set_variable_value

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

No annotations are provided, so the description carries the full behavioral burden. It is a mutation tool, yet nothing is said about permissions, whether existing values are overwritten, whether the variable must already exist, or what happens when modeId is omitted (that default only appears in the schema).

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?

Two compact sentences, front-loaded with the core action. No padding, though the second sentence largely duplicates the schema's value description rather than adding information.

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 3-parameter mutation with no annotations and no output schema, the description is minimally viable: the parameters are fully documented in the schema, but the tool's side effects and mode semantics are left unexplained. Adequate but with clear 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 100%, so the baseline is 3. The description's only parameter-level addition is restating the alias shape ({aliasOf: variableId}), which the schema already documents; it adds no new meaning for variableId, modeId, or the literal value forms.

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+resource+scope: 'Set the value of a variable for a mode.' An agent can distinguish it from create_variable/delete_variable, though it does not explicitly separate itself from the semantically adjacent bind_variable, which also touches variable values.

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?

No when-to-use guidance, no alternatives named, no prerequisites. The description never tells an agent why it would pick this over bind_variable or create_variable, or when a modeId should be supplied versus omitted.

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