opa_get_marine_fuels

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

No annotations are provided, so the description must cover behavioral traits. It mentions returning a table of port prices, but lacks details on data freshness, permissions, rate limits, or whether it only supports specific ports. Adequate but not exhaustive.

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?

Two sentences with no wasted words. Front-loaded with the main purpose, followed by usage conditions and output format. Ideal conciseness.

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 no output schema, the description states it returns a table of port prices, which is sufficient for a simple data retrieval tool. It covers key aspects: what, when, filters. Slightly vague on exact output structure.

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 description coverage is 100%, and the description adds context by stating filters are optional and providing examples (e.g., SINGAPORE, ROTTERDAM). This adds meaning beyond the raw 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?

The description clearly states it gets latest marine fuel (bunker) prices across major ports, listing specific fuel types and use cases. It distinguishes itself from siblings like opa_get_diesel_by_state or opa_get_price by focusing on marine fuels.

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 says 'Use when the user asks about bunker fuel, marine fuel, VLSFO, MGO, IFO380, or shipping fuel costs.' This provides clear context for when to invoke. Could improve by mentioning when not to use or alternatives.

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