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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered by structured data. The description adds real context beyond that: the output is 'normalized listing rows' and the input must be a 'known property' (a prerequisite). It does not mention rate limits or auth, but for a read-only listing fetch those gaps are minor.

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 sentences, zero waste. The core purpose is front-loaded ahead of the alternative routing, which is the correct ordering for an agent scanning for the right tool.

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?

For a single-parameter read tool with an output schema and safety annotations already present, the description covers everything needed: what it returns, the input prerequisite, and how it differs from its siblings. Nothing required to call it correctly is missing.

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% and the single parameter is fully documented in the schema, so baseline is 3. The description's 'for a known property' reinforces that property_id references an existing property but adds no syntax, format, or sourcing detail beyond the schema.

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?

States a specific verb and resource ('Fetch Redfin's comparable listings') and the scope constraint ('for a known property'), plus clarifies the return shape ('as normalized listing rows'). An agent can distinguish this from redfin_property, redfin_estimate, and redfin_search without opening any schema.

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?

Explicitly names three sibling alternatives and the condition that selects each ('for the subject home's details', 'for its valuation estimate', 'to find listings'). This is exactly the routing guidance that prevents tool misselection.

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