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

Goes well beyond the readOnly/openWorld/idempotent annotations by disclosing the x402 payment model, exact cost (0.005 USDC per successful call), blockchain (Base), and that errors are free. This is critical pre-invocation context an agent cannot get from annotations or schema.

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 dense sentences front-loading the core identity, then the radius/ordering/units, then the cost model. No filler; every clause carries information an agent needs.

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?

Covers data source, geographic constraint, proximity behavior, units, and payment model for a no-output-schema read tool. The main missing piece is pagination context and explicit routing versus search_addresses, but the essentials are present.

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 each parameter's meaning is fully documented in the schema. The description reinforces radius units (metres) but adds nothing beyond what the schema already provides. Baseline 3 is correct.

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+resource (addresses near a point) with data source (Kartverket), geographic scope (Norwegian), ordering (nearest first), and return unit (distance in metres). Clearly distinguishable from the sibling search_addresses.

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 implies this is a proximity/radius search by naming Kartverket and the radius range, but never explicitly says when to use this versus search_addresses. No exclusions or alternative selection criteria are given.

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