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

Annotations only flag readOnlyHint=false and destructiveHint=false; the description goes beyond them by disclosing a rate constraint (one full standard-room visit per UTC day), a payment non-authorisation boundary, and post-registration text retention. Return payload and error behavior remain undisclosed, but the added behavioral context is substantive.

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?

Four short sentences, front-loaded with the dominant constraint, with no filler. A few clauses ("Received texts stay readable") are cryptic, but overall it is tight and skimmable.

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 6-parameter mutation tool with no output schema and thin annotations, the description covers preconditions and some side effects but omits what registration produces, how to pick a provider, and what agent_ref does. Adequate but with clear gaps given the low schema coverage.

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 17% (just account_ref), so the description must compensate, and it partially does: operator_authorized and accept_terms are explained via "operator authorisation" and "acceptance of the published terms," reinforcing "Reuse an existing account" for account_ref. It says nothing about agent_ref or the provider enum, leaving real gaps.

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 (register) and the resource context (an agent account), with preconditions attached. However, it never distinguishes this from sibling registration/account paths like eclypse_account or eclypse_guest_checkout, so the agent must infer the boundary.

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?

"Register only with operator authorisation and acceptance of the published terms" and "Reuse an existing account" give preconditions and a usage preference, which is real guidance. But there is no explicit when-to-use-this vs. an alternative sibling, and no statement of when NOT to call it.

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