create_blend_space

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

Annotations already declare idempotentHint=true, destructiveHint=false and readOnlyHint=false, but the description goes further: it specifies the exact idempotent-hit semantics (asset returned unchanged, already_existed=true, saved=false, nothing saved) and the failure path (success=false with save_error). It does not mention permission or skeleton-compatibility requirements, so not a full 5.

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 create statement is front-loaded, followed by idempotency and failure semantics, then the return fields. The Returns block is long but justified because there is no output schema. Slightly more verbose than strictly necessary but every line carries information.

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 inline Returns field list is the right compensation, and the failure/idempotency behavior is spelled out. Coverage is slightly incomplete on how skeleton_path interacts with axis configuration, but otherwise the agent has what it needs to call this 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 schema already documents all seven parameters including their defaults. The description adds no parameter syntax or constraints beyond what the schema provides, making the baseline 3 appropriate.

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 and resource ('Create and save a UBlendSpace (or UBlendSpace1D) asset under /Game') and clarifies the 1D/2D duality. It does not, however, distinguish itself from close siblings such as scaffold_blend_space_2d or remove_blend_space, so an agent must infer the boundary.

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?

There is no explicit when-to-use guidance and no mention of alternatives, prerequisites, or when not to call this tool. The idempotency note is behavioral rather than a usage rule, so the agent gets no routing help among the many blend-space siblings.

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