create_material_function_expression

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

Annotations already declare readOnly=false, destructive=false, idempotent=false, openWorld=false, so the write/non-destructive/non-idempotent profile is covered. The description adds value by disclosing that the created node must be wired and the function recompiled for changes to take effect, which is behavioral context not in the annotations.

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 front-loaded sentences plus a compact Returns block. Every sentence earns its place: purpose, sibling disambiguation, workflow, and return shape with no 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?

There is no output schema, so the inline Returns object legitimately fills that gap, and the description covers purpose, disambiguation, follow-up workflow, and return shape. Nothing an agent needs to invoke this write tool correctly is missing.

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%, so the schema already documents all four parameters with examples and defaults. The description adds only the notion of scope (inside a function's graph) and does not elaborate on any parameter beyond what the schema provides; baseline 3 is appropriate.

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+resource ('Create a new UMaterialExpression node') and immediately disambiguates from the closest sibling by explaining it is 'same shape as create_material_expression, scoped to a function instead of a material.' An agent can distinguish it from create_material_expression 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?

Names the concrete follow-up tools ('connect_material_function_pins to wire it and recompile_material_function to recompile'), giving a clear workflow context. It lacks an explicit when-not-to-use or prerequisite statement, so it stops short of the full 5.

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