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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the behavioral context that this is a reference/enumeration tool for state codes usable as filters. It doesn't add much beyond that, but with annotations covering the safety profile, a 3 is appropriate.

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?

One sentence, zero waste, and the purpose is front-loaded. Every word 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 zero-parameter, read-only enumeration tool with annotations covering safety, the description is nearly complete. It could mention whether the output includes both codes and names in a specific format, but the description already says 'USPS state codes and full names'. No output schema exists, but the description sufficiently conveys what the agent will get.

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 tool has 0 parameters, so the schema provides no parameter semantics. The description adds meaning by explaining the output's purpose (usable as the `state` filter in other tools). With 0 params, baseline 4 is correct.

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') and resource ('USPS state codes and full names'), and clarifies the purpose: usable as the `state` filter in other tools. It doesn't explicitly distinguish from siblings, but the resource is distinct enough that an agent can tell it apart from get_project, list_causes, etc.

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 implies when to use this tool: when you need valid state filter values for other tools. It doesn't explicitly name alternatives or exclusions, but the context is clear. A 4 is appropriate because it gives clear context without explicit when-not-to-use guidance.

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