Cels

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

Annotations already flag destructiveHint=true and readOnlyHint=false; the description builds on that by explaining the state effects of 'move' and 'link' and clarifying that 'set' modifies position/opacity. No contradiction with the annotations; the added semantics go beyond the structured hints.

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?

Two tight sentences: the definition and op list come first, then focused detail on the non-obvious move and link operations. No filler, no repetition of schema content.

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 9-op, 12-parameter tool, the description covers the core concept and the most confusing workflows, while an output schema exists so return values need no explanation. Minor ambiguity remains around 'clear' vs 'delete' and 'copy', but the essential guidance is present.

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 approximately 50%, so the description is expected to help clarify undocumented parameters. It adds op-level context (position/opacity for 'set', frames for 'link', between-frames movement for 'move'), but leaves dx/dy, toFrame/toLayer, and the parameter implications of 'clear'/'delete'/'copy' implied rather than stated. Adequate, not thorough.

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?

States a specific verb and a defined resource ('Manage cels — one layer's image on one frame') and enumerates the full operation set. The definition clearly distinguishes cels from sibling tools like layer or frame, and the move/ink examples clarify what the resource represents.

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 concrete when-to-use guidance for the two least obvious operations: 'move' for shifting a limb between frames without redrawing, and 'link' for sharing an image across frames to keep a static part in sync. It doesn't name excluded sibling tools explicitly, but the scenarios give an agent enough context to select the right cel operation.

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