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

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), lowering the bar. The description adds real value by disclosing partial-update/patch semantics ('Only the fields you pass are changed'), but says nothing about permissions, the single-use approval_id flow, or reversibility.

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?

Two short sentences with no filler; the trigger condition is front-loaded and the behavioral note follows. It is appropriately sized for the tool's scope.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. Combined with full schema coverage and the patch-semantics sentence, the description is sufficient for correct invocation, though the approval_id single-use requirement could be surfaced.

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 description coverage is 100% across 6 parameters, so the schema already documents each field including the status and in_debt enum-like values. The description adds only the general patch-semantics note, nothing per-parameter, so baseline 3 is appropriate.

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 frames the tool as triggering 'when a debt changed, like marking it paid off,' which conveys the resource and a mutation scenario, but never states the action verb itself (that lives only in the title). It is distinguishable from debts.delete only by inference.

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 provides an implied trigger ('when a debt changed, like marking it paid off'), which gives the agent some sense of when to invoke it. However, it names no alternatives among the debts.create/delete/list siblings and gives no exclusions or prerequisites.

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