connect_material_expressions

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

Annotations already disclose non-readonly, non-idempotent, destructive behavior, and the description adds the critical caveat that a true return only means the pin NAME resolved rather than that the edge was actually created. It also discloses that MakeMaterialAttributes accepts named pins that the graph walker reports as unnamed, including Displacement — behavior an agent could not infer from annotations or schema.

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?

Purpose is front-loaded, followed by naming constraints, the verification caveat, and an inline Returns block. Every sentence carries information, though the middle paragraph is dense and could be split for faster scanning.

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?

No output schema exists, so the description carries the return-value burden and does so with an explicit field list, and it also supplies the verification workflow and naming rules. For a 5-parameter graph-mutation tool, nothing an agent needs in order to call it 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 coverage is 100%, so the baseline is 3, but the description adds real semantic value beyond the schema: input pin names must omit spaces, and certain destination nodes accept pins the graph walker cannot enumerate. It does not clarify output-pin naming conventions or pin-index syntax, keeping it below a 5.

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: 'Wire one material node's output pin into another node's input pin', and adds scope language ('the only headless route to some pins') that distinguishes it from sibling wiring tools such as connect_material_function_pins, connect_to_material_output, and connect_pins. The agent knows exactly what graph mutation this performs without opening the 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?

Gives concrete operating context: use unsuffixed input names (BaseColor, not 'Base Color'), and verify the result via get_material_expressions/get_material_graph_info then compile and check get_material_stats. It does not explicitly state when to prefer this over the other connect_* siblings, but the naming rules and verification path are actionable usage guidance.

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