Accessibility Set Value

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

The description goes beyond the annotations by disclosing the fallback behavior (focus/select-all/type), the verification step (read-back comparison), and the permission requirement. This adds valuable context beyond the readOnlyHint and destructiveHint flags, with no contradictions.

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?

Two sentences carry all essential information without redundancy. The description is front-loaded with the primary action and then details fallback and reporting, making efficient use of every word.

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 mutation tool with no output schema, the description adequately explains what happens (direct set or fallback), what the return value indicates (read-back success), and the required permission. This is complete for a tool of this complexity.

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?

The schema already fully describes both parameters (elementHandle and value) with clear descriptions. The tool description adds no additional parameter-specific detail, so the baseline of 3 applies given the 100% schema coverage.

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 clearly states a specific action (set an element's AXValue), the resource (the element), and a fallback mechanism. It distinguishes itself from sibling tools like ax_invoke by focusing on value setting.

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 implies when to use the tool (when you need to set an element's value) and notes a prerequisite (Accessibility permission), but it does not explicitly contrast with alternatives like input_type or ax_invoke, nor does it state when not to use it.

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