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

Annotations cover read-only and open-world, and the description adds two things they cannot: the operation costs 1 credit, and fields are returned only 'where published,' so partial results are expected. That is real behavioral context an agent needs before spending credits, though response shape and failure behavior on a bad/inaccessible URL remain unstated.

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?

Three short, front-loaded clauses with no filler; the field list and credit cost each carry information. The opening sentence mostly restates the title ('Zillow agent profile'), a small redundancy, but the rest is efficient.

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 no output schema, the description usefully names the returned fields and flags partial availability, which is good compensation. However, the undocumented `cache_max_age` parameter and no guidance on URL validity or error cases leave gaps for a paid, open-world fetch.

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?

At 50% schema coverage, the schema already documents the required `url` with a format example, so the description adds nothing there. The optional `cache_max_age` parameter is undocumented in both places, and the description does not compensate, so it sits at the baseline.

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 verb+resource (fetch a public Zillow agent/team profile) and enumerates returned fields (brokerage, license, rating, review count), which tells an agent exactly what this yields. It does not explicitly distinguish itself from the closest sibling, redfin_agent, but the Zillow naming plus the field list make the domain unambiguous.

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?

No statement of when to use this versus zillow_property, zillow_search, or redfin_agent, and no prerequisites beyond what the schema implies. The only implicit guidance is the required profile URL, which comes from the schema rather than the description.

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