enter_pin

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

With no annotations provided, the description carries the full burden. It discloses the key behavioral trait: 'with a settle delay' between taps. It explains the internal logic for detecting native vs. canvas-drawn pads and the corresponding parameter strategies. While it does not specify return values or error conditions, the behavioral description is thorough for a tap-input tool.

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 moderately lengthy but every sentence contributes necessary information. It is well-structured: opening with the core purpose and usage trigger, then progressively detailing the pad-type logic and parameter modes. While not ultra-condense, the length is justified by the complexity of the two-path behavior.

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 tool's moderate complexity (4 parameters, two modes, no output schema), the description provides a complete workflow: identify pad type via describe_ui, determine parameter requirements, read bounds from screenshot if needed. It does not mention return values or failure modes, but covers the essential user/agent actions for correct invocation.

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% with well-documented parameters. The description adds significant value beyond the schema by explaining the conditional logic: when to use 'grid' vs 'coords' vs default, and how to obtain the bounding box or coordinates (e.g., 'read those bounds off a screenshot'). This contextual guidance helps the agent decide parameter values.

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 tool enters digits on a numeric PIN pad by tapping each key with a settle delay. It explicitly distinguishes from sibling 'input_text' by specifying when to use this tool ('Use when input_text does nothing because the pad renders its own key views'). The verb 'enter', resource 'digits on a numeric PIN pad', and method 'tapping each key' combine for a specific, actionable purpose.

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 when-to-use guidance: 'Use when input_text does nothing'. It also details how to choose between default, 'grid', and 'coords' parameter modes based on the pad type (native vs. canvas-drawn), instructing the agent to first run 'describe_ui' and potentially read bounds off a screenshot. This offers clear decision criteria and alternatives.

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