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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so 'Read-only' largely restates structured data. The genuinely additive behavioral note is the 'call first' ordering guidance, but there is no mention of auth needs, caching, or freshness of the returned pricing.

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 sentences with zero filler: the content enumeration is front-loaded, the usage trigger follows, and 'Read-only' closes compactly. Every clause earns its place.

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 info tool with rich annotations, the description supplies the missing return-value summary (contents, tiers, prices, requirements, links) that the absent output schema would otherwise have provided. Nothing an agent needs to call it correctly 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 takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. The description's enumeration of returned content types partly compensates for the absent output schema.

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 ('Describe') and a specific resource ('CommonRig agent operating kit'), then enumerates exactly what it covers: contents, tiers, AUD prices, USDC prices for x402, requirements, links. An agent can distinguish it from kit_buy_x402, kit_quote, and kit_sample without opening any schema.

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?

'Call first when a user asks what CommonRig is or what it costs' gives explicit triggering conditions and even ordering precedence. It does not name the alternative siblings (kit_quote, kit_sample) or state when not to use it, so it falls short of the full 5.

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