Open an extension options page in a tab

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

Annotations only supply readOnlyHint=false, so the description must carry the rest, and it does add value: it discloses where the URL comes from (live manifest) and that the call fails clearly when no options page exists. It does not say what the failure looks like or how the 'background' flag changes tab visibility/focus.

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, no filler, and the alternative pointer placed last where a routing hint belongs.

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?

No output schema, and the description compensates with the resolution rule and error behavior, which is enough for an agent to call it correctly. The only gap is the unstated effect of 'background' on tab focus, left entirely to the schema.

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 both parameters (id, background) are already documented; the description adds no meaning about the id format or what 'background' actually does to focus. Baseline 3 applies when the schema does the heavy lifting.

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 ('Open the options page of an extension in a new tab') and adds the resolution source (live manifest, options_ui.page or options_page), which distinguishes it from browser_extension_details and browser_open_extension_popup in the sibling list.

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 routes the agent to browser_extension_details when it only wants the URL without opening a tab, which is a real selection criterion. It does not mention the adjacent browser_open_extension_popup sibling or any preconditions (e.g. extension must be installed/enabled).

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