add_variable_mode

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

Beyond the annotations (destructiveHint: true), the description discloses the specific error condition for free plans, the one-mode-per-collection constraint, and the correct fallback behavior. It also instructs the agent to stop retrying and switch strategies, which is critical for correct autonomous operation. No contradiction with 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?

The description is well-structured and front-loaded with the core action. It contains three informative sentences without fluff, but the middle part on the workaround is slightly verbose. Overall, it is efficient but not maximally concise—every sentence earns its place, earning a 4.

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 simplicity (2 params, no output schema, no nested objects) and the presence of clear annotations, the description fully covers the essential aspects: the action, the free plan limitation, the error handling, and the workaround. No missing context for an AI agent to use this tool correctly.

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?

The input schema already describes both parameters (modeName and collectionId) with basic descriptions, achieving 100% schema coverage. The description adds example mode names and context about the free plan error, but does not provide additional semantic detail about the parameters themselves. Hence, a score of 3 is appropriate per the rubric (baseline for high schema coverage).

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 adds a new mode to an existing variable collection, with concrete examples like Light/Dark and Desktop/Mobile. It effectively distinguishes itself from sibling tools (e.g., add_page, bind_variable_to_node) by specifying the exact resource and action.

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 explains when to use the tool and, crucially, when not to—detailing the free plan limitation (1 mode per collection) and the error that will occur. Provides a clear alternative (name-prefix workaround) and instructs the agent to inform the user about the paid plan requirement. This is exemplary usage guidance.

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