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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds value: it discloses that the return value is document ids for pages, and that results are static published references rather than computed per-borrower output. It does not mention how to resolve those ids (the fetch sibling) or any result-ordering behavior.

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 sentences, front-loaded with what is searchable, then the return type, then the scope caveat. Nearly every clause earns its place; the closing clause slightly restates the "published pages" idea already implied earlier.

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 correctly carries the burden of stating that results are document ids. For a simple two-parameter read tool this is close to complete; the only meaningful omission is guidance on what to do with a returned document id, which matters given the fetch sibling.

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 both parameters are documented with examples, so the baseline is 3. The description adds meaning beyond the schema by enumerating the entity classes a query can address (geography, lender, market rankings with optional loan/institution type), which helps an agent know what query strings are answerable.

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 names a specific verb (Search) and enumerates the exact resource classes covered: local mortgage-rate indexes by geography, lender profiles, lender rankings by market, and ranking methodology. It also draws a sharp boundary ("published reference pages, not priced scenarios"), which separates it from pricing-oriented siblings such as get_quote_estimate and from research_lender / find_lenders_in_market.

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?

Clear context is given for when this tool applies (finding published reference pages) and an explicit exclusion (it does not estimate a rate for a specific borrower). It stops short of naming the sibling to use instead for priced scenarios or for direct lender lookup, so the routing is implied rather than stated.

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