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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so safety and determinism are covered. The description adds one useful nuance — these are the rules "as the network actually computes them," i.e. de facto behavior rather than advertised policy — but says nothing further about freshness, caching, or authority of the content.

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?

A single front-loaded sentence that defines the resource first and then lists the topics covered. Every clause earns its place, and there is no filler or redundancy.

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 no parameters and an output schema present, the description need not explain return values and correctly focuses on scope. It is complete enough for correct invocation, though stating that the returned rules are authoritative/current would close the last gap.

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 takes no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. Schema coverage is 100% with additionalProperties=false, so the empty input contract is fully unambiguous.

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 names the resource (the exchange's rules) and enumerates the specific contents returned: view earnings, view definition, commission, welcome credits, and widget installation. The verb is implicit ("returns/shows") and the tool name alone (how_it_works) would be opaque, but the enumerated scope lets an agent distinguish it from check_site, list_members, and network_stats.

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?

Usage is implied — an agent reads this when it needs the exchange's rules — but there is no explicit when-to-use or when-not statement, and no routing to or away from the sibling tools. Adequate but leaves selection to inference.

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