Type Text

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

The description mentions support for special characters and Unicode, which is useful behavioral context. However, it does not disclose any potential side effects (e.g., what happens if no input field is focused, or if the text is too long). Given no annotations are provided, the description carries the burden, and it partially fulfills 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 two sentences long, with no wasted words. It front-loads the core action and adds necessary prerequisite in the second sentence.

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?

Given the tool has only 2 parameters with full schema coverage and no output schema, the description provides the essential prerequisite and feature support. It is mostly complete for a simple input action, though it could mention error behavior or limitations.

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?

Input schema covers both parameters with descriptions ('Device serial ID' and 'Text to type on the device'), achieving 100% coverage. The description does not add meaningful semantics beyond what the schema already provides, so baseline 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 'Type text' and the resource 'currently focused input field', distinguishing it from sibling tools like 'press_key' (types keys rather than text) and 'smart_type' (likely types intelligently). It is specific and unambiguous.

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 explicitly instructs the agent to make sure an input field is focused first (tap on it), which is a crucial prerequisite. This provides clear guidance on when to use this tool and the necessary precondition.

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