Create a billing account

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

Annotations only supply destructiveHint=false and a title, so the description carries the real burden — and it does: it discloses the auth prerequisite, the non-obvious side effect that the new account becomes the active account (changing what projects_create/projects_list target), and the return payload. Creation is not idempotent-safe by implication, and the 'check first' warning covers the duplicate-account risk.

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 tight sentences, front-loaded with the action, followed by prerequisite, side effect, return value, and the routing hint. Every sentence carries information an agent needs and there is no filler or restatement of the title.

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?

There is no output schema, and the description compensates by stating what is returned (the new account's id and name). Combined with the login prerequisite and the active-account side effect, an agent has everything needed to call this correctly and sequence it properly.

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 name, email, and currency (including the immutable-after-creation constraint and default) are already fully documented. The description adds no parameter-level detail beyond that, which is the expected baseline when the schema does the heavy lifting.

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 and resource ('Create a new billing account (organization)') plus what the resource holds ('projects and payment details'). It is immediately distinguishable from siblings like accounts_list, accounts_use, and projects_create, which are all named explicitly.

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 explicit preconditions ('Requires a prior platform login (use the login tool first)') and an explicit when-not/gate ('Most users need only one account — call accounts_list first to check whether a suitable one already exists'). Nothing about tool selection is left to inference.

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