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

Annotations mark it destructive and non-read-only, and the description adds substantial context beyond them: a ~10 minute feature-engineering refresh, sibling labels not mentioned are preserved, duplicate sourceKeys and name collisions reject the whole array, delete-then-re-add is permitted in either order, and an auth/route constraint (admin-only, Clerk-only writes). This is far more than the annotations convey.

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?

Purpose and the dryRun-first workflow are front-loaded, and given the merge/collision/ordering complexity few sentences are wasted. It is a dense single paragraph rather than a structured list, which makes the many constraints harder to scan, but it is 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?

Despite no output schema, the description covers what dryRun returns (the full next labels document, preview only) versus what the real write does, plus ordering, collision, and auth constraints. An agent has everything needed to construct a correct call for this high-risk mutation.

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%, so baseline is 3, but the description adds array-level semantics the schema cannot express: ids are generated for add, update/delete target an id from list_label_dimensions or an earlier add in the same array, default name is a sanitized sourceKeys[0], and moving a key with update on the owner in the same array. It largely restates but usefully frames the per-item fields in operation terms.

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?

Specific verb and resource: 'Merge add/update/delete operations onto published label dimensions, then replace the stored document.' It immediately distinguishes itself from read-only siblings (list_label_dimensions, list_label_dimension_usages) and from the virtual-dimension publish path, so an agent can route correctly without opening a 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?

Explicit when-to-use and when-not-to: dryRun defaults true for preview, persist once with dryRun:false and confirm:true, check list_label_dimension_usages before rename/delete, demo orgs are read-only, dimensionsAdminOnly requires an org admin, and real writes happen through Clerk MCP only (the service route is dry-run only). It also warns not to call publish twice.

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