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

No annotations are provided, so the description carries the full burden. It discloses that the organization is derived from context rather than passed (a genuine auth/scoping insight) and the schema covers idempotency, but it says nothing about duplicate-name behavior, permissions, or side effects of a mutation.

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?

Two sentences, both front-loaded: the core action first, the critical constraint second. No filler or repetition of schema content.

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 100% schema coverage and no output schema, the parameters are well covered, but for an unannotated create tool the definition is silent on duplicate handling, failure modes, and post-creation state. It is adequate but leaves gaps an agent would want filled.

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 100%, so the baseline is 3, but the description adds real value by warning against an organization identifier that does not appear in the schema, preventing a hallucinated parameter. It leaves the other five documented fields entirely to the schema, which is acceptable here.

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 ('Create a new billing customer'), which clearly separates it from sibling writes like create_project, create_task, and update_customer. It reaches clarity without explicitly naming which sibling to prefer, so it falls just short of a 5.

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 one concrete usage rule ('never pass an organization id') but says nothing about when to create a customer versus reusing an existing one, or when to prefer update_customer. A useful constraint is present, but the when-to-use/when-not dimension is only implied.

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