Bind Variable

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

Annotations provide idempotentHint=true and openWorldHint=true, which cover behavioral transparency. The description adds no further behavioral details such as side effects, permissions, or rate limits. Since annotations already handle the safety profile, the description's contribution is minimal, earning a 3.

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 two sentences long with no unnecessary words. It is front-loaded with the core action and includes a usage directive. Every sentence earns its place, achieving maximum 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 (4 params, nested objects, output schema), the description covers the essential functionality and use case. However, it omits details like the verification role of nodeName and the implications of openWorldHint. The presence of an output schema slightly reduces the need to describe returns. Overall, it is adequate but could be slightly more complete.

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?

All parameters are documented in the schema (100% coverage). The description adds a high-level explanation of the two use cases (binding vs. explicit mode), which clarifies the overall purpose beyond individual parameter descriptions. This extra context justifies a 4 over the baseline of 3.

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: binding a variable to a node property or setting an explicit variable mode. It uses specific verbs ('bind', 'set') and resources ('variable', 'node property', 'variable mode'), and distinguishes itself from literal node_set_* tools by mentioning design token tracking.

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?

Explicitly states when to use this tool: 'Use instead of a literal node_set_* when the value should track a design token.' This provides clear guidance on when to prefer this tool over alternatives, effectively covering usage context and exclusions.

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