mah_list_billing_accounts

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

Annotations already establish readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful behavioral detail beyond that: results are grouped into three named categories, and amounts come back as formatted display strings rather than numerics, which prevents an agent from doing arithmetic on them.

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?

Two sentences, zero filler. The grouping taxonomy comes first and the amount-format caveat second, which is the right priority order for an agent that will parse the results.

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 output schema, the description carries the burden of describing the return value, and it does so at a useful level: the three groups plus the formatted-string caveat. It stops short of pagination, empty-state, or ordering behavior, which leaves a small but real gap for a list 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 both the raw debugging flag and the compact/full view enum are fully documented in the schema, including the projection behavior. The description contributes nothing about either parameter, so the baseline 3 applies.

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 -- list billing accounts -- and adds the grouping taxonomy (outstanding, zero-balance, guarantor-authorized) that tells the agent what it actually gets back. No sibling competes for billing accounts, so explicit differentiation is unnecessary, but the description doesn't clarify that this is the only billing reader.

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?

Usage is only implied: an agent needing billing balances would infer this tool, and there is no competing sibling to route away from. However, the description never states when to call it, that it requires an authenticated/active patient context, or what it does when no balance is due -- guidance that would matter for a patient-scoped reader.

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