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

With no annotations provided, the description carries the full burden. It discloses the key model (one credential, one account), guarantees exactly one account is returned, notes pagination has_more is always false, and mentions the authorization object with allowed_tasks. This goes well beyond a generic 'list accounts' description, though it stops short of discussing side-effect-free behavior explicitly.

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 organized into clear sections—purpose, when to use, returns, and example. It is longer than average but every section adds useful context, and the key constraint (one key = one account) is front-loaded at the top.

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?

There is no output schema, so the description appropriately explains the return shape: account objects with fields plus authorization and pagination behavior. It covers the main workflow and includes a concrete example. Missing details like sandbox semantics and the account filter are covered in the input schema, so the overall picture is largely complete.

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 coverage is only 60%, and the description does not compensate for the undocumented context and pagination input parameters. The example with status adds little beyond the schema's own enum description, and the description never explains the account filter object or what pagination parameters mean for a tool that always returns one account.

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 opens with a specific verb and resource: 'List the accounts this credential can transact on.' It then clarifies the account model—one API key equals one account—so an agent immediately understands exactly what this tool returns and how it differs from other list_* tools.

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 'WHEN TO USE' section explicitly lists clear use cases: discovering account_id before account-scoped calls, checking account status before buying, and introspecting allowed tasks. It does not name alternative tools or state when not to use it, but the context is strong enough for an agent to select it correctly.

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