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

Annotations already declare read-only, non-destructive, idempotent, open-world. Description adds what return data includes (name, address, network, plug types, hours, last verified date), providing useful behavioral context. No contradictions.

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?

Three sentences, front-loaded with purpose. Each sentence serves a distinct purpose: action and scope, details of what's included, and exception/alternative. No wasted words.

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 presence of an output schema (as per context signals), the description sufficiently covers the tool's behavior and return fields. All parameters are documented in schema. No gaps.

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%, so the description adds little beyond what's in the schema. However, it mentions specific EV charging levels (Level 1/2/DC Fast) which relates to the fuel_type parameter, adding some marginal value.

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 the tool finds the nearest alternative fuel stations to a US location, listing fuel types and return fields. It also distinguishes from a sibling tool (openchargemap) for global EV stations.

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 states US-specific and provides an alternative for global EV stations. However, it doesn't contrast with other NREL tools like nrel.afdc.search or nrel.afdc.detail, which serve different purposes but are siblings.

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