form_input

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

The description adds context beyond the destructiveHint annotation by stating that the value is set 'directly through accessibility,' indicating programmatic assignment rather than keystroke simulation. It does not contradict the annotation and offers useful behavioral nuance.

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?

A single, tightly worded sentence that is front-loaded with the key verb and resource. Every word contributes meaning, with no redundant 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 mutation tool with a destructiveHint annotation, the description plus schema cover the essential call contract. The overwrite behavior is already stated in the schema's value description, so nothing critical 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?

Schema coverage is 100%, with 'ref' explained as 'Element ref' and 'value' detailing type-specific behavior (text replaces content, booleans for checkboxes/switches, numbers for sliders/spin buttons). The description restates 'value' at a high level but adds no parameter meaning beyond 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?

The description uses a specific verb ('set'), a specific resource ('form control's value'), and a mechanism ('through accessibility, without typing'). This clearly distinguishes it from sibling tools like read_screen or find, which observe rather than modify the UI.

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 phrase 'without typing' implies a contrast with keyboard simulation, but the description never names an alternative tool or states when to use this over it. Usage is implied rather than explicitly guided, and there are no exclusions or conditions provided.

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