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

Annotations already indicate this is a mutation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds the semantic distinction of being a real money-movement account, but does not disclose any additional behavioral traits such as side effects, reversibility, or required fields for a successful creation. Given the annotations cover the safety profile, the description adds modest value but could have mentioned that creation is a write operation that persists an account.

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?

The description is a single, well-crafted sentence that front-loads the core purpose ('Create a new bank account for the business') and immediately follows with the critical distinction ('Not a chart-of-accounts ledger account'). Every word earns its place, with no fluff or repetition. Excellent conciseness.

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 20 parameters and no output schema, the description provides minimal guidance on how to use the tool effectively. It doesn't outline typical creation flows, which fields are commonly required (even though none are marked required), or what the response contains. The schema descriptions are thorough, but the overall context for an agent—such as whether openingbalance is needed for reconciliation or how confirm interacts—is missing. The description could have summarized typical usage or mentioned that it returns the created account details. It is adequate but not complete for such a complex tool.

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 the schema already documents all 20 parameters in detail. The description does not add any parameter-specific meaning beyond the schema. Per the rubric, the baseline is 3 when the schema carries the load; the description adds nothing extra here, so a 3 is appropriate.

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 clearly states the verb (create) and the resource (bank account), and immediately distinguishes it from a chart-of-accounts ledger account, which is a key differentiator from the sibling tool create_account. This gives an agent precise understanding of what the tool does and what it is not.

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 explicitly notes 'Not a chart-of-accounts ledger account,' which steers the agent away from using this for ledger entries. It does not explicitly mention when to use this versus update_bank_account, but the verb 'create' makes that obvious. The context of reconciliation and cashflow also gives a usage signal. Slightly more explicit guidance on when to use it instead of other create tools would push it to a 5.

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