set_render_engine

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

With no annotations present, the description carries the full burden, and it partially meets it by disclosing the return value ('Confirmation dict with the active render engine'). It does not say whether the change is scene-persistent, whether it invalidates existing render settings, or whether it requires an active scene/context, which matters for a mutation tool with zero annotation coverage.

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?

Front-loaded with the action, then a compact Args/Returns block with no filler. The docstring scaffolding is mildly templated but costs almost nothing for a one-parameter tool.

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?

An output schema exists, so the Returns line need only corroborate it, which it does. For a simple one-parameter setter this is nearly adequate, but the missing BLENDER_EEVEE_NEXT option and the absence of any persistence or context requirement keep it from being 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% and the enum is the only semantic carrier, so the description must compensate. It attempts this by listing 'BLENDER_EEVEE, CYCLES, BLENDER_WORKBENCH' — but the schema enum also includes BLENDER_EEVEE_NEXT, which the description omits. The list is therefore both redundant with the schema and incomplete, risking an agent believing BLENDER_EEVEE_NEXT is invalid.

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: 'Set the render engine.' An agent immediately knows the operation and there is no competing sibling for this specific scene-level setting. It does not, however, position itself against adjacent tools like set_render_samples or set_viewport_shading, which contextually touch similar render configuration.

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?

No when-to-use guidance, no prerequisites, no mention of when this must be called relative to render_image or render_animation. The usage is only implied by the tool name itself, so an agent that is unsure whether engine changes persist or apply per-render gets no help.

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