material_set_field

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

Annotations already declare false for readOnly, destructive and openWorld, so the agent knows this is a non-destructive mutation within the open scene. The description adds the accepted value type space (number/boolean/enum/color), which is useful, but says nothing about overwrite behavior, prerequisites (material must exist), or reversibility. With annotations carrying the safety profile, a 3 fits.

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?

Two short sentences, no filler, with the routing rule front-loaded right after the capability statement. Every clause earns its place by either defining scope or directing to a sibling.

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 return values need not be described, and annotations cover the safety profile. Given that, the description plus schema is sufficient to call the tool correctly except for the minor name/slot ambiguity, which the sibling tools' naming conventions resolve.

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% across four required parameters, so the description must compensate and only partially does: it clarifies that 'field' takes a name from material_get and that 'value' is a number, boolean, enum or color. It says nothing about 'name' or 'slot', which are left ambiguous (material name vs. slot identifier/index).

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 (a field of a material slot) and enumerates the exact field types it handles: number, boolean, enum, color. It explicitly disambiguates from the sibling material_set_texture in the same breath, so an agent can pick between them without opening either schema.

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?

Explicitly routes texture fields to material_set_texture and tells the agent to obtain field names from material_get, which is real when/where guidance. It does not mention material_set_cutout or material_set_subroutine as alternatives, so the routing picture is incomplete rather than fully closed.

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