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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description's safety profile is covered. The description adds useful context that the tool follows CDR standards and requires a valid Data Holder Brand ID obtained via GetDataHoldersByCategory. This goes beyond the annotations without contradicting them, though it doesn't disclose potential errors or rate limits.

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 sentences with no filler. The first sentence states the purpose and standard, the second provides a key usage prerequisite. It is front-loaded with the core function and well-structured.

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 read-only tool with two parameters and no output schema, the description covers the essential purpose and a crucial prerequisite. It does not mention the singular vs. plural distinction (get_products_eligibility), but the title and wording imply singleton use. Given the tool's simplicity, the description is sufficiently complete.

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%, so both parameters are documented in the input schema. The description adds a small extra hint that the dataHolderBrandId comes from GetDataHoldersByCategory, but productId semantics are essentially the same as the schema. Given high schema coverage, the description adds marginal value, earning a baseline 3.

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 the tool returns the eligibility of a specific banking product, identified by Product ID, and references the CDR Banking standards (BankingProductEligibilityV2). It distinguishes from sibling tools by focusing on eligibility rather than features, fees, or rates, and the title reinforces the 'Single' product scope.

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 provides a clear prerequisite: 'Use GetDataHoldersByCategory first to obtain a valid Data Holder Brand ID.' However, it does not explicitly mention when to avoid this tool in favor of alternatives (e.g., get_products_eligibility for multiple products) or contrast with other singular product tools like get_product_features. Guidance on selection is partially implied but not explicit.

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