List Tag Manager containers

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

The readOnlyHint and destructiveHint annotations already indicate the tool is read-only and non-destructive. The description adds no additional behavioral details such as side effects, permissions, rate limits, or edge cases, so it does not go beyond the annotations.

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 concise and well-structured, consisting of two clear sentences. It avoids unnecessary wording and efficiently communicates the tool's purpose and output.

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?

The description lists the specific fields returned (container_id, public_id, name, usage context), which is sufficient given no output schema is provided. It lacks details on pagination or error handling, but for a simple list operation this is not a significant gap.

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 schema defines one parameter, gtm_account_id, with a default of empty string. The description mentions 'under a GTM account' but does not further explain the parameter's format, source, or requiredness. Since schema coverage is 100% and the description adds minimal context, a baseline score of 3 is appropriate.

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 clearly states the action ('List all containers') and the resource ('under a GTM account'), and it distinguishes this tool from siblings by focusing on containers rather than accounts, tags, triggers, or other entities. It also lists the returned fields, which further clarifies its purpose.

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 provides clear context by stating that it returns the container_id needed by audit_event_coverage and the public_id shown in the UI, implying when to use it. However, it does not explicitly contrast it with other listing tools (e.g., list_gtm_accounts, list_gtm_tags), so it lacks explicit exclusions or alternatives.

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