set_variable_values

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

With no annotations, the description carries the full burden of behavioral disclosure, but it provides only a generic 'Update' statement. It does not say what the operation mutates, whether changes are destructive or reversible, what permissions are required, or how mode values are handled.

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 single sentence is front-loaded and free of fluff, which is structurally efficient. But it is under-specified rather than truly concise: the brevity comes at the cost of meaningful detail for a nested mutation tool.

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?

For a mutation tool with three parameters, nested objects, no annotations, and no output schema, the description is far too thin. It omits parameter formats, mode behavior, mutation effects, and any operational caveats an agent would need before calling it safely.

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 for all three parameters. It vaguely implies mode-based values but does not explain variableId, the valuesByMode object shape, or the optional valuesByModeEntries array beyond what the bare schema names suggest.

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?

States a specific verb ('Update'), resource ('variable's values'), and scoping method ('by mode'), so the core action is clear. However, it does not distinguish this operation from nearby siblings such as set_variable_mode or set_node_explicit_variable_mode, leaving some selection 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?

There is no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. The definition leaves the agent to infer usage context entirely.

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