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

With no annotations, the description carries the full burden and does disclose key behavioral traits: it returns a key with a fixed daily spend cap (default 1000 sats, max 5000) that cannot be raised later. It also notes 'no human required' and 'no signup form, no login.' It does not mention revocation, key format, or error behavior, but the most important constraints are covered.

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 but packs in purpose, usage condition, the cap limitation, and an alternative path. It is front-loaded with the main action and the condition for use. While slightly long, every sentence contributes necessary information with no redundancy.

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 one-parameter self-registration tool with no output schema, the description covers the core aspects: when to use, what it returns (a key with a capped spend), and the alternative for higher caps. It does not describe error scenarios or how the key is used, but given the tool's simplicity and the absence of an output schema, it is sufficiently complete for an agent to call it correctly.

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 already documents the parameter spend_cap_sats (default 1000, capped at 5000). The description adds that the cap is fixed and cannot be raised later, which is crucial for decision-making and goes beyond the schema's description. This additional context helps an agent understand the consequence of the parameter.

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 states a specific action: self-register for an operator API key, and explicitly contrasts with the scenario of already having a key. It is clearly distinct from the sibling tools, which all deal with skills or orders, so an agent can immediately tell what this tool does.

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 explicit when-to-use guidance ('Use this if you don't already have an api_key') and when-not-to-use guidance, pointing to a human signup for higher caps and ongoing monitoring. This leaves no ambiguity about when to select this tool versus the alternative.

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