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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful behavioral context: return fields (USD price, unit, observation period), the data source, and the unusual cryptographic settlement receipt. No contradiction with annotations.

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 purpose and return values, then covers source and attestation. The only waste is the redundant pricing statement: '$0.02 atomic' and '$0.02 USDC per call' say essentially the same thing twice.

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 single-enum-parameter read-only tool with no output schema, the description is complete: it names the commodities, return fields, source, and cost model. An agent has enough to select and invoke the tool correctly without further inspection.

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 one parameter is fully enumerated in the schema, and the description simply repeats the same commodity list. It adds slight context about what is returned per commodity but does not substantially deepen the meaning of the parameter beyond the enum.

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?

States a specific verb and resource: retrieving a spot agricultural commodity price from FRED/IMF series for five named commodities. This is clearly distinguishable from broad siblings like get_commodity_benchmark and commodity-specific peers like get_copper_price_benchmark.

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?

Explicitly names intended use cases: crop hedging, food cost modeling, and trade exposure agents. It does not explicitly contrast with get_commodity_benchmark or state exclusions, so it stops short of a 5.

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