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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context by stating that 'unknown eligibility and unsupported stacking remain explicit,' informing the agent about how the tool handles incomplete data. 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, no filler. The first sentence conveys the core action and scope, and the second highlights an important behavioral guarantee. Front-loaded and efficient.

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 an output schema present and annotations covering safety, the description provides sufficient context for correct invocation. It explains the comparison dimensions and the handling of unknown information. Minor omission: it doesn't describe the output format, but that is covered by the output schema.

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 coverage is 100% with both parameters (offers and facts) fully described. The description adds value by connecting these parameters to the comparison dimensions (value, access requirements, eligibility, etc.), making it clear how the inputs drive the output beyond raw schema definitions.

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 purpose: comparing startup credit or deal offers, with a clear scope (two to ten) and the attributes compared (value, access requirements, eligibility, freshness, evidence). It clearly distinguishes this from sibling tools like search_offers by focusing on side-by-side comparison rather than search.

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 clear context for when the tool is appropriate: when you need to compare multiple offers side by side. It does not explicitly mention when not to use it or provide alternative tools, but the scope is unmistakable and aligns with the tool name.

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