Animate a sprite

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

With no annotations, the description carries the full burden. It usefully discloses the pixel-art constraint ("Integer/nearest-neighbour only — never blurred"), but omits that the timeline is replaced by default, what happens to an existing timeline, or any side effects and auth needs.

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?

Three tightly packed sentences with the core action front-loaded and a compact example at the end. The preset list partially duplicates the schema enum, which is mild waste but still aids quick scanning.

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 10-parameter mutation tool with no annotations and no output schema, the description covers the primary path adequately but leaves half the parameters and the replace/append semantics unaddressed. An agent could call it for the common case but would be guessing on seed and sourceFrame.

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 only 40%, so the description should compensate more than it does. The example clarifies preset, frames, durationMs, and amplitude, but seed, tags, easing, and sourceFrame receive no explanation in either the description or the schema.

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?

"Build a full animation timeline from the active frame" gives a specific verb and resource with clear scope. It does not distinguish the tool from close siblings such as sprite_tween, sprite_timing, or sprite_loop, so an agent must infer the boundary.

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?

Usage is implied through "Presets: idle_bob, walk_cycle..." and a concrete example invocation, which suggests when the tool applies. There is no explicit when-not-to-use statement and no routing to sprite_tween or sprite_loop for alternative animation workflows.

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