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

The annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds context by naming the data source (Federal Reserve Student-Loan Data Portal), the history start year (2007), the returned metrics, and the quarterly update frequency. These details go beyond the annotations, though it omits any mention of rate limits or the effect of the optional days parameter on the output, hence not a 5.

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 a single information-dense paragraph of two sentences. The first sentence delivers the core purpose and output contract; the second provides trigger conditions and update cadence. There is no redundancy with the schema or filler content.

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?

No output schema exists, but the description names all five return values, giving a complete expected response contract. It also includes the data source, history range, update frequency, and the exact scenarios where the tool is relevant. The only missing detail (how the optional days parameter interacts with the output) is already covered by the schema, so this does not detract.

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 description coverage is 100%: the only parameter, days, has a thorough description explaining the optional daily history series and the Gold tier requirement. The description itself does not discuss parameters, but since the schema fully covers them, a baseline of 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 opens with 'Returns a 0-100 US student-loan refinance exhaustion score' immediately stating the verb, resource, and scope. It enumerates the exact output fields (exhaustion_score, momentum, default_velocity, confidence, methodology_version), making the tool's function unmistakable and distinct from the many numbered siblings.

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 explicitly states 'Call when the user asks about...' followed by a list of user intents and downstream use cases (underwriting tightening, loss provisioning, consumer-ABS positioning). It also notes the quarterly update cadence, giving the agent timing expectations.

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