Update Variable

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It prominently states that the sent variable replaces the stored one and that omitted fields are cleared, which is a critical, non-obvious destructive behavior. This goes well beyond the schema and gives agents the essential safety warning.

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 exactly two sentences, front-loaded with the purpose and immediately followed by the most important operational warning. Every word earns its place, and there is no redundant 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 the tool's complexity (6 params, nested object, output schema), the description covers the key behavioral caveat and the recommended workflow. It does not discuss authorization or the fingerprint's optimistic concurrency role, but these are either implied by schema or less critical for correct invocation. Overall, it is sufficiently 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?

Schema coverage is 100%, so the baseline is 3. The description adds meaningful semantics to the 'variable' parameter by explaining the replace behavior and the read-modify-write workflow, which is not fully captured by the schema's 'Complete Variable resource' note. This pushes it above baseline.

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 action ('Update a variable in a workspace') with a specific verb and resource. It does not explicitly differentiate from sibling update_* tools, but the resource name is unambiguous and the reference to get_variable helps distinguish update from create/read operations.

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 gives concrete usage guidance: read the variable with get_variable first, send the whole object back with edits, and be aware that omitted fields are cleared. This is an explicit procedure, though it does not mention when not to use the tool or name alternative tools beyond get_variable.

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