Add keyframes

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

Annotations already declare a non-read-only, non-idempotent, non-destructive mutation, so the safety profile is covered. The description adds channel-level unit semantics but says nothing about the operation's key behavioral risk: whether adding tracks merges with or overwrites existing bone/channel tracks, and whether duplicate keyframe times are rejected or overwritten. With annotations doing the safety work, a 3 is appropriate, though the merge/replace ambiguity is a real gap for a non-idempotent 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?

A single front-loaded sentence with high information density and no filler; the parenthetical unit notes earn their place by disambiguating channel values. It is arguably too terse for a mutation tool, but there is no wasted wording to cut.

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 three-parameter nested mutation with no output schema, the description covers purpose and value units adequately. What is missing is pipeline context (the target animation must exist, likely created via add_animation) and the append-versus-overwrite behavior, both of which an agent needs before invoking a non-idempotent write.

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 33%, so the description must carry weight — and it does give genuinely useful semantics that the schema omits: rotation in degrees, position in units, scale as factors. However, it leaves the `tracks` array structure, the `animation` reference parameter, and the three-level interpolation precedence (keyframe vs track vs top-level default) entirely to the schema, which only partially documents them.

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 resource ("Adds keyframe tracks to an animation") and immediately scopes the payload to per-bone and per-channel data. The per-channel unit notes (degrees, units, factors) further pin down what is being added. It stops short of differentiating itself from siblings like add_animation or add_bones, leaving the agent to infer the pipeline order.

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 phrase "to an animation" implies the animation must already exist, but there is no explicit prerequisite statement, no pointer to add_animation for creating the target, and no guidance on when to use this versus other mutation tools. There are also no exclusions — e.g., whether tracks are appended or replace existing tracks for the same bone/channel.

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