Close an open extension popup

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

Goes well beyond the single readOnlyHint=false annotation by disclosing the actual mechanism: there is no Firefox close-popup API, so the panel element is merely hidden. That is important context, since the popup may persist in the DOM rather than truly being destroyed, and it notes the tool reports what it found and closed.

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, front-loaded with the action and its target, followed by the implementation caveat and the result behavior. No sentence is filler.

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 zero-parameter, non-destructive cleanup tool with no output schema, the description covers purpose, mechanism, the API limitation, and a hint at the return value. Nothing an agent needs in order to call 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly avoids inventing parameters.

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 (close) and resource (the tool-panel popup opened by browser_open_extension_popup), and explicitly names the sibling it pairs with. An agent can distinguish this from browser_close_tab or browser_quit without opening any schema.

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 pairing with browser_open_extension_popup makes the when-to-use condition clear: close what that tool opened. It does not state a when-not-to-use case or what happens if no popup is open, but the implied context is unambiguous.

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