List Tag Manager accounts

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond annotations by noting the scope is 'every Google Tag Manager account the authenticated user can access' and that it is the entry point for discovering accountId.

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?

Three short sentences deliver function, usage ordering, and safety in a front-loaded way. There is no filler or repetition of schema details.

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 simple read-only list operation with no required parameters, the description gives the agent everything needed: what it lists, that it is the first step, and that it yields accountId. The absence of an output schema is mitigated by the explicit mention of discovering accountId.

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 (limit and pageToken) are already fully documented in the schema. The description does not add parameter-level detail, but the baseline of 3 is appropriate because the schema carries the explanatory burden.

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 states a specific verb and resource: 'Lists every Google Tag Manager account the authenticated user can access.' It also distinguishes this tool from sibling tools by placing it first in a clear sequence (gtm_list_containers, gtm_list_workspaces), so an agent can tell what it is for.

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 gives explicit usage direction: 'Use this FIRST to discover accountId, then gtm_list_containers, then gtm_list_workspaces.' This tells the agent exactly when to invoke this tool and how it fits into a larger workflow, leaving little to inference.

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