status

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

With no annotations, the description carries the full behavioral burden, and it does disclose two useful traits: it is user-visible ('shown on an on-page panel') and non-blocking ('Instant, never blocks'). It does not say whether successive calls replace or queue the previous status, whether it returns anything, or any rate/usage limits.

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, front-loaded with what the tool is before the timing and behavior guidance. Every sentence carries distinct information; no 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 two-parameter, no-output-schema UI tool, the description covers purpose, when to call, latency profile, and content of the argument. The remaining gap is undefined repeat-call behavior (replace vs. append), which matters for an on-page panel that a multi-step task will write to repeatedly.

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% so the baseline is 3, and the description adds real semantics on top: 'One short sentence' constrains the content of the required text parameter, and 'Use the user's language' is a localization instruction absent from the schema. The spaceId/tabId pairing is left to the schema.

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 concrete purpose: emitting one short sentence shown on an on-page panel to tell the user what the agent is about to do. It is a progress-narration tool, clearly not a browser action, which implicitly separates it from siblings like click/navigate. It does not name a sibling or explicitly contrast with e.g. 'ask', so it falls short of a 5.

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 explicit call timing: 'Call before a multi-step task and whenever the plan changes.' That is a clear when-to-use rule. It stops short of stating when NOT to call (e.g. for trivial single-step work or after a task completes), and names no alternative tool.

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