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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals a critical behavioral trait: when the balance reaches zero, patron top-ups cannot be certified and the operator must call purchase_credits. It also notes the operation is free. However, it does not explicitly state that it is read-only, though the verb 'check' implies it.

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 extremely concise, consisting of four sentences, each adding essential information. The first sentence states the high-level purpose, the second describes the return value, the third explains the consequence of a zero balance, and the fourth clarifies ownership. No wasted words.

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?

Given the tool has no parameters and an output schema exists, the description provides sufficient context: it explains the return value (sats available), the significance of the balance, and the next step if zero. It could marginally improve by explicitly stating it is a read-only operation, but overall it is complete.

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?

There are zero parameters, so the baseline is 4. The description does not need to add parameter information since none exist. It correctly avoids mentioning parameters.

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 clearly states the tool checks the operator's tax balance at the Authority, specifying it returns sats available for certifying patron credit purchases. It distinguishes itself from sibling tools like excalibur_check_balance by explicitly noting this is the operator's own funding, not a patron balance.

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?

The description explains when to use this tool: to check sats available for patron credit certification. It also provides guidance on what to do when the balance reaches zero (call purchase_credits). However, it does not explicitly mention when not to use it or provide alternatives, leaving some room for improvement.

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