browser_fill_form

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

Annotations already indicate destructiveHint=true, readOnlyHint=false, openWorldHint=true, meaning it is a mutating operation. The description adds no behavioral context beyond that, such as whether it clears existing fields, requires element visibility, or scrolls. With annotations present, the description should still provide extra behavioral details but fails to do so.

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?

The description is extremely concise (3 words, 1 sentence). While it is front-loaded, it is too brief to be fully informative. It earns its place by stating the core purpose, but it lacks the detail expected for a tool with a complex input schema. Not wasteful, but under-specified.

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 complexity (array of objects with 5 fields, each with types and enums), the description is far too minimal. It does not explain how to prepare the form (e.g., obtain a snapshot), what happens if the fields are not found, or what the tool returns. There is no output schema, so the description should compensate. It does not.

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%; each parameter (target, name, type, value) has a clear description in the schema. The tool description 'Fill multiple form fields' does not add any meaning beyond what the schema already provides. The baseline is 3 for high coverage, and the description does not improve or degrade parameter understanding.

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?

The description 'Fill multiple form fields' clearly states the action (fill) and the resource (form fields). The name 'browser_fill_form' and the input schema (array of fields) reinforce that it handles multiple fields at once. It distinguishes from siblings like 'browser_type' (single field typing) and 'browser_select_option', though it does not explicitly call out alternatives.

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 description provides no guidance on when to use this tool vs alternatives (e.g., browser_type, browser_select_option), no prerequisites (e.g., page snapshot required), and no when-not-to-use conditions. It is a single sentence with no usage context.

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