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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds the valuable note 'Keyless' (no authentication required) and clarifies that it returns a listing of codes, going beyond annotation coverage. It does not contradict any annotation.

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?

Two sentences, each earning its place: the first states the core functionality with examples, the second gives the usage condition and routing to the sibling. The most important information is front-loaded, with zero 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?

For a simple list tool with no output schema and annotations covering safety, the description provides everything an agent needs: what it does, when to use it, what it returns (list of codes), and how it relates to the next step. No critical behavioral or usage detail is missing.

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% for the single optional 'subject' parameter, which already explains its purpose and gives examples. The description reaffirms the parameter's role ('know the subject area') but adds no new syntax or filtering details beyond the schema, so 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 states a specific verb (List), a precise resource (the 29 California codes), and gives concrete examples (PEN, VEH, LAB), making the tool's purpose unmistakable. It also explicitly distinguishes itself from the sibling ca_code_section by naming the sequencing, so an agent can tell them apart instantly.

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 description gives an explicit condition for use: 'Use when you know the subject area but not which code governs it'. It also names the alternative (ca_code_section) and the timing ('before calling'), leaving no ambiguity about when to invoke this tool versus its sibling.

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