Input text

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

Despite no annotations, the description discloses key behaviors: it types into the currently focused field, and if a locator (id/text/resource_id) is provided, it taps that field before typing. This gives the agent expected sequencing without overpromising. No contradictions with annotations.

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 short sentences, front-loaded with the primary action. Every word contributes value, with no fluff or repetition of schema details.

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 tool with 8 parameters, this description is concise but covers the essential behavior and the optional targeting mechanism. The schema provides rich descriptions for per_char_delay and observe, so the description doesn't need to repeat them. It adequately frames the tool's role.

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?

The description adds meaning to the schema by grouping id/text/resource_id as alternative targeting options and explaining that providing one will trigger a tap first. This clarifies their purpose beyond the individual schema descriptions, which otherwise treat them as generic strings.

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 action 'Type text into the focused field' and mentions the optional targeting behavior. This distinguishes it from sibling tools like tap and press_key, which are concerned with tapping or key presses, not text entry.

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 gives clear context that this tool is for typing text, with an optional step to target a field first. It does not explicitly mention alternatives or exclusions, but the purpose is unambiguous, making it easy for an agent to decide when to use it.

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