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

With no annotations supplied, the description carries the full burden and does so: it discloses irreversibility and exactly which records are destroyed (balances, ledger, auto top-up rules), the 409 USER_HAS_HISTORY retention rule, the 404 case, a per-call 1 CRD charge that applies even on rejection while 429 is free, and that error results carry a request_id to quote to support.

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?

Six tight sentences, each carrying a distinct operational fact, with the identifier rule front-loaded and the error codes, cost model, and support workflow following in priority order. 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?

For an irreversible destructive tool with no annotations and no output schema, the definition supplies the failure modes, the cost model, the data-retention rule, and the support escalation path, leaving nothing an agent needs in order to call it safely or interpret a failure.

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; the description earns an extra point by explaining the precedence between user_email and external_id, which is not stated in the schema itself. The api_key, project_id, and x402_payment parameters are left entirely to their schema descriptions.

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 ("Delete an end user") plus the two identifiers used to target it, which unambiguously separates it from update_user, create_user, and delete_auto_topup among the siblings.

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 identification precedence (user_email checked first, external_id as fallback) and states the consequence of a user having swap history, so the agent knows when this call will be refused. It stops short of naming an alternative action for the history case.

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