capture_ui

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

The description adds useful context beyond annotations: it states the return contents (node IDs, bounds, artifact hashes), explains that one owned temporary device XML file is used and deleted, and warns about partial semantics for some rendering technologies. This clarifies the destructive annotation rather than contradicting it.

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 three tightly written sentences: purpose first, then return and side effects, then limitation. Every sentence adds useful information with no wasted text.

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 description covers return contents, temporary file lifecycle, and rendering limitations, which are helpful for a complex device-capture tool. However, it omits parameter guidance and sibling differentiation, leaving notable gaps for correct invocation in this toolset.

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 only 33%, with serial and package undocumented in the schema, and the description does not mention any parameter meaning beyond 'Android device'. It does not compensate for the low coverage.

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: capturing Android screen, focus, and UIAutomator hierarchy into a snapshot. It is clear what the tool does, but it does not explicitly distinguish itself from siblings such as capture_adb_screen or read_ui_snapshot.

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?

There is no explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. The note that Compose/WebView/custom rendering may expose only partial semantics is a limitation, not usage routing.

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