android_type_text

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

No annotations are provided, so the description carries the burden. It discloses a valuable behavioral trait – escaping spaces and special characters – which tells the agent it can safely pass arbitrary text. However, it does not mention failure modes (e.g., no focused field, invalid characters) or whether it waits for the field to be ready. This is partial but not silent, so a 3 is appropriate.

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 sentences, zero filler. The core purpose is in the first sentence, with the behavioral nuance (escaping) in the second. Every word earns its place, and it front-loads the most important information.

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 simple action tool with one required parameter and no output schema, the description covers the essential aspects: what it does, where it acts (focused field), and its escaping behavior. It could mention error conditions or whether it clears existing text, but these are minor for the scope. Overall, it gives an agent enough to call it correctly in most scenarios.

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% – both 'text' and 'deviceId' have clear descriptions. The description adds extra meaning for the 'text' parameter by explicitly stating that escaping is handled, which informs the agent that special characters are acceptable. This goes beyond the schema's simple 'Text string to type' and justifies a 4, slightly above the baseline 3.

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 states a specific verb ('Type text'), a specific resource ('currently focused Android input field'), and a key detail ('handles escaping for spaces and special characters'). This distinguishes it from sibling tools like android_tap or android_press_key, which serve different actions. The purpose is unambiguous and immediately clear.

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 implies usage (when you need to type into a focused field) but does not explicitly mention when not to use it or name alternatives. It lacks the directiveness of the top-tier example that names a sibling tool. However, the context of 'currently focused' and the sibling names (e.g., android_press_key) make the scenario understandable, so it earns a 3 rather than lower.

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