Disable Built-In Variables

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

Annotations declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true. The description adds that 'Tags or triggers still referencing them will break,' which clarifies the destructive impact beyond the annotation. This is valuable context for an agent evaluating risk.

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 two sentences, both essential: the action and the consequence. No filler, front-loaded with the verb and resource.

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?

Given the tool is a straightforward mutation with 4 well-documented parameters, no output schema, and strong annotations, the description covers the purpose and key side-effect. It could mention idempotency or repeated calls, but that's minor; completeness is high.

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%: each parameter (account_id, container_id, workspace_id, types) has a descriptive comment. The description itself does not add further parameter details, so baseline 3 is appropriate; no gaps to compensate.

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 ('Disable') and resource ('built-in variables in a workspace'), clearly distinguishing it from siblings like gtm_enable_built_in_variables and gtm_list_built_in_variables. It also notes the impact on dependent tags/triggers, adding purpose specificity.

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 implies when to use this tool (when you want to disable built-in variables) and warns about the consequence. However, it doesn't explicitly mention alternatives like enabling or listing, though the sibling list makes that context available. Adequate but could be more explicit.

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