter details beyond what the schema provides; it only implies a coordinate is required. The schema already documents both parameters thoroughly.

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 action (double-click) and its location (given coordinates), and adds the concrete effect 'Selects a word in most text editors', which distinguishes it from left_click and triple_click siblings.

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?

Explicitly states the precondition: 'The frontmost application must be in the session allowlist at the time of this call', and describes the failure mode. This tells the agent when the tool will succeed versus error, which is crucial for routing between it and request_access.

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