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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior, so the bar is lower. The description adds the important behavioral boundary that the tool performs screening only and does not produce a final eligibility determination, which is meaningful beyond the annotations. This gives agents a clear sense of the tool's scope and limitations.

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 two short sentences with no filler. The first sentence states the core action and input, and the second delivers a crucial caveat. 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 simple one-parameter, read-only tool with annotations and an output schema, the description covers the essential purpose and limitation. It does not mention alternative tools for final determination, but sibling names are provided separately in the context, so an agent could infer where to go next. Overall, the description is nearly complete for its complexity.

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 schema has a single 'zip' parameter with no description and 0% schema_description_coverage, so the description must compensate. The phrase 'based on ZIP-level facts' clarifies that the zip parameter refers to a geographic zip code and that results are scoped to that level, adding some meaning beyond the name. However, it does not explain the expected format, source of facts, or edge cases, so compensation is partial.

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 clearly states that the tool screens potentially claimable programs based on ZIP-level facts, which is a specific action on a specific resource. It also distinguishes the tool from a final eligibility determination, though it does not explicitly name a sibling tool for that purpose. This makes the purpose clear but slightly under-differentiated from siblings like get_program_status.

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 phrase 'This is screening only, not a final eligibility determination' implies that this tool should be used for preliminary checks rather than authoritative answers, but it does not explicitly state when to prefer this tool over get_program_status or another sibling. The usage context is implied rather than spelled out.

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