Fill one field by ref

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 value semantics for checkbox ('true'/'false') and select (option value or visible text) plus the ref provenance. It does not, however, describe failure behavior, focus/event side effects, or what the call returns, leaving gaps for a mutation tool with zero annotation coverage.

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?

Front-loaded with the core action, then usage scoping, then value special-cases, then the alternative. Dense and mostly waste-free, though the div/<form> elaboration is slightly verbose relative to the essential routing information.

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 no annotations, so the description must stand alone; it covers when to use it, how to address the field, and value formatting. It stops short of explaining the result of a successful fill or error conditions, but is largely sufficient for invoking the tool correctly.

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 67%, so the schema documents ref and value but leaves tabId bare. The description adds real meaning to value by specifying how to pass checkbox and select values, and clarifies that ref originates from browser_capabilities, going beyond the schema's own text.

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 ('Set a single field to a value') and immediately scopes it by the ref origin. It names browser_invoke as the alternative when a typed tool exists, so an agent can distinguish it from siblings like browser_act or browser_click.

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?

Explicit when-to-use ('pages Deputy could not graft into a typed tool — apps that build a form out of divs, or inputs sitting outside any <form>') and explicit when-not-to-use ('When a typed tool exists, browser_invoke is better'). Nothing is left to inference.

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