ui-action

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

Annotations already indicate destructiveHint=true and readOnlyHint=false. The description adds the 'tap, input, scroll' actions, which align with mutability. However, it does not disclose other behavioral traits like side effects, auth needs, or error conditions beyond what annotations provide.

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: a single sentence with no redundancy. It front-loads the core functionality ('Interact with app UI: tap, input, scroll') and adds a key usage hint ('Use selector or coords').

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?

Despite 9 parameters, nested objects, and no output schema, the description is very brief. It lacks details on parameter combinations, defaults, error handling, return values, and behavioral context. The tool is complex, and the description is not sufficiently complete.

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?

With only 22% schema description coverage, the description should compensate but does not. It lists operations but provides no additional meaning for most parameters (e.g., selector, elementIndex, x/y) beyond the schema. Two parameters (amount, deviceSpace) have descriptions, but that is minimal compensation.

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's purpose: interacting with app UI via tap, input, and scroll actions. It uses specific verbs and resource reference, and the list of operations distinguishes it from sibling tools like ui-capture and ui-query.

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 usage for UI interactions but provides no explicit when-to-use or when-not-to-use guidelines, nor does it mention alternatives or prerequisites. The context is implied but not detailed.

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