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

No annotations are provided, so the description carries the full behavioral burden. It does disclose the accepted input forms (listing URLs or raw ZPIDs) and the returned data set, which is useful, but says nothing about rate limits, batching of multiple URLs, error behavior on bad ZPIDs, or authentication. Adequate but clearly incomplete for a no-annotation tool.

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, no filler. The capability and its returned fields come first, and the chaining relationship to search_zillow is placed last as the routing cue.

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, so the description usefully enumerates the returned fields in its place, and it names the upstream tool. It stops short of covering rate limits or failure modes, but for a one-parameter read tool the core information an agent needs is present.

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 single parameter is already documented as "Zillow property URLs or raw ZPIDs"; the description's "from listing URLs or ZPIDs" merely restates it. No added syntax, format examples, or batch-limit guidance, so the baseline 3 applies.

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 (Fetch) and resource (Zillow property data) and enumerates the exact payload an agent gets back: price history, tax history, school ratings, HOA fee, year built, Zestimates, photos. It also distinguishes itself from the sibling search_zillow by declaring that it chains off that tool's output, so an agent can route correctly without opening either 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?

"Chains off search_zillow output" gives clear usage context: call this after search_zillow to expand a listing into full details. What is missing is any when-not guidance (e.g. don't call with non-Zillow URLs, batching expectations), but the positive routing signal is unambiguous.

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