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

With no annotations, the description carries the full burden and does so well: it discloses the return value (a bearer token), its lifecycle (reusable until token_expires_at, 1 year default, not single-use), session-internal auto-remembering, raw-HTTP persistence caveats, prerequisites (nothing), and a typical error (422). This is rich behavioral context beyond a bare 'create account'.

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?

Front-loaded with the core action and inputs, then token-handling guidance. It is longer than average but most sentences earn their place (token reuse, curl persistence, error recovery). Minor redundancy around the token not being single-use keeps it from a 5.

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 registration tool with no annotations and no output schema, the description covers the crucial account-creation semantics, token lifecycle, session behavior, and error recovery paths. An agent has everything needed to call it correctly and handle the aftermath.

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 25% (only token_ttl_days documented), so the description must compensate; it names the three required fields and adds real meaning to email (must be a controlled, non-reserved address) and reinforces token_ttl_days range (1-1825, default 365). It could say more about first/last name constraints, but it meaningfully supplements the sparse schema.

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 ('Create a NEW EQVPS customer account') and names the inputs (first_name, last_name, email). It is clearly distinguishable from siblings like login, refresh_token, and set_password, which it references directly.

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 says when NOT to use it ('Never call register_account again to "get a new token": that creates another, empty account') and routes the agent to alternatives (refresh_token before expiry, login/saved token on 422 email already registered). The when-to-use-vs-alternative guidance is unusually thorough.

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