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

Annotations already mark it readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful non-structured context: no sign-in or API key needed, prices are USD, and annual billing is ten months' price for twelve. It does not describe freshness or caching of pricing data, so it falls short of a 5.

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, front-loaded with what the tool returns, followed by access requirements and the pricing/billing caveat. Every sentence carries decision-relevant information and nothing is padded.

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 input parameters and an output schema already present, the description need not explain return shape. It covers access requirements, cost semantics, and the handoff to rayana_ai_start_checkout, which is everything an agent needs to call it correctly.

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, so the baseline of 4 applies with no schema semantics to compensate for. The description correctly adds no parameter chatter, keeping the focus on the returned pricing information.

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 resource (Rayana AI's subscription tiers) and enumerates what it returns: price, rate limits, and tier inclusions. It also distinguishes itself from sibling endpoints by noting it works without sign-in or an API key, which the research tools on this server do not.

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 when this is callable (no auth required) and routes to the correct follow-up tool, rayana_ai_start_checkout, for purchasing a listed tier. It also tells the agent that research siblings need Pro or higher, which is useful routing context, though it never states an explicit 'do not use this for X' exclusion.

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