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

Annotations only disclose the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description goes well beyond them by disclosing the quota model (plans include a fixed number of active clients), the quota-exhaustion failure mode, and required authentication/plan prerequisites — exactly the mutation context an agent needs before invoking.

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, front-loaded with the action, then domain context, then prerequisites and failure mode. No sentence is redundant and nothing is buried.

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 one-parameter mutation with annotations covering safety, the description covers prerequisites, quota limits, and failure behavior. The only gap is that with no output schema it never indicates what a successful call returns (e.g., a new client identifier), which an agent would need to chain a follow-up call.

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% and there is a single parameter, so the schema already carries the naming guidance ("as the customer would say it"). The description adds domain framing — that a workspace maps to one brand — but no syntax, format, or validation detail beyond the schema, so 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 first sentence names a specific verb and resource ("Add a client workspace to the account"), and the second sentence clarifies what that resource contains, which removes ambiguity about the domain object. It does not explicitly contrast itself with any sibling such as list_clients or order_report, so it lands at clear-but-undifferentiated.

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?

The description states concrete preconditions for use ("Needs the May plan and an X-Mako-Key header") and a failure condition ("fails when the roster is full"), which is stronger than generic context. It stops short of naming alternatives or when-not-to-use guidance, so it is not a 5.

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