mat_connect_expressions

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

No annotations are provided, so the description carries the full responsibility for behavioral disclosure. It only states the action 'Connect' and a generic 'Returns JSON StructuredResult.' It does not mention that this is a mutation (modifies the material asset), whether recompilation is required, if existing connections will be broken, or any side effects. This is a significant gap for a tool that modifies graph connections, leaving the agent without guidance on consequences or prerequisites.

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?

The description is structured with clear sections (intro, special case, common names, Args, Returns, KB, Example) and front-loads the core action. While it is longer than average, every section contributes necessary information given the tool's complexity (5 parameters, special-case handling). It is not verbose or redundant; it strikes a good balance between thoroughness and efficiency.

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?

Given the tool's complexity and the 0% schema coverage, the description covers all parameters, the special root-input case, common pin names, and includes an example and a KB reference. It also notes that from_expression_name comes from mat_add_expression, implying a required sequence. An output schema exists, so return values are not needed in the description. It is missing explicit prerequisites (e.g., material must exist, expressions must be added first) and failure modes, but covers the essential context well.

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%, so the description must compensate. It does this thoroughly with an 'Args' section that explains each of the five parameters, provides examples (e.g., 'RGB', 'A', ''), clarifies the meaning of empty strings for root connections, and references mat_add_expression outputs as a source for from_expression_name. This adds substantial meaning beyond the bare schema and effectively documents parameter usage.

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?

The description clearly states the tool's purpose: 'Connect two material expression nodes or connect an expression to a material input.' It uses a specific verb-resource pair and distinguishes itself from sibling tools like mat_add_expression (which adds nodes) and mat_compile (which compiles). The special case for root input connections further clarifies the exact scope, leaving no ambiguity about what the tool does.

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?

The description provides usage context for the special case of connecting to material root inputs (using '' for to_expression_name), lists common input names, and references mat_add_expression outputs for from_expression_name. However, it does not explicitly state when to use this tool versus alternatives, nor does it provide clear exclusions. The guidance is implicit rather than explicit, so it does not fully meet the 'explicit when/when-not/alternatives' standard.

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