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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds genuinely new behavioral context: cost ($0.03/call via x402 on Base), the prepaid x-credit-token header, 1 free call/day, and no API key needed. It also frames the output's epistemic status ('a gauge, not a signal. Not financial advice'), which is useful for downstream reasoning.

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 core concept is front-loaded, but the description is ~150 words for a zero-parameter tool and carries marketing flourish ('trading-grade read', 'the edge is the combination') that repeats the point. The pricing/header mechanics at the tail are useful but could be tightened.

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 an output schema present, the description needn't enumerate return values, yet it helpfully names the stance values anyway. Combined with the pricing/auth transparency, it is largely complete for a no-input, read-only gauge; only explicit sibling routing is absent.

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 is 4 per the rubric. There is no parameter syntax or format to document, and the description correctly spends no space on inputs.

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 a specific composite resource (mood + attention + leverage) and the concrete output (a stance from frothy / capitulation_setup / risk_on / risk_off / neutral). It implicitly differentiates from the fear_greed sibling by positioning the combined read as the point ('where the single Fear & Greed number isn't enough'). An agent can distinguish this from fear_greed, crypto_trending, or perp_funding 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?

It states the usage context clearly ('one read where the single Fear & Greed number isn't enough') and gives interpretive guidance (greed + crowded longs = froth risk, fear + crowded shorts = capitulation setup). However it never names a sibling to use instead when only one angle is needed, so the when-not guidance is implied rather than explicit.

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