Set attributes

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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=false). The description adds real behavior the annotations cannot convey: that all attribute paths are validated up front because Cavalry silently ignores writes to unknown paths, which also explains why skipValidation exists.

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?

Three short sentences, each load-bearing: scope and frame behavior first, then the validation rule, then the rotation tip. No filler and the most decision-relevant fact is front-loaded.

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 mutation tool with annotations covering safety and a fully documented schema, this is nearly complete. Remaining ambiguity is whether provided attributes merge with or replace existing values and what the call returns, but with no output schema and strong annotation coverage those are minor omissions.

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. The description still adds meaning beyond the schema by explaining the pre-write path check (the reason skipValidation exists) and by giving the rotation.z convention for 2D rotation, which the schema's example only shows as a bare value.

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 (set) and resource (attribute values on a layer), plus the crucial scope qualifier "at the current frame (does not create keyframes)" that separates it from cavalry_set_keyframes and from the read-side siblings cavalry_get_attributes/cavalry_list_attributes.

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 parenthetical "does not create keyframes" tells the agent when NOT to use this tool and implicitly routes animation writes to cavalry_set_keyframes, and "In 2D, rotate with rotation.z" gives a concrete usage rule. It stops short of naming the alternative tool explicitly or stating prerequisites.

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