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

Annotations already establish readOnly, idempotent, non-destructive behavior, so the bar is lower, and the description adds genuinely useful traits: rolling 12-month window, monthly refresh cadence, and first-party consumer-sourced data. It does not describe granularity resolution or latency beyond 'refreshed monthly', but that is a minor gap given the annotation coverage.

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?

One dense sentence with no filler; scope and freshness conditions are packed in efficiently. It is a noun-phrase fragment rather than a front-loaded verb statement, which slightly weakens scannability, but nothing is wasted.

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?

With only one optional parameter, full schema coverage, and no output schema, the description supplies the essentials: what the metric is, its source, its time window, and its refresh cadence. The only omission is the unit/format of the returned value (e.g., dollars), which is a minor gap for an agent calling it.

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% on the single state parameter, so baseline would be 3. The description adds meaning the schema does not: omitting the parameter yields the national aggregate, and supplying it narrows to exactly one state, clarifying the aggregation semantics of the optional field.

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?

Names a specific resource (median home value) with its data source and scope (national or one state), so an agent can tell it apart from the rate/lender siblings. It never states a verb and doesn't explicitly contrast with siblings like get_reference_series, so it stops short of a 5.

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 parenthetical '(national, or one state)' implies when to pass a state versus omit it, which is real usage guidance. However, there is no explicit when-to-use vs. alternative statement and no mention of prerequisites or when this data is unsuitable relative to the other value-series tools.

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