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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered. The description adds real behavioral value beyond that by distinguishing container_id (numeric, tool-consumable) from public_id (GTM-XXXXXXX, UI-visible) and enumerating the container_type values returned, which is what an agent needs to pick the right ID downstream.

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 scope, then the return fields, then a reference link. Every sentence is short and purposeful, though the API documentation URL is marginal payload for selection decisions.

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?

An output schema exists, so return-value documentation is not required, and annotations cover the read-only safety profile. The description supplies scope, the account-hierarchy relationship, and ID semantics, which is sufficient; pagination and permission requirements are the only unaddressed gaps.

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 the single parameter already documents its default, the config fallback, and the error condition when neither is set. The description adds no parameter-level detail beyond what the schema provides, 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 all containers under a GTM account') and scopes it to the GTM account hierarchy, which separates it from lookalikes such as list_gtm_accounts, list_gtm_tags, and list_gtm_workspaces. Naming the returned identifiers (container_id, public_id) further pins down what this tool 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?

It implies usage by noting container_id is the input needed by audit_event_coverage, which is a genuine downstream-routing hint. However, it never states the when-to-use prerequisite chain (call list_gtm_accounts first, or rely on config) nor any exclusions versus the other GTM list tools; that guidance lives only in the schema's parameter description.

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