get_app_state

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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable behavioral context beyond those annotations by revealing that it may start an app use session if needed and that it is a required precursor to all other app interactions. There is no contradiction: 'if needed' is consistent with idempotentHint.

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 with no filler. The primary behavior is front-loaded, and the critical call-cadence rule is delivered as a clear imperative in the final sentence.

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?

With one documented parameter, strong annotations, explicit return values, and a clear usage cadence, the description gives an agent everything needed to select and invoke the tool correctly. Even without an output schema, it names the two expected outputs: a screenshot and an accessibility tree.

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 description coverage is 100%, with the app parameter documented as 'App name, full app path, or unambiguous bundle identifier.' The description does not need to explain parameter semantics further, so the baseline score of 3 applies.

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 and resource: 'get the state of the app's key window and return a screenshot and accessibility tree.' It distinguishes this tool from sibling action tools like type_text and click, and from computer_use_status, by clearly framing it as a state-reading and observation tool.

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 explicit sequencing and frequency guidance: 'This must be called once per assistant turn before interacting with the app.' This tells the agent exactly when to use the tool relative to the other app-interaction tools, which is strong usage guidance.

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