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

With no annotations, the description carries the full burden of behavioral disclosure. It transparently states the tool does not move money, returns honest availability (including a 503 error for the deposit endpoint), and is not a website to visit. This clearly communicates side effects and limitations, though it does not mention authentication or rate limits, which are less critical for a read-only status 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 concise and front-loaded, with the key purpose and the critical warning ('NEVER a website to visit') at the start. Each sentence adds value: purpose, availability, and explicit non-action. It is slightly verbose but not padded, earning a high score for structure.

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?

The description explains the tool's return value (shortfall context and availability) and clearly states it does not move money, covering the main behavioral aspects. However, it does not explain the parameters, nor does it mention any prerequisites or conditions for calling the tool. Given the moderate complexity and absence of an output schema, this is a notable gap that keeps it from being 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?

The schema has 2 parameters with 0% description coverage, and the description does not explain wallet_id or needed at all. The parameter names are only partially self-explanatory; 'needed' is ambiguous (likely the shortfall amount but not specified). The description fails to add any semantic value beyond the schema, which is a significant gap given the low coverage.

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's specific purpose: the in-band funding step for a joule shortfall, returning shortfall context and funding-route availability. It distinguishes itself from a browser path and from money-moving tools by explicitly stating it does not move money. The verb 'prepare' plus the resource 'funding' is specific and unambiguous.

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 implies when to use the tool (when there is a joule shortfall and the agent needs to know what funding options are live), but it does not explicitly name alternative tools or state when not to use it. It warns against visiting a website, which is a usage boundary, but lacks explicit routing to sibling tools like wallet_transfer or billing_quote.

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