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

The description adds useful behavioral context beyond annotations: provisional account, bounded, short-lived secret, no credits/API key before settlement. However, annotations already signal destructive and idempotent behavior, and the description does not clarify what, if anything, gets destroyed or reset, or how idempotency manifests.

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 sentences with no filler; the key action and precondition are front-loaded, and the operational constraints are compactly stated.

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?

It covers the main outcome and prerequisites, but for a 6-parameter start tool with no output schema it leaves parameter semantics and lifecycle behavior (idempotency, what to do with the secret/endpoint) underdescribed. Sibling names help, but the description itself does not fully equip an agent.

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?

With 0% schema description coverage, the description must compensate but only hints at policy acceptance and boundedness. It does not clarify max_amount_atomic, pack_id, label, idempotency_key, or policy_version, leaving most parameters underspecified.

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 an explicit verb+resource ('Start autonomous prepaid onboarding') and clarifies it applies only without an existing Mithrandir account. It names distinct outputs (onboarding secret, x402 endpoint) and a policy prerequisite, which differentiates it from siblings like onboarding_pay, onboarding_reconcile, and onboarding_status.

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 states the key precondition (no existing account), which is a clear when-to-use signal, and implies that status/pay/reconcile tools have different roles. It does not explicitly name alternatives or give a when-not-to-use list, so it falls short of full routing guidance.

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