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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses critical behavioral details: the data cutoff (November 2023), missing units, absence of draft/lock-status data, and the pricing model including that failed calls are not charged. This is rich, actionable transparency.

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 front-loaded with the core purpose and source, then efficiently layers caveats (file end, units, exclusions) and pricing. Every sentence earns its place and no information is redundant.

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 a simple tool with one well-documented parameter, an output schema, and relevant annotations, the description covers all necessary context: data provenance, temporal scope, unit ambiguity, exclusions, and cost. Nothing an agent needs for correct invocation is missing.

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 single parameter 'weeks' is fully described in the schema (range, default), and the description adds no further semantic detail about it. With 100% schema coverage, the baseline 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 specifices exactly what the tool returns: weekly downbound grain barge rates on the Upper Mississippi from a named USDA dataset. It distinguishes itself from all siblings by focusing on a unique data source and geography, with no ambiguity about the resource.

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 clear context for when the tool is applicable (weekly grain barge rates) and explicit exclusions (no draft or lock-status data, data only through November 2023). It does not name a specific alternative tool to use instead, but no direct sibling offers the same data, so the guidance is sufficient for selection.

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