update_aux

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

The description simply states 'update' without elaborating on behavior. The annotations indicate non-destructive write, but the description does not confirm idempotency, error handling, or what happens if the variable does not exist. It adds minimal value beyond the 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 a single, clear sentence of 4 words. It is front-loaded and contains no fluff. However, it could benefit from additional context without losing conciseness.

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 (7 parameters including nested graphical_function), no output schema, and no behavioral details, the description is too sparse. An agent lacks information about what the tool returns, whether it modifies in place or returns a new resource, and error conditions. Sibling tools like add_aux likely have more detailed descriptions; update_aux should at least mention that it modifies an existing variable.

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 all 7 parameters with full descriptions (100% coverage). The tool description 'Update auxiliary variable fields' does not add any additional meaning or examples for complex nested parameters like graphical_function. 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 'Update auxiliary variable fields' clearly identifies the verb 'update' and the resource 'auxiliary variable fields'. It distinguishes itself from sibling tools like add_aux (which creates) and delete_variable (which deletes). No ambiguity.

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 no guidance on when to use this tool over alternatives. It does not mention prerequisites (e.g., the auxiliary variable must exist), nor contrast with add_aux for creation or update_stock/update_flow for other variable types. An agent would have no context for when it is appropriate.

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