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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the meaningful scoping detail that these are current *national* promotions, implying location-level offers are out of scope, but it says nothing about update cadence, coverage, or any caveats about the legal terms returned.

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?

A single front-loaded sentence that identifies the source, the scope, and the returned fields with zero filler. Every clause 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-argument retrieval tool with an output schema, the description is essentially complete — the output schema handles return-value structure, and the description confirms the domain. The only missing piece is explicit guidance on its limits (national-only, no filtering).

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 takes zero parameters, so the baseline is 4. The description correctly adds nothing about parameters because there are none to document.

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 names a specific resource and scope — Sonic Drive-In's current national promotions — and even enumerates the fields each deal carries (headline, description, legal terms, CTA link, creative image). It is clearly distinguishable from siblings like sonic_menu, sonic_item, and sonic_locations. It lacks an explicit verb, so it falls 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?

Usage is implied rather than stated: an agent can infer this is the tool for promotional/deal data, and there is no sibling offering promotions to conflict with. However, it gives no when-to-use framing, no exclusions (e.g., that these are national and not location-specific), and no alternatives.

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