get_material_instance_param_overridden

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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuine beyond-annotation context: 'Editor-only' runtime scoping and the semantic caveat that 'an inherited value and a locally-set identical value read the same', which explains why this read exists at all.

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 core question, then the discriminator rationale, the use case, and the return shape. Every sentence carries meaning, though the middle sentences are slightly dense and the return-shape line could be trimmed if an output schema existed. No wasted filler.

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 read tool with no output schema, the description supplies the return shape (material_instance_path, parameter_name, association, overridden), so an agent knows what comes back. Annotations and schema cover the rest. Adequate; the only minor gap is that the association parameter's effect on the returned flag is not spelled out.

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 coverage is 100%, and the schema documents all three parameters including the association enum values (Global/Layer/Blend). The description adds only 'one named parameter' and 'set on the INSTANCE', which maps to but does not extend the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Return the override flag') and resource ('for one named parameter') and frames the exact question it answers ('Is this parameter set on the INSTANCE, or just inherited from the parent?'). It also distinguishes itself from the plain value read (get_material_instance_params) by explaining the inherited-vs-identical-local ambiguity that a value read cannot resolve.

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?

Gives concrete when-to-use guidance: 'Use it to confirm a write actually landed on the child' and the read-only vendor-material case. It contrasts against a 'plain value read' generically, but does not name the sibling tool (get_material_instance_params / get_material_instance_base_overrides) explicitly, keeping it just short of a 5.

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