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

No annotations are provided, so the description carries the full behavioral burden, and it does not disclose authentication requirements, pagination/limit behavior, whether inactive or closed subaccounts are included, or ordering. It only hints at returned fields, which is thin for a list operation with no output schema.

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 sentence with no filler. However, 'with kind, currency, and balance' is terse and ambiguous about whether those are returned fields or optional filters, which slightly undermines the efficiency.

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, no output schema, and a 0%-documented parameter, the description should do more work. It omits pagination, result ordering, auth scope, and the treatment of closed subaccounts, leaving an agent unable to call it confidently beyond the trivial case.

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 the single required user_id, so the description must compensate. 'For a user' does establish that user_id selects whose subaccounts are returned, adding real meaning beyond the bare string type, but it says nothing about format (ID vs address) or whether it accepts the caller's own ID implicitly.

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 ('List') and resource ('subaccounts') scoped to a user, which clearly separates it from siblings like subaccount_create, subaccount_close, and subaccount_transfer. It also names the data surfaced (kind, currency, balance), though it never explicitly contrasts itself with those 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?

There is no statement of when to use this versus alternatives, no prerequisites, and no exclusions. The only signal is the implied 'read the subaccounts belonging to a user' framing, which is not enough guidance for a tool with three closely related subaccount siblings.

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