adb_screen

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

With no annotations, the description carries the full burden. It discloses behavioral details like keyguard verification and PIN entry sequence. It lacks error handling or failure outcomes, but the core behavior is well explained.

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 concise with two main sentences and one detailed paragraph for PIN. It is front-loaded with the primary purpose. The structure is logical, though the detailed PIN entry sequence could be part of the parameter description, but overall it is well-organized.

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 core functionality but lacks information about return values or error scenarios. With no output schema and no annotations, some behavioral context (e.g., what happens on failure) is missing, making it somewhat incomplete.

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 100%, and the description adds meaning: it explains action enum values in plain language and provides additional context for the 'pin' parameter, specifying when it is used and its format.

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 tool's purpose: 'Control screen state: wake, sleep, toggle, lock, or unlock.' It lists specific actions and distinguishes from siblings like adb_screen_state by focusing on state manipulation rather than querying.

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 context for unlock behavior, including PIN entry and keyguard verification. However, it does not explicitly state when to avoid this tool (e.g., for checking screen state use adb_screen_state), but the given guidance is adequate.

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