phone_type_text

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

Annotations already declare destructive/openWorld/non-idempotent, and the description adds a genuinely useful behavioral fact not present there: typing appends rather than replacing, and does not trigger submit. It leaves unexplained why destructiveHint is true despite 'no clearing', which is the one remaining gap.

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?

Two short sentences, zero filler, with the core action front-loaded and the constraint clause second. Nothing to trim.

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?

An output schema exists so return values need no explanation, and the ASCII/append/no-submit notes cover key behavior. But with 0% parameter coverage and no mention of device targeting, an agent lacks enough to call this reliably in a multi-device setup.

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 0% — neither the required 'text' parameter nor the 'serial' device selector is documented anywhere. 'Printable ASCII' hints at content constraints for text, but the description never mentions serial, the 2000-char limit, or that a null serial targets a default device.

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 verb (type) and target (printable ASCII into the focused field), which cleanly distinguishes it from phone_press_key and phone_tap. It doesn't explicitly name a sibling, but the operation is 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?

'Into the focused field' implies a focus step must precede it (e.g., phone_tap_element), and 'No automatic submit or clearing' sets expectations about what the tool will not do. However, it never states when to choose this over phone_press_key or how to handle the field not being focused.

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