OilPriceAPI

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

With no annotations, description carries full burden. Discloses return structure: 'grouped by category (oil, gas, coal, refined products, metals, forex) with 24h changes.' This explains what the tool produces beyond the schema. Lacks data freshness/source details, but covers the essential behavioral output.

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?

5 sentences, zero waste. Front-loaded with purpose, followed by usage context, return behavior, parameter hint, and sibling alternative. Each sentence earns its place with no redundancy.

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?

Adequately covers the single optional parameter and explains return values (grouping and 24h changes) despite lacking an output schema. Could be improved with data source or latency information, but sufficient for a simple overview tool.

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% (category parameter fully documented with enum and description). Description states 'Supports filtering by category,' which confirms functionality but adds minimal semantic value beyond the schema. Baseline score appropriate for high-coverage schema.

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?

Specific verb 'Get' + resource 'current prices for all tracked energy commodities' + scope 'in one call'. Explicitly distinguishes from sibling opa_get_price: 'For a single commodity, use opa_get_price instead.' Clear and actionable.

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 when-to-use: 'Use when the user wants a broad market snapshot or asks about overall energy prices.' Explicit alternative named: 'For a single commodity, use opa_get_price instead.' Provides clear decision criteria between broad vs. specific queries.

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