gtm_create_variable

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

There are no annotations, and the description discloses no behavioral traits beyond the basic action. It does not mention idempotency, side effects, required permissions, or error behavior, leaving the agent with no additional context about the operation's consequences.

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 a single sentence with no redundant words, making it highly concise and front-loaded.

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 tool with four required parameters and no annotations or output schema, the description is too sparse. It lacks any context about the expected JSON structure, return value, or prerequisites, making it insufficient for an agent to use confidently.

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 clarifies that variable_json is a full GTM Variable resource, adding meaning beyond the schema's bare property name. However, it does not explain the purpose of account_id, container_id, or workspace_id, though these are somewhat self-explanatory from their names.

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 uses a specific verb ('Create') and resource ('GTM Variable') and specifies the input as a 'full GTM Variable resource (JSON string)', clearly distinguishing it from sibling tools like gtm_update_variable or gtm_create_tag.

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 explicit usage guidance is provided regarding when to use this tool versus alternatives. The phrase 'from a full GTM Variable resource' implies a prerequisite but does not state when-not-to-use or name alternatives.

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