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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds the output fields (zone code, setbacks, etc.) and U.S. coverage, but does not disclose potential limitations such as missing data for certain addresses or behavior for ambiguous inputs. This is a reasonable addition beyond annotations but not rich enough for a higher score.

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?

The description is concise and well-structured with clear 'USE WHEN' and 'RETURNS' markers. It packs purpose, usage triggers, and return list into a compact format with no fluff, ensuring every sentence earns its place.

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 one-parameter lookup tool with no output schema, the description adequately covers the purpose, when to use it, and the return values. It does not discuss error handling or data availability, but for a simple read-only lookup these are not critical. Solid coverage with minor gaps.

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?

The input schema has 100% coverage for the single parameter, with 'Full U.S. property address' already described. The description's mention of 'any U.S. property address' adds minimal semantic value beyond the schema. Baseline 3 is appropriate when the schema carries the full weight.

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 opens with a specific verb ('look up') and target resource ('zoning designation and development standards') for any U.S. property address. It also lists example user queries like 'what zone is this' and 'can I build a duplex here', which clearly distinguishes it from sibling tools such as check_flood_zone or get_buildability_score.

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?

The 'USE WHEN' section explicitly enumerates user intents and even includes 'or any question about permitted uses', giving clear context for when to invoke the tool. However, it does not explicitly mention when not to use or name alternative tools, so it falls short of a 5.

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