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

Annotations already declare the safe mutation profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true); the description adds genuine value on top by disclosing the validation failure mode ("account_id ist rein numerisch, sonst {"error":"invalid_id"}") and the required post-creation linking step. It omits permissions/scope requirements and whether creation is idempotent or rate-limited.

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 core action, then the sequencing instruction, then the parameter caveats — every sentence carries actionable information. The telegraphic parentheses style is dense but not padded.

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?

Output schema exists, so return values need not be explained, and the description covers creation, the required wiring step, and the trickiest parameter constraints. What remains missing (required OAuth scopes, whether the container starts unpublished, name uniqueness) is secondary for a create call with a documented response.

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 coverage is 0%, so the description must carry the burden, and it largely does: it supplies the missing enum for usage_context (web | server | android | ios | amp), the numeric-only constraint on account_id with the exact error shape, and the meaning plus optionality of workspace. Only 'name' is left unexplained, which is self-evident.

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 opens with a specific verb and resource ("Neuen GTM-Container anlegen") and immediately scopes it with the allowed usage_context values, which no sibling gtm_ tool offers. It is clearly distinguishable from gtm_list_containers and gtm_create_workspace, and it names the follow-up step that makes the created container usable.

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 gives a concrete workflow prerequisite: after creating, link the container via workspace_configure_source (source='gtm') so the remaining gtm_ tools can use it. It does not mention when not to use it (e.g., checking gtm_list_containers first to avoid duplicates) or alternatives, so it falls short of the explicit when/when-not bar.

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