gesture-pinch

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

No annotations are provided, so the description fully bears the burden of behavioral disclosure. It discloses auto-generation of interpolated frames at ~60fps, the direction mapping (startDistance > endDistance = pinch in), the angle parameter effect, the return value, and that failure occurs if the backend is unreachable.

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 efficiently structured: first sentence states the main action, then provides coordinate space clarification, direction mapping, typical values, performance details, angle explanation, usage guidance, return value, and failure condition—all in 8 sentences with no redundancy.

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 has 7 parameters, no output schema, and no annotations, the description covers all necessary behavioral aspects, parameter usage, return value, and error conditions, making it fully complete for an agent to select and invoke 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 description coverage is 100%, so baseline is 3. However, the description adds significant value beyond the schema by explaining normalized coordinates (0.0–1.0) and their meaning, providing typical values (0.2 and 0.6), and clarifying the relationship between startDistance and endDistance for zoom direction.

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 executes a pinch-to-zoom gesture, specifies the effect (change scale), and distinguishes from similar tools like gesture-tap and gesture-swipe by noting the same coordinate space. It also provides use cases (zoom on map, image, etc.).

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 explicitly says 'Use when you need to zoom in or out on a map, image, or zoomable view,' providing clear usage context. It does not explicitly state when not to use or compare to alternatives like gesture-custom, but the mention of distinct coordinate space and two-finger gesture helps differentiate.

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