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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds useful behavioral context by stating no API key is required and that the data is machine-readable, which helps an agent decide whether it can call the tool without auth.

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 short sentences, each earning its place: core purpose, data equivalence to /pricing.json, and auth requirement. It is front-loaded and contains no filler.

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 zero-parameter, read-only pricing endpoint with no output schema, the description provides everything needed: what data is included, where it matches from, and that no key is needed. Nothing critical is missing.

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 tool has zero parameters and schema coverage is 100%, so there is nothing for the description to explain about inputs. The baseline for a no-parameter tool is 4, and the description adds no unnecessary parameter-related content.

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 identifies the resource (agentcheck pricing) and its contents (tiers, monthly USD price, limits, interval, features, add-ons), and it is distinct from all sibling tools. It uses a noun phrase rather than an explicit verb like 'retrieves', but the meaning is 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 provides clear context: this is the machine-readable pricing data, equivalent to /pricing.json, and no API key is needed. It does not explicitly discuss when not to use it or compare it to sibling tools, but for a zero-parameter read-only pricing lookup this is sufficient guidance.

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