Device info

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

No annotations exist, so the description carries the full burden; it does convey that the data is passively reported by WebDriverAgent, which implies a read with no side effects. It says nothing about whether values are cached/snapshot-at-session-start or live, or what happens if no session exists — gaps that matter for a session-scoped read.

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?

A single compact sentence with the core resource front-loaded and the concrete payload fields appended. Nothing redundant and nothing 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?

For a no-parameter, no-annotation, no-output-schema tool, the description is nearly sufficient — it names the returned fields and the reporting agent. It falls short only on session preconditions and whether repeated calls return fresh values.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The enumerated return fields (model, iOS version, screen) add useful framing without being required.

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?

States a specific resource — session capabilities plus device info — and enumerates concrete fields (model, iOS version, screen) and the source (WebDriverAgent). It isn't confused with any sibling (screenshot, page_source, current_app), though it never explicitly names what separates it from current_app, which also reports state.

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?

No statement of when to call this versus alternatives, no prerequisites (e.g., that a session must be active), and no exclusion criteria. The agent has to infer usage purely from the tool name.

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