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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, but the description adds crucial behavioral context beyond this: 'Nothing is repaid by this tool: no key, no transaction.' This sets accurate expectations about side effects and required inputs. It also details the two return links and their modes, which is not captured by annotations.

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?

Three sentences, front-loaded with the core action (preparing repayment), followed by the return links and critical no-action disclaimer. Every sentence earns its place with no fluff.

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?

Despite no output schema, the description fully explains what the tool returns (two links for repayment) and clarifies that no transaction occurs, which is essential for correct invocation. It also covers the required agent_id via schema. The definition is complete for an agent to use 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?

Schema coverage is 100%, so the schema already documents the single agent_id parameter thoroughly. The description does not add syntax or format details beyond what the schema provides, but its explanation of the overall flow implicitly reinforces the parameter's purpose. Baseline would be 3; the extra context about loan listing and repayment modes warrants a slight bump.

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?

States a specific verb and resource ('Prepare the repayment of a Priors agent's open loans') and clarifies it returns links rather than executing repayment. Distinguishes from the sibling request_borrow by being the repayment counterpart.

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?

Explicitly states when to use it: 'Use it when the user wants to repay the loans of an agent they own.' It also gives clear alternatives for how to complete the repayment (Go mode vs Builder mode) with URLs and conditions.

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