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

Consistent with readOnlyHint/openWorldHint, and adds context the annotations cannot convey: static vs live data, per-region provenance (US DOE AFDC for US/Canada, OSM elsewhere), and an explicit paid-call model ($0.002 USDC via x402, unsuccessful calls not billed). The cost and billing semantics are exactly the kind of behavior an agent needs before invoking.

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?

Front-loaded with purpose and result shape, then source coverage, then cost — every clause carries information. The heavy parenthetical enumerations make the first sentence dense, but nothing is redundant.

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?

With an output schema present and 100% parameter coverage, the description only needs to add scope, data provenance, freshness limits and billing — and it does all four. An agent has everything required to call this correctly and interpret the result.

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 lat/lon ranges, limit (1-50, default 10) and radius (100-10000 m, default 2000) are already fully documented in the schema. The description adds no parameter-level detail such as units for lat/lon strings or how radius interacts with limit, so the baseline of 3 applies.

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?

States a specific verb and resource ('EV charging locations near a point') plus the exact return shape (OCPI 2.2 Location → EVSE → Connector with connector standard, power type, max power, operator, hours, status). No sibling tool covers charging infrastructure, so the agent can select it unambiguously.

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?

Clearly signals the use case (proximity search around a coordinate) and the important exclusion that this is static directory data with no live availability. It also says which source applies in which region, which shapes expectations. It stops short of naming an alternative tool for live status, but no such sibling exists.

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