create_variable

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

With no annotations, the description carries the full burden. It helpfully discloses that resolvedType is an enum-like set and clarifies that EASING/TIMING hold motion curves and durations, but it says nothing about mutation effects, duplicate-name behavior, required modes, scope semantics, or error conditions.

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 sentences, front-loaded with the action, with no filler. The trailing explanation of EASING/TIMING is slightly tangential but earns its place by documenting a value the schema never documents.

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 creation tool with 7 parameters, nested valuesByMode/valuesByModeEntries objects, no annotations, and no output schema, the description covers only the type field. It omits how values-by-mode should be supplied, what scopes do, and what the creation side effects are, leaving an agent under-informed for the call.

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% across 7 parameters, so the description's enumeration of resolvedType values is genuinely additive and the only documentation of that critical field. However, collectionId, name, scopes, description, valuesByMode, and valuesByModeEntries remain unexplained, so it only partially compensates for the coverage gap.

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 and resource ('Create a local variable in a collection') plus the value-setting scope ('set values by mode'), which is enough to distinguish it from create_variable_collection, set_variable_values, and rename_variable. It stops short of naming siblings explicitly, so it is clear but not maximally differentiated.

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 when-to-use or when-not-to-use guidance and no mention of alternatives such as set_variable_values (for populating an existing variable) or create_variable_collection (for the container itself). The phrase 'in a collection' only weakly implies a precondition that a collection must already exist.

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