Preview a GTM workspace

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

Goes well beyond annotations: it clarifies why readOnlyHint=true holds despite needing a write token ('no version is created, nothing goes live') and discloses the exact auth prerequisites (scope tagmanager.edit.containerversions, writes enabled for the client). That reconciles an otherwise confusing safety/scope pairing and is exactly the kind of context annotations cannot carry.

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?

Front-loaded with the action and outcome, then behavior guarantees, then auth requirements. Three dense sentences with little waste; 'so there is nothing to apply' mildly restates 'it changes nothing', which keeps it below 5.

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 no output schema, the description still specifies what gets reported (compiler errors, merge conflicts, workspace contents), confirms nothing persists, and covers auth scope. Nothing an agent needs to invoke this correctly is missing.

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%, so both parameters (client_id, workspace_id) are already fully documented in the schema, including the 'never the Default Workspace' constraint. The description only refers to 'a workspace' and 'the client' generically and adds no syntax or format detail, so 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 ('compile a workspace into a throw-away preview version') and names the outputs ('compiler errors, merge conflicts and what it holds'). An agent can distinguish this from siblings like gtm_plan_workspace_create or gtm_workspace_status without opening a schema.

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?

Frames the tool as the 'Preview step of a GTM plan' and rules out any follow-up ('there is nothing to apply'), which tells the agent when in a workflow to call it. It does not explicitly name alternative siblings (e.g. gtm_workspace_status) or exclusions, so it stops short of the top score.

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