Bind Variable

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

Annotations supply idempotentHint and openWorldHint, but the description adds behavioral nuance beyond those: the design-token tracking semantic and the ordering constraints that affect outcomes. It does not contradict annotations. A slight gap is that it doesn't mention potential side effects of setting explicit variable modes, but the value added is solid.

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?

Three sentences, each earning its place: functionality, usage guidance, and ordering rules. No redundancy or fluff; front-loaded with the core purpose.

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 (nested objects, 4 params, output schema present), the description covers purpose, usage distinction, and ordering constraints. The schema handles parameter details, and annotations handle idempotency/open-world semantics, leaving no significant gaps.

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%, with each parameter already described in detail. The description adds a high-level reason for binding ('track a design token') but doesn't provide additional parameter-level semantics beyond what the schema already covers. 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?

The description clearly states the tool binds a variable to a node property or sets an explicit variable mode, with a specific verb and resource. It distinguishes itself from sibling tools like node_set_fill by noting it should be used 'instead of a literal `node_set_*`' when tracking design tokens.

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?

Provides explicit guidance on when to use this tool versus alternatives: 'Use instead of a literal `node_set_*` when the value should track a design token.' It also gives ordering rules (set auto-layout before binding padding/spacing, set solid fill before binding colour token), which contextualizes usage.

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