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

Goes well beyond the annotations: it describes the return behavior ('Returns the app's new state with the next snapshotId, so no extra snapshot is needed'), the failure mode ('If the window changed, nothing is done and the error comes with the current state to retry from'), a success caveat, and required permissions.

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?

Front-loaded with the core action, and the follow-on sentences on return/error/permission behavior each carry real information. Dense but not padded.

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 no output schema, the description does the heavy lifting by explaining the returned snapshot state, the retry-on-error path, and permissions. The main remaining gap is elementId semantics, which is left to the bare schema.

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 coverage is 50%; deviceId and workSessionId are documented in the schema, while snapshotId and elementId are not. The description adds meaning for snapshotId ('latest app_snapshot', retry-from state) but says nothing about elementId beyond the schema, so it only partially compensates.

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 ('Open the context menu of an element of the latest app_snapshot') and anchors it with a concrete analogy ('as a right-click does'). This distinguishes it clearly from siblings like app_press or app_select.

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?

It implies the workflow context (must operate on an element from the latest app_snapshot) but never states when to choose this over app_press, app_select, or app_increment. Usage is inferable but not explicit, with no exclusions.

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