Triggers a specific secondary accessibility action on a chosen UI element in a desktop app. Use it to activate options that standard clicks do not expose.
Invoke a secondary accessibility action exposed by an element
| Name | Required | Description | Default |
|---|---|---|---|
| app | Yes | App name, full app path, or unambiguous bundle identifier | |
| action | Yes | Secondary accessibility action name | |
| element_index | Yes | Element identifier |
Changes observed during successful MCP inspections.
v0.5.0Input schema / $defsAdded value: +{
+ "__schema0": {
+ "anyOf": [
+ {
+ "type": "string"
+ },
+ {
+ "type": "number"
+ },
+ {
+ "type": "boolean"
+ },
+ {
+ "type": "null"
+ },
+ {
+ "items": {
+ "$ref": "#/$defs/__schema0"
+ },
+ "type": "array"
+ },
+ {
+ "additionalProperties": {
+ "$ref": "#/$defs/__schema0"
+ },
+ "propertyNames": {
+ "type": "string"
+ },
+ "type": "object"
+ }
+ ]
+ }
+}Input schema / additionalPropertiesPrevious value: -falseNew value: +{
+ "$ref": "#/$defs/__schema0"
+}v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide all false hints, so the description itself must communicate side effects and behavior. It only restates that an action is invoked and does not explain whether the action modifies state, can fail, is reversible, or has side effects. For a tool that calls out to application accessibility behavior, this is a meaningful gap.
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 an efficient single sentence with no filler. It front-loads the verb and object, which is appropriate for this tool.
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?
This is an action-invoking tool with no output schema, no examples, no explanation of what kinds of actions can be supplied, and no guidance on where the element identifier comes from. An agent could invoke the correct function name, but it would be under-specified when selecting valid values and predicting outcomes.
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 input schema covers all three parameters with descriptions, so the bar for the description is lower. However, the schema descriptions are terse, and the tool description adds no further meaning to 'action' or 'element_index.' Baseline 3 is appropriate because the schema is complete but shallow.
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 states a specific verb and resource: 'Invoke a secondary accessibility action exposed by an element.' This is reasonably clear, though it relies on the jargon 'secondary accessibility action' and does not explicitly contrast with sibling tools such as click, set_value, or type_text.
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 gives no guidance about when to use this tool versus alternatives. It does not say that standard interactions should go through click or that this is for custom/extra actions, leaving the agent to infer the appropriate scenario from the name and sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.