Get Value Estimate

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the return payload (point estimate, low–high range, comparable sales with attributes) and input alternatives (address vs lat/long, lookup_subject_attributes). While it does not mention side effects, permissions, or rate limits, the read-only nature is strongly implied by the word 'estimate' and the described output.

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?

At about 130 words across four sentences, the description is appropriately sized for a 9-parameter tool. Every sentence earns its place: purpose, sibling relationship, input options, return details, and use cases. It could be slightly more structured (e.g., bullet points), but it is not wasteful or redundant.

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 having no output schema and no annotations, the description is remarkably complete. It covers the tool's purpose, input flexibility (address or coordinates, optional attributes), the effect of lookup_subject_attributes, the return shape (point value, range, comparable sales), and practical use cases. This is more than sufficient for an agent to select and invoke the tool correctly in most scenarios.

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 has 100% coverage with detailed parameter descriptions, so the baseline is 3. The description adds semantic value by grouping optional subject attributes (propertyType, bedrooms, bathrooms, squareFootage) and explaining the shortcut of setting lookup_subject_attributes=true. This helps an agent understand the intended filing-in strategy beyond what the schema alone provides.

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 uses a specific verb ('Estimate the current SALE (market) value') and resource ('RentCast's AVM'), and explicitly positions itself as the sale-price counterpart to get_rent_estimate. This clearly distinguishes it from sibling tools like get_rent_estimate and get_market_stats.

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 provides explicit use cases: gauging what a property is worth, computing a rent-to-value / gross-yield ratio alongside get_rent_estimate, or sanity-checking a list price. It also names the closest sibling (get_rent_estimate) as a counterpart, giving an agent clear guidance on when to select this tool.

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