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

Annotations already declare non-readonly, non-idempotent, non-destructive, but the description adds substantial behavioral context beyond them: the 409 uniqueness failure, the one-artist-per-workspace constraint, the refusal until the workspace becomes a label, and the no-plan requirement. These are exactly the operational traits an agent needs before invoking a mutating create tool.

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 short sentences, each carrying distinct information: action, uniqueness/conflict rule, workspace constraint, and billing exception. It is front-loaded with the action and has no filler.

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 no output schema, the description explains the important preconditions and failure modes, which is more than most create tools provide. It does not say what the tool returns (e.g., the created artist object or ID), which is a minor remaining gap for a create operation.

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?

There is a single required parameter and the schema description coverage is 100%, so the schema already defines name fully. The description only repeats "by name" and adds no constraints, formats, or examples beyond the schema; the baseline 3 applies.

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 states a specific verb and resource ("Add an artist by name") and immediately clarifies scope: creation of an artist, not a rename or organization creation. An agent can distinguish it from rename_artist and create_organization without opening any 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?

It provides concrete preconditions and failure modes (unique per organization, 409 when taken; a second artist in a workspace is refused until it becomes a label via update_organization) and notes the tool works without a plan for onboarding. It stops short of explicitly naming when to prefer a sibling (for example, create_organization) or stating exclusions, but the usage context is clear.

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