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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the safety profile is fully covered and the description need not restate it. The description usefully characterizes the shape of the data returned (account: noAccess/user/admin; container: read/edit/approve/publish), which is real added context, but it says nothing about authorization requirements or whether the visibility of results is scoped to the caller's own permissions.

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?

A single front-loaded sentence with an em dash and one parenthetical; nothing is wasted and the core action leads. The permission-level enumeration is dense but earns its place by defining the returned vocabulary, though it could be split for readability.

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 an output schema present, return formatting is out of scope, and the remaining needs for a one-optional-parameter, read-only listing tool are covered: what is listed, at what granularity, and how to supply the account. Sufficient for an agent to call it 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?

Schema description coverage is 0% for the single `account` parameter, so the description must carry the burden — and it does, explaining that the value comes from list_gtm_accounts and may be a name or id, plus the default behavior when empty. It stops short of describing what happens with an invalid or ambiguous account value.

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 ("Lists the USER PERMISSIONS of a GTM account") and goes on to enumerate exactly what the data contains — access level, account vs. per-container scopes. It does not explicitly distinguish itself from the sibling write tool manage_gtm_permissions, so the differentiation is implied by the verb rather than spelled out.

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?

Usage is only implied: the parenthetical "empty if only one" tells the agent when the parameter may be omitted, and list_gtm_accounts is named as the source of the account value. There is no explicit statement of when to call this versus manage_gtm_permissions, nor any prerequisite (e.g., that the caller must already have account access) to view permissions.

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