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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds meaningful extra behavior: the payload is permission-scoped (it reports tools the account may NOT call, with an explicit 'everything else is allowed' rule) and flags the currently active account. It omits any auth/permission prerequisites for the caller.

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 tight sentences with zero filler. The resource and scope come first, and the alternative-tool routing is placed last as an actionable follow-up.

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 and a trivial input schema, the description carries the full burden and discharges it by enumerating the returned data (accounts, roles, denied tools, active account). Nothing an agent needs to call or interpret this tool is missing.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The schema is an empty, fully-described object consistent with the description.

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 every DIDWW account (customer) the authenticated user can act as') and enumerates the returned facts: roles held, tools not callable, and which account is active. This clearly distinguishes it from siblings like current_account and switch_account without needing to open any schema.

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?

Explicitly routes the mutation case to a named alternative: 'Use switch_account to change the active account.' It gives clear context for reading accounts, but does not directly contrast with current_account, which is the most confusable sibling.

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