add_anim_notify_state

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

Beyond the annotations (which only mark this as a non-idempotent, non-destructive write), the description discloses that the notify track is auto-created, that the sequence is saved, that unknown classes are refused, that repeated calls accumulate events, and that a failed save surfaces as success=false with saved=false and save_error. This is exactly the mutation/side-effect context an agent needs and is not present in the structured fields.

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 purpose and constraints are front-loaded and the tool is efficiently sized. The return values are stated twice (inline "Returns start_time, duration and success" and again as a full Returns block), a minor redundancy, but otherwise every sentence carries weight.

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?

There is no output schema, so the description carries the burden of describing returns and it does so fully (the field list plus failure semantics). Mutation behavior, save side effects, and error handling are all covered, leaving nothing an agent needs to invoke it correctly.

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 baseline is 3, but the description adds meaning: it clarifies that notify_state_name must resolve to a known class ("unknown classes are refused") and confirms start_time/duration are the timing inputs. This reinforces the schema rather than merely repeating it.

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 states a specific verb (Add) and resource (a UAnimNotifyState instance on a UAnimSequence notify track), including scope details like the track being created when missing. It explicitly distinguishes itself from the sibling add_anim_notify ("For instant notifies use add_anim_notify"), so an agent can route correctly without opening either schema.

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?

It gives a clear conditional routing rule to the alternative tool ("For instant notifies use add_anim_notify") and warns that each call adds another event rather than replacing. It stops short of a full when-to-use/when-not matrix, but the key sibling differentiation is explicit.

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