resize_account

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

Annotations already declare readOnlyHint, idempotentHint and a closed-world scope, so safety and repeatability are covered. The description adds genuinely useful context not in the annotations: the operation is free (relevant given the pricing and credits_balance siblings) and the exact output shape via examples. It omits what happens when `digits` is shorter than the current code length or when the input has no separator, which are the real behavioral questions for a padding tool.

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?

One short sentence plus two compact examples, with the core action front-loaded and no filler. The examples earn their place by encoding behavior that the prose would otherwise need several sentences to convey.

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?

Because an output schema exists, the description needn't explain return values, and the examples make the mapping fairly clear. For a simple read-only transform this is close to adequate, but the undocumented `split` parameter and the unstated truncation behavior leave an agent guessing on a non-default call.

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 0% for all three parameters, so the description carries the full burden and only partially meets it. The example '4300001 (7) -> 43000001 (8)' implicitly reveals that `digits` is the target length, but the optional `split` parameter (default 4) is never explained — the '430.1' example hints it governs separator handling without stating so.

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 ('Resize or expand a Spanish subaccount code') and backs it with two concrete transformation examples, so the agent knows the tool reformats/pads an accounting code rather than validating or converting a journal. It stops short of 5 because 'resize or expand' is slightly ambiguous about whether shrinking is permitted, and no sibling is named as the alternative.

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 statement of when to reach for this tool versus siblings such as detect_format or validate_journal, and no prerequisites (e.g., must the account already exist, must the format be Spanish). The only usage signal is implicit in the two examples.

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