update_user_variable

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

With no annotations, the description carries the full burden. It adds value by explaining the vtype parameter (integer codes for variable types), but does not disclose behaviors like what happens if the variable does not exist, permissions needed, side effects, or whether it returns a response. This is adequate but not comprehensive.

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 extremely concise: two sentences, with the first clearly stating the action and the second adding essential parameter context. Every word serves a purpose, and the information is front-loaded. No extraneous content.

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 3 required parameters and no annotations, the description covers the purpose and one parameter well, but omits important context like what happens if the variable doesn't exist, constraints on value format for different types (though date/time formats are given), and the return behavior despite an output schema existing. It meets minimum completeness but has 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 0%, so the description must compensate. It provides clear semantics for the vtype parameter (mapping integer to string types), but offers no additional meaning for name or value beyond their schema titles. This partial coverage is sufficient for a simple tool but not outstanding.

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 'Update an existing user variable' with a specific verb and resource. This directly differentiates it from sibling tools like add_user_variable (create) and delete_user_variable (delete), as there is no ambiguity about its purpose.

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 does not provide explicit guidance on when to use this tool versus alternatives. It only states the action, leaving the agent to infer that it should use add/delete for other operations. No when-not or alternative tool names are mentioned.

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