set_shape_key

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

With no annotations present, the description carries the burden and does real work: it explains that value normally ranges 0.0-1.0 but is bounded by the slider range, that negative slider_min lets a 'smile' key also frown, that mute disables without destroying the stored value, and that an empty vertex_group clears the limit. It stops short of stating error behavior when object or key is missing, or whether the change is undoable.

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 lead sentence is front-loaded and each Args line earns its place with distinct semantics. The Returns stanza is slightly redundant since an output schema already exists, a minor wasted line in an otherwise tight docstring.

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 an 8-parameter mutation tool with zero schema description coverage and no annotations, the description is nearly complete: every parameter is documented and the return shape is noted. Missing preconditions (key existence, valid object) and any note about interaction with keyframing or undo keep it from being fully complete.

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 0%, so the description must compensate and it does: all eight parameters are explained, including value ranges (-10.0 to 10.0), defaults (0.0 for slider_min, 1.0 for slider_max, Basis for relative_key), and the "" sentinel for vertex_group. This adds meaning well beyond the bare string/number/boolean types in the schema.

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: sets a shape key's blend strength plus its options. It is clearly distinct from sibling shape-key tools (add_shape_key, list_shape_keys, remove_shape_key, keyframe_shape_key, move_shape_key_vertices), so an agent can pick it without opening other 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?

Usage is only implied by the verb 'set' and the parameter list; there is no statement of when to prefer this over keyframe_shape_key, nor any prerequisite such as the shape key needing to already exist via add_shape_key. Adequate but leaves routing/precondition inference to the agent.

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