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

Beyond the readOnlyHint annotation, the description discloses the calculation method (weighted z-scores of truck freight PPI YoY and diesel 4-week change), the 36-month window, data source (FRED), frequency (monthly since 2007), and update cadence. It also transparently notes that the optional history feature requires Gold tier and otherwise returns the current snapshot. This is rich behavioral context with no contradictions.

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 efficient sentences. The first sentence fronts the return value and composition, the second gives concrete use-case triggers and update cadence. Every clause carries information; no wasted words.

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?

Given there is no output schema, the description usefully enumerates the return fields (score, trend, confidence, top_drivers, component z-scores). It also explains the index's construction, data source, and update frequency. It does not define interpretation benchmarks for the 0-100 scale, but for a data-index tool this is sufficient. A 4 reflects strong coverage without overreaching.

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 only parameter, `days`, is already fully described in the schema (optional, range 1-1825, returns a historical series, requires Gold tier). The description adds no additional parameter-level nuance, so with 100% schema coverage the baseline score of 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 a specific verb ('Returns') and a clear resource: a 0-100 US freight and logistics cost pressure index. It names the exact outputs (score, trend, confidence, top_drivers, component z-scores) and the underlying methodology, making it unmistakably distinct from any sibling tool.

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 explicitly lists when to call the tool: 'when the user asks about freight rates, trucking costs, diesel prices, shipping cost inflation, or supply-chain margin pressure, or when timing carrier contract renegotiations, fuel surcharge requests, or margin-risk alerts.' This is strong when-to-use guidance, though it stops short of naming alternatives or exclusions, so it earns a 4 rather than 5.

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