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

Annotations already indicate read-only, idempotent, non-destructive. The description adds significant behavioral detail: null handling with explicit price_status='source_missing', no unit mixing (mixed-unit aggregations are null), immutable capture vintages with as_of, and SHA-256 source evidence. These go far beyond the annotations and inform correct usage.

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 dense but well-organized: an initial summary, then atom-specific details, filtering, and caveats. Every sentence contributes a distinct constraint or behavior. The length is justified by the tool's complexity, and the front-loaded first sentence delivers the core purpose immediately.

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 the tool has two distinct data series with different units, null semantics, revision handling, and evidence requirements, the description covers all critical aspects. An output schema exists to document return structure, so the description need not repeat that. It explains unit-mixing pitfalls, proxy exclusion, and source-verification features fully.

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 input schema is a generic 'params' object with additionalProperties and 0% coverage. The description compensates fully by defining the two atom values, listing filterable fields (date, date_from/date_to, series, state, price_status, as_of), and giving a concrete example: {"atom":"state_electric_power_monthly","state":"TX"}. This is essential meaning not available in the 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 opens with a specific verb+resource statement: 'Query verified EIA natural-gas price records from two public series.' It then distinguishes the two atoms (henry_hub_daily_spot and state_electric_power_monthly) and gives concrete examples, making it clear this is a data-returning query tool rather than the sibling describe tool.

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 detailed guidance on when to use each atom, how to filter (date, state, series, price status), and explicitly states what the tool does not do (no proxies, no heat rates, no unit conversion). It does not explicitly mention the describe sibling for metadata, but the usage boundaries are well-defined.

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