android_ui_dump

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states that the tool returns a structured, compact list of visible and interactive elements, including text, resource IDs, and screen bounds. This tells the agent what to expect and implies it is read-only (no side effects mentioned). It doesn't mention prerequisites like accessibility service permission or failure modes, but for a 'dump' operation, the core behavior is transparent. Slight gap: does not say whether it blocks or returns immediately, but that is minor given the nature of the tool.

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 clear sentences, starting with the verb 'Dump' and the resource. It front-loads the core action, then specifies output details in a single compact second sentence. No extraneous words or repetition—every phrase adds value.

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?

The tool is simple (one optional param, no output schema), and the description covers the essential information an agent needs: what it returns and limits the results to visible and interactive elements. This is adequate for an agent to decide whether to call it and what to expect. It could be more explicit about whether the list is flat or hierarchical, and whether it includes scrollable/element hierarchy beyond visible ones, but the given detail is sufficient for typical use.

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 schema has only one optional parameter (deviceId) and its description coverage is 100%, so the schema already tells the agent what the parameter does. The tool description does not add any extra semantics about deviceId (e.g., default behavior, format, or when it's needed). Since coverage is complete, the description doesn't need to compensate, and a baseline of 3 is appropriate.

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 verb 'dump' and the resource 'Android screen UI hierarchy', and specifies the output: a structured list of visible, interactive elements with text, resource IDs, and bounds. This distinguishes it from siblings like android_find_element (which searches for specific elements) and android_click_element (which interacts), so an agent can tell them apart.

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 a use case (inspecting the current UI hierarchy) but does not explicitly state when to prefer this over alternatives, nor does it mention exclusion criteria. For example, it doesn't say 'use android_find_element to locate a single element' or 'use when you need an overview of all visible elements vs. screenshot'. The context is clear but guidance is implicit rather than explicit.

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