Accessibility Invoke Action

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

The description adds context beyond annotations by stating the Accessibility permission requirement and the behavior of returning available action names on invalid action requests. It also clarifies the meaning of 'AXPress'. Given annotations already indicate readOnlyHint=false and destructiveHint=false, the description adds useful extra 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?

The description is two concise sentences, front-loaded with the primary action and resource. It includes necessary details (default behavior, discovery mechanism, permission) without any wasted words.

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 simple 2-parameter action tool with no output schema, the description is comprehensive: it covers purpose, default behavior, action discovery, and permission. It does not explicitly mention return values or failure modes, but these are not critical given the tool's simplicity and existing annotations.

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?

While schema descriptions cover both parameters (100% coverage), the description adds value by explaining the default action ('AXPress') and clarifying that 'elementHandle' comes from ax_snapshot or ax_find. This reinforces the schema hints and gives practical contextual meaning.

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 the tool performs an accessibility action on an element, with the default 'AXPress' (click/activate). It distinguishes itself from siblings like input_click by specifying 'accessibility action' and the discovery mechanism for available actions.

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 clear context: this is for accessibility actions, and the default 'AXPress' maps to a click/activate. It also tells users to request an invalid action to discover available actions, which serves as a usage hint. However, it does not explicitly contrast with alternatives like input_click or mention 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.