Create a container

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

Adds meaningful behavioral context beyond annotations: discloses that containerId and publicId are server-assigned, and states the required OAuth scope. Annotations already indicate a non-read-only, non-idempotent operation, and the description is consistent with that.

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 sentences with the purpose front-loaded. No filler; each sentence earns its place (purpose, usage_context clarification, return value/scope).

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?

Given the simple three-parameter schema and no output schema, the description adequately covers what the tool does, return format, and authentication requirement. It could mention if account_id must reference an existing account, but that is implicit. Overall sufficient for an agent to invoke 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 covers all parameters with descriptions (100% coverage), so baseline is 3. The description adds a brief clarification that usage_context declares the platform, but the schema already lists the same documented values. No extra semantics are provided for name or account_id.

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 'Creates a new container in a GTM account' with a specific verb and resource. It distinguishes itself from sibling tools like create_workspace or get_container by naming the resource type and including relevant context about usage_context.

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?

Provides contextual usage guidance by explaining the usage_context parameter values and specifying the required permission scope (tagmanager.edit.containers). It does not explicitly name alternatives, but the context is clear and no exclusionary guidance is needed.

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