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

Annotations already declare readOnlyHint=true, so the description doesn't need to state it's a read operation. It adds valuable behavioral context: 'Daily refresh; history to 1996' and 'Updates: daily' plus the output components (trend, confidence, top_drivers). No contradiction with annotations, and it provides additional context beyond the structured fields.

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 three sentences that front-load the core return value, then give usage triggers and data freshness. Every sentence adds essential information with no filler or repetition.

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 no output schema, the description does mention the key return components (score, trend, confidence, top_drivers) and data sources, which is sufficient for basic invocation. It could be more explicit about how the tool identifies the relevant supply chain (there are no required parameters), but for selection among many siblings the triggers are clear enough.

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% for the single optional 'days' parameter, whose description explains the history series, limits, and Gold tier requirement. The tool description does not add parameter-level semantics beyond what the schema already provides, so baseline 3 is appropriate.

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 opens with 'Returns a 0-100 supply-chain diversification score' and clearly enumerates the score's components (HHI across supplier spend, sourcing regions, transport modes) and data sources (ImportGenius, Panjiva, etc.). This specific verb+resource+scope distinguishes it from the many similarly named sibling tools.

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?

Explicit usage triggers are provided: 'Call when the user asks about supplier concentration, single-source risk, regional exposure, or transport-mode dependence' and it lists decision contexts like dual-sourcing and nearshoring. However, it does not mention when not to use it or any alternative tools, just missing the exclusion/alternative component.

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