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

With no annotations at all, the description carries the full behavioral burden, and it does disclose something genuinely useful: the absence of KYC, email, and geographic restrictions. It still omits whether the call creates a persistent account, whether it is idempotent or repeatable, and what credentials or identifiers come back — material gaps for an account-creation 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?

A single front-loaded clause with a tight parenthetical list — no filler or hedging. It is arguably under-specified rather than over-written, but the structure itself is efficient and immediately parseable.

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 no annotations and no output schema, the description is the only source of truth about this tool, yet it never says what happens after the call or what the caller receives (account ID, keys, session handle). For an account-provisioning operation that omission is significant, and it also drops the 'futures' framing that the sibling set establishes.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The parenthetical correctly signals that no identity or locale inputs are needed, which is the only parameter-adjacent information that matters 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 names a specific verb and resource — 'Open an account' — with a parenthetical that clarifies it is frictionless onboarding (no KYC, no email, no geography). However, it never says what kind of account this is (the futures linkage lives only in the tool name) or what distinguishes it from siblings like futures_mandate, so an agent must infer the domain context.

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?

There is no guidance on when to call this versus futures_mandate or the other account-adjacent siblings, and no stated prerequisites or ordering (e.g., must an account exist before futures_trade or exchange_book). The parenthetical implies 'use this for zero-friction signup' but that is inference, not instruction.

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