Get US Natural Gas Hub Prices

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

The description explains the two modes (with/without hub), return contents (basis and history), and adds a critical caveat about varying hub history depth. It also discloses the paid-plan requirement. These details go well beyond the readOnlyHint and openWorldHint annotations, without contradicting them.

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 efficient and well-structured: it opens with the core purpose, follows with usage guidance and hub enumeration, and then explains behavior and prerequisites. No sentence is wasted, and all necessary information is present.

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 read-only, optional-parameter tool with no output schema, the description fully covers behavior in both call variants, the data depth caveat, and access requirements. It is complete for an agent to select and invoke the tool correctly without additional context.

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?

Although the schema descriptions are complete (100% coverage), the description adds value by clarifying the 'past' parameter's format with examples (30d, 6m, 1y) and reiterating that it only applies when a hub is provided. This enriches the parameter semantics beyond the schema alone.

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 states a specific verb+resource ('Get US physical natural gas hub prices as basis to Henry Hub') and explicitly lists the hub identifiers, clearly distinguishing this tool from siblings like opa_get_price or opa_get_futures. The scope (natural gas hubs) is precise and unambiguous.

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?

It explicitly says 'Use when the user asks about regional gas prices or hub basis' and names the relevant hubs, giving clear context. However, it does not mention when not to use this tool or name alternative tools for non-hub commodities, so it stops short of a full 5.

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