content_set_material_instance_parameter

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

With no annotations, the description carries the full burden. It does usefully disclose that the value is validated and that the asset is saved (a persistent side effect), but it does not say what happens on validation failure, whether other existing overrides are preserved, or what the save touches.

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?

A single sentence with no filler, and the mutation plus its persistence effect are front-loaded. Slightly clipped for a state-changing tool, but every clause earns its place.

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?

Output schema exists and all three params are documented, so return values need no explanation. However, for an unannotated mutation the description should say more about validation failure behavior and whether unrelated overrides are disturbed.

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%, and the schema already explains materialInstanceId (GUID from content_search), parameterName (existing public parameter), and value (matching declared type). The description adds only the 'one parameter' framing, so the baseline 3 applies.

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 ('Sets'), a specific resource ('parameter override on a MaterialInstance'), and the persistence side effect ('saves the asset'). It is clearly distinct from content_create_material_instance or editor_set_member, though it does not name those siblings explicitly.

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?

'on an existing MaterialInstance' and 'one validated parameter override' imply preconditions (instance must already exist, one parameter per call), but the description never states when to prefer this over content_create_material_instance or editor_set_member, nor any exclusions.

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