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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds useful auth context beyond annotations: which actions require no key versus any key, that whoami returns the API base and key prefix, and that omitting action runs briefing.

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 front-loaded with 'Start here' and then uses a compact action list where each entry earns its place. It is slightly dense with parenthetical key requirements, but there is no filler.

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?

For a zero-required-parameter dispatcher with no output schema, the description is nearly complete: it enumerates all actions, states auth needs, describes brief return content (API base, key prefix, strikes, counts), and gives the default behavior. Error behavior and output structure beyond the summary are not covered, but they are not essential here.

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%, and both parameters have enums and inline descriptions covering defaults and role fallback behavior. The description restates the action list and key requirements but does not add syntax or format details beyond what the schema already provides.

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 clearly frames the tool as a starting point and enumerates its five actions (briefing, whoami, me, standing, openapi) with their resources. It is specific about what each action does, though it does not explicitly distinguish itself from siblings like commercebook_account_start or commercebook_capabilities.

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?

It gives clear context for each action, including key requirements (briefing with no key, whoami/me/standing/openapi with any key) and default behavior when action is omitted. It stops short of naming alternatives or exclusions, but the per-action conditions are explicit.

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