add_anim_float_curve

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

Annotations cover idempotent and destructive hints, but the description adds real context beyond them: the idempotency semantics (existing curve kept, keys replaced; identical keys yield changed=false and saved=false with nothing written), that it runs in one undo step then saves the package, and error behavior (missing sequence is an error; failed save gives success=false with save_error).

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?

Front-loaded with the core action, then idempotency, error, and sibling routing, all in a dense but fluff-free paragraph with a compact Returns line. Every sentence carries information, though the single long sentence is dense enough to be slightly hard to scan.

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?

With no output schema, the description supplies the full return field list, mutation/save semantics, idempotency behavior, and error cases. An agent has everything needed to call it correctly and interpret the result.

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, but the description adds semantics the schema omits: keys become linear keys with auto tangents, and num_keys reflects keys sent. Minimal gain over schema for curve_name/anim_sequence_path, but the interpolation behavior meaningfully enriches the keys parameter.

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+resource+scope: 'Add a float curve ... to a UAnimSequence through its data controller and set its keys from [time, value] pairs as linear keys with auto tangents.' It explicitly distinguishes itself from four named siblings (set_anim_curve_keys, add_anim_transform_curve, add_anim_curve_name, get_anim_curve_data), so an agent can route without opening schemas.

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 explicit routing by condition: 'Rekey: set_anim_curve_keys; transform curves: add_anim_transform_curve; a skeleton-only name: add_anim_curve_name; read back: get_anim_curve_data.' It also states when the tool is a no-op (curve already holds exactly those keys).

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