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

The description discloses the score range, methodology, data sources, monthly cadence, and output fields. It adds useful behavioral context beyond the readOnlyHint annotation, such as the fact that updates are monthly and the score is based on equal-weight z-scores. It does not describe potential edge cases or response formatting, but the annotation already covers safety.

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 dense but efficient: the first sentence packs the score scale, methodology, data sources, output fields, and temporal scope; the second sentence gives targeted use cases and update frequency. No filler or repetition of schema details.

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?

There is no output schema, but the description compensates by enumerating the returned fields (trend, confidence, health_label, top_drivers, rate/delinquency percentages) and defining the score's meaning. It also explains when to use the tool and how often data updates, making the tool self-sufficient for an agent.

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%, and the schema already fully documents the optional days parameter, including the history behavior and Gold tier requirement. The description adds monthly frequency context but does not meaningfully extend the parameter semantics beyond what the schema provides. 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 opens with a specific action and object: 'Returns a 0-100 mortgage-market stress score' with an explicit formula, time range, and update frequency. It also lists the exact output fields, making the tool's purpose unmistakable even among opaque sibling names.

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 when to call the tool: when the user asks about mortgage market health, mortgage rates, delinquency trends, or housing credit stress, and for timing LTV/underwriting decisions. It provides clear use-case triggers but does not describe when not to use it or name alternative tools.

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