Create a metering account: returns a bearer token (shown once, we keep only a hash). Pass it as account_token on rent calls to build a usage ledger you can read back with account_usage. Optional — renting works without one.
| Name | Required | Description | Default |
|---|---|---|---|
| label | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses the one-time token display, the hash storage, and the ledger persistence. This adds important behavioral context beyond the schema, though it omits details like idempotency or error conditions, which are less critical for a registration tool.
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 two sentences with no unnecessary words. The primary action is front-loaded, and secondary details follow logically. It's concise and well-structured, though slightly run-on in the first sentence.
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 tool with a single optional parameter and no output schema, the description explains the return value, how to use it, and optionality. It doesn't cover failure modes or side effects beyond persistence, but the core usage is adequately covered.
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 schema provides 0% coverage (no parameter descriptions) and the tool description never mentions the 'label' parameter. An agent has no indication of what label does, whether it's meaningful, or if it affects account creation. This is a critical gap.
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?
Clearly states the action 'Create a metering account' with a specific resource and explains what it returns (bearer token) and how to use it. It also hints at the read-back mechanism via account_usage, making it distinct from other tools without needing to name them.
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?
Provides explicit context: the tool is optional ('Optional — renting works without one') and directs how to use the token on rent calls. It doesn't explicitly list alternatives, but the tool is unique in generating accounts, so the guidance is sufficient.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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