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

Annotations declare the mutation profile (destructive, open-world, non-idempotent), so the description need not restate safety. It does add real value: the account is created as a child of the authenticated account, and the response carries a child API token that must be stored securely and scoped to that child. It omits any warning that repeated calls create additional accounts, which is the one gap given non-idempotency.

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 tight sentences: purpose first, then the pre-call precondition, then the post-call handling of the returned token. Nothing is repeated from the schema and every sentence carries operational weight.

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 non-idempotent, destructive creation tool with 10 parameters, the definition covers purpose, prerequisites and the sensitive return value well. It stops short on the optional business/identity parameters and gives no guidance on what happens to the account after creation or on duplicate handling, leaving meaningful gaps for a tool of this complexity.

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 only 30% across 10 parameters, so the description carries the burden — but it only reiterates cell, email and password, which are already the documented fields. The seven undocumented parameters, particularly the optional vatno, address, id_number, business_reg and business_name, are never explained as to when they should be supplied or how they change the created account.

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 normal SIMcloud account under the authenticated account for a client application user') and scopes the account type and parent relationship. None of the sibling tools (orders, SMS, wallet, lookups) register users, so the distinction is unambiguous without opening the 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?

Gives a pre-call checklist ('Confirm that the person consents... and that their cell number, email and password are correct'), which implies when the tool is appropriate. However, it never states when not to use it, and with idempotentHint=false it gives no warning about duplicate registration on repeat calls. Usage context is implied rather than explicit.

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