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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds behavior beyond that: workspace_id must be purely numeric or the call returns {"error":"invalid_id"}, and the workspace slug is only needed when more than one workspace exists. Return shape is left to the output schema, which is acceptable.

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?

Four short clauses, front-loaded with the purpose, then the diagnostic trigger, then the two parameter facts. Nothing is redundant, though the telegraphic em-dash style is slightly harder to parse than plain sentences.

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 read-only two-parameter diagnostic with an output schema and existing annotations, nothing an agent needs in order to call it correctly is missing: purpose, trigger, both parameter semantics, and the invalid-input behavior are all present.

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%, so the description carries the full burden and does: workspace_id is documented as strictly numeric with the exact failure mode, and workspace is documented as the customer workspace slug that is optional when only one workspace exists. Both parameters gain meaning that the bare schema does not provide.

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States a specific verb+resource: show open (unpublished) changes plus merge conflicts of a GTM workspace. It also distinguishes itself from the neighboring gtm_list_workspaces / gtm_sync_workspace by framing the call as a diagnostic, so an agent can tell it apart without opening the schema.

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?

Gives an explicit trigger: use it when gtm_create_version or gtm_sync_workspace fails. That names the alternative tools and the condition that selects this one. It does not state a 'when not to use' case (e.g. plain workspace listing or routine publishing), which keeps it short of a 5.

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