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

With no annotations provided, the description carries the full burden, and it does so substantially. It discloses that group layers only receive pivotX/pivotY (not width/height/rotation), that keyframe tracks override static values at every frame, that scale/opacity writes over animated properties are refused, and that clear_animation:true replaces the animation. It does not narrate the response shape or permissions, but no output schema exists and the mutation behavior is well covered.

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 opening sentence front-loads the core action and field list, then narrows scope by layer kind before addressing animation edge cases. The prose is dense but purposeful; the schema already documents each parameter, so the description wisely focuses on cross-field behavior. Slightly long for a first sentence, but every clause earns its place.

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?

The description robustly covers the tool's edge cases, group behavior, animation interactions, and coordinate-space pitfall for a 10-parameter mutation tool with no annotations and no output schema. It does not explain the return value or error shape, but with no output schema declared and schema descriptions covering all parameters, the missing bits are minor.

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%, so the baseline is 3 and the description need not compensate. It adds some useful framing beyond the schema, such as 'writes ... on image.<id>, video.<id>, and shapes.<id>' and the note about group layers, but most parameter semantics (units, clamping, coordinate spaces) already live in the schema. The description does not significantly deepen parameter understanding beyond the schema's own descriptions.

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 names a specific verb ('Set') and a precise resource ('a layer's static base transform') and enumerates exactly which fields are written for which layer kinds. It explicitly contrasts with add_keyframe, so an agent can distinguish move_layer from its sibling animation tools.

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 clearly states when to use move_layer: to set static/un-animated defaults, and explicitly says to use add_keyframe for group rotation and for animating properties. It also explains the refusal behavior when a keyframe track exists and instructs passing clear_animation:true to replace animation. The in-schema coordinate guidance ('inside a group it is the group's space') clarifies the context for using x/y.

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