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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: results are bounded and paginated, carry 2010 GEOIDs, a source hash, IRS authority provenance, and a 2010-vs-2020 boundary warning, plus the caveat that the corpus is an archived final cycle.

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?

Four tight sentences, each earning its place: purpose, mechanism, return shape, and usage caveat, with the identifying scope front-loaded in the first clause. It is dense but not padded; nothing reads as filler.

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 carries the return-value burden and discharges it by enumerating the returned fields and the GEOID-vintage warning. It does not state the no-filter default behavior, but the schema supplies defaults for limit/offset/response_format, so an agent has enough to call it correctly.

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% with all seven parameters documented, so the schema does the heavy lifting. The description restates the jurisdiction, county, and tract-type filters but adds no syntax, default, or format detail beyond what the schema already provides, which lands at the baseline 3.

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 opening question names the exact resource and scope: final 2018-cycle Qualified Opportunity Zone designations from the CDFI Fund workbook, with the searchable dimensions (tract, county, jurisdiction) spelled out. The 'Use for discovery' framing plus the explicit 2018-vs-2027 vintage scoping cleanly separates it from the sibling lookup/summarize/compare tools without ambiguity.

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?

It gives explicit when-to-use ('Use for discovery') and two concrete when-not-to-do conditions: don't query with a 2020-vintage GEOID and don't treat this archived final cycle as the still-unfinalized 2027 cycle. It stops short of naming the alternative siblings (lookup_designation, summarize_designations, compare_jurisdictions) that an agent should route to for other needs.

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