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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds meaningful behavioral disclosure beyond that: 'The response says whether the jurisdiction was researched, has a published guide, or only the state baseline is known; report that honestly.' It also discloses that each item comes with citations and that the published guide plus baseline are included. This is rich, non-obvious behavior that helps the agent set user expectations.

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?

Every sentence earns its place: scope/content, usage triggers, output/fallback behavior, and an example. The core purpose is front-loaded. The dense first sentence and the minor 'A-du guide' typo keep it from a perfect 5.

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 burden of explaining what the response contains, and it does so: ordinance status, state standards, fee notes, contacts, plan programs, citations, guide, and baseline. It also covers the uncertain-jurisdiction case. It does not specify error behavior or what happens with an invalid jurisdiction, which keeps it from a 5.

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%, so the schema already documents both parameters. The description adds only a usage example ('{"jurisdiction": "Cerritos"}') and the California scope, not new parameter semantics. The baseline of 3 is appropriate.

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+resource+scope: 'The rules that govern building or renting an ADU in a named California city or county.' It then enumerates the kinds of rules returned. It does not explicitly distinguish itself from the sibling ask_adu or search_plans, so it stops short of a 5.

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 concrete trigger phrasing: 'Use for any "can I build", "what are the rules", "do I need parking", "can the city require" question.' This is clear when-to-use guidance. There is no when-not-to-use or alternative routing, so it is a 4 rather than a 5.

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