List GTM Accounts

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

The description adds useful context beyond the annotations by clarifying the scope ('accessible by the service account') and the return payload ('IDs, names, and paths'). This complements the readOnlyHint and idempotentHint annotations without contradiction, though it does not discuss rate limits or error behavior.

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 a single, concise sentence that front-loads the verb and resource, includes essential scope details, and contains no redundant words. Every phrase adds value.

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 list operation with one optional parameter and no output schema, the description provides all necessary information: purpose, scope, and return fields. It is sufficiently complete for an agent to use the tool correctly.

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 single parameter page_token is fully described in the schema with a clear explanation. The tool description itself does not add parameter information, but given 100% schema coverage, the baseline 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 'List all Google Tag Manager accounts accessible by the service account' with an explicit verb and resource. It distinguishes from sibling list tools (e.g., gtm_list_containers) by naming the resource type and adds scope ('accessible by the service account') and return fields ('IDs, names, and paths').

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 usage context by noting it lists accounts accessible by the service account, which hints at discovery of available accounts. However, it does not explicitly state when to use this tool versus alternatives or mention any preconditions or follow-up tools.

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