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

With no annotations, the description carries the full burden. It openly discloses the free/premium distinction, the best-effort nature of BTC trend with null fallback when the feed is unreachable, and that it is 'not advice.' These details provide meaningful behavioral transparency for a read-only tool, though it omits details like rate limits or authentication specifics.

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?

The description is front-loaded with a compelling question, then efficiently explains the output type, the free/premium distinction, and the reliability caveat. Every sentence adds unique information, and the structure is compact and easy to scan.

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?

Given that there is no output schema, the description partially explains the return value (label vs. driver details) but does not describe the full response structure. It also leaves the two parameters unexplained, creating a significant gap for an agent trying to invoke the tool correctly. The core behavior is covered, but the parameter omission limits completeness.

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 schema has two parameters (payment, session_token) with no descriptions (0% coverage). The description mentions 'Free = the label; premium = every driver,' which hints at payment but never explains how to set the payment parameter or what session_token is for. It fails to compensate adequately for the missing schema descriptions.

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 states the tool's purpose by posing the question 'Is the market risk-on or risk-off right now?' and specifying the output categories (BULLISH/BEARISH/CHOPPY) derived from a breadth + relative-strength composite. It explicitly distinguishes itself from a forecast and other sibling tools that provide different market analytics.

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 gives clear context on when to use the tool—when you need the current market regime—and clearly states what it is not (a forecast). However, it does not explicitly name alternative tools or provide direct when-not-to-use scenarios, so it stops short of a 5.

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