input_text

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

With no annotations provided, the description fully bears the burden of behavioral disclosure. It discloses all key behaviors: the IME mechanism, the prerequisite focus requirement, the side effect of keyboard obstruction, the suggested mitigation, and the specific failure case (native PIN pads). No contradictions present.

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 3 sentences, front-loaded with the primary action, 135 characters per sentence average. Every sentence provides distinct value: primary action, prerequisite, and post-action guidance with alternative tool reference. Slightly longer than strictly necessary but no wasted words.

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 complexity of text input on mobile devices (IME vs native, keyboard obstruction), the description is complete. There is no output schema, but the side effects and failure modes are well documented. The description covers prerequisite, mechanism, side effect, mitigation, and the known exception case comprehensively.

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 100%, so baseline is 3. The description adds significant value beyond the schema: 'serial' is documented in the schema, but the description adds the 'via the IME' mechanism and keyboard dismissal context for 'text'. The description does not repeat the schema's parameter definitions verbatim but adds operational context that clarifies the intended usage of the 'text' parameter.

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 uses a specific verb ('type text') and identifies the target resource ('currently focused input field') with a clear mechanism ('via the IME'). It also explicitly distinguishes itself from the sibling tool 'enter_pin', which handles native PIN pads, preventing confusion.

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 explicit step-by-step guidance: tap the field first for focus, and dismiss the keyboard with press_key escape/back before tapping other buttons. It also explicitly states when NOT to use this tool (for native non-IME PIN pads) and directs to the alternative 'enter_pin'.

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