create_custom_metric

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

With no annotations provided, the description carries the full responsibility for behavioral disclosure. It only states the creation action and enum values, without explaining side effects, required permissions, idempotency, or what the result of creation entails. This is a significant gap for a mutation tool.

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 concise, consisting of two short sentences, with no wasted words. The measurement_unit enumeration is a useful addition, though the structure could be improved by including required parameters or usage context.

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?

The tool has six parameters with no schema descriptions, no annotations, and no output schema. The description covers only the creation action and one parameter's enum values, leaving the purpose and semantics of the other parameters and the operational behavior unexplained. This is insufficient for effective tool selection and invocation.

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?

The description adds meaningful enumeration for the measurement_unit parameter, which is absent from the schema. However, the other five parameters (scope, description, property_id, display_name, parameter_name) receive no semantic explanation, and schema description coverage is 0%, so the description only partially compensates.

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 'Create' and the resource 'a custom metric', which is specific and distinguishes it from sibling tools like create_custom_dimension or list_custom_metrics. The verb+resource construction is unambiguous.

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 provides no guidance on when to use this tool versus alternatives such as create_custom_dimension or list_custom_metrics. There is no mention of prerequisites, exclusions, or alternative tools for different scenarios.

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