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

No annotations are provided, so the description carries the full burden. It explicitly discloses that the tool refuses when nothing is focused, explains the rationale (device accepts keystrokes regardless), and describes the force option as an override. This goes beyond basic expectations and is highly transparent.

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 dense but not overly verbose. It front-loads the core purpose, then adds essential usage details and the refusal behavior. The explanation of the old behavior adds length but provides valuable context. Each sentence earns its place, though a slightly tighter version could be possible.

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 three parameters and no output schema, the description covers all necessary aspects: the action, prerequisites, special key handling, refusal behavior, force override, and session requirement. It is fully sufficient for an agent to call the tool correctly.

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 coverage is 100% with descriptions for all three parameters. The description adds meaningful context for 'text' (\n for Return/Go with an example) and 'force' (rare, for surfaces where active element isn't reported), going beyond the schema's brief descriptions. This justifies a score above 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 clearly states the action ('Type text into the FOCUSED field on an iOS device') with a specific verb and resource. It also includes a prerequisite ('tap a text field first') that distinguishes it from other input tools, and the iOS-specific naming helps differentiate from session_send_keys or device_type.

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?

Provides clear usage instructions: tap the field first, use \n for Return/Go, and force:true as a rare override. It also notes the requirement of an active iOS automation session. While it doesn't explicitly name alternative tools, the usage context and prerequisites are well articulated, earning a 4.

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