gtm_list_variables

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds a genuinely useful behavioral fact beyond them: it automatically follows all result pages, so the agent knows it will not need to paginate manually. It says nothing about result volume or error behavior, keeping it short of a 5.

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?

A single sentence with zero filler that front-loads the action, the scope and the pagination behavior. Every clause earns its place.

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?

With an output schema present, rich annotations and fully documented parameters, the description only needs to add what structured fields cannot. It supplies the auto-pagination behavior and scope, though it leaves usage routing to the sibling tools unaddressed.

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% and each parameter (account, container, workspace) is already documented in the schema, including the note that workspace may be omitted for reads. The description adds no format or default detail beyond that, so the baseline 3 applies.

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 ('List every user-defined variable') plus its scope ('in a workspace'), which cleanly separates it from the singular gtm_get_variable sibling. It does not, however, explicitly contrast itself with the other list_* tools in the family, so sibling routing relies on the name alone.

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 never says when to prefer this tool over gtm_get_variable or how it relates to the other list_* tools, nor does it state prerequisites such as needing a container first. Usage is only inferable from the verb 'List every', which is minimal guidance.

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