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

With no annotations, the description carries the behavioral burden and does disclose the key traits: paid call at $0.30 USDC on Base via x402, and the output shape (PROPAGATES/ISOLATED plus per-link strength). Remaining gaps are latency/rate-limit behavior, which are secondary.

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?

Front-loaded with the core question and tight overall, with the pricing note parked at the end where it belongs. The telegraphic arrow notation and fragment phrasing cost some readability.

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?

Covers what it computes, the qualitative caveat, the categorical output, and the payment requirement, enough to call it correctly despite the absence of an output schema. A brief note on how many candidates are supported 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?

Schema coverage is 100% and both parameters are already documented, so baseline 3 applies. The description usefully establishes the anchor-as-news-source / candidates-as-tested relationship, but adds no format or selection guidance for the optional candidates list.

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 analysis: 30-day hourly return correlation between an anchor ticker and related perps, returning PROPAGATES/ISOLATED. The concrete contrast (ETH->LINK strong, NVDA->RENDER weak) makes the operation unambiguous and no sibling covers anything similar.

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 framing 'Does news about coin X move Y?' plus the 'not narrative' qualifier implies when to reach for it (measured correlation rather than sentiment/narrative checks), but it never says when not to use it, nor names an alternative for the unmeasured-narrative case.

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