add_animation

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

Annotations provide no safety cues (all false), so the description carries the burden. It discloses the prerequisite that an existing AnimationPlayer is required and points to create_animation_player otherwise. However, it does not mention side effects like overwriting animations with the same name, scene saving behavior, or error conditions, which would matter for a mutation 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?

Two concise sentences, front-loaded with the core action and target. The alternative pointer to create_animation_player is valuable and does not add fluff. No wordy or redundant 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?

Tool has 7 parameters with nested track/keyframe structures, and no output schema. The schema is thorough, and the description gives essential prerequisite context, but it lacks return/error behavior and detailed side-effect information. Minimally adequate for invocation, but not deeply complete.

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 the schema already documents all parameters. The description adds only high-level context (tracks, keyframes, existing node) already reflected in schema properties. Baseline 3 is appropriate since no extra parameter syntax or meaning is provided.

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?

Description uses a specific verb+resource: 'Add an animation with tracks and keyframes to an existing AnimationPlayer node.' It clearly differentiates from sibling 'create_animation_player' by focusing on adding to an existing node and mentioning the alternative.

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?

Explicitly states when to use this tool (on existing AnimationPlayer) and when not (to create the player itself) with direct alternative: 'To create the AnimationPlayer itself, use create_animation_player first.' This gives clear usage boundaries.

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