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

Goes well beyond the readOnly/openWorld annotations by disclosing the paid model ($0.002 USDC per successful call via x402 on Base, Solana or Arc) and confirming failed calls are not charged — critical for an agent deciding to call a paid endpoint. It also discloses a real data limitation (no realized cap in free tier) and interpretation caveats, none of which appear in structured fields.

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?

Four dense sentences, front-loaded with what is returned, followed by interpretation caveat, data limitation, and price. Every sentence carries distinct, decision-relevant information with no repetition of the title.

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?

Output schema exists and the description still orients the agent by naming the returned fields (latest value, window mean, standard deviation, z-score). Combined with the pricing and free-tier caveats, nothing needed to call this 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?

Schema coverage is 100%, so both parameters are already documented with defaults. The description reinforces that the window is a statistical window (mean/stddev/z-score over 'days') and that asset must be BTC or ETH, but adds no format or syntax detail beyond the schema — the baseline 3 applies.

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 metric and resource — 'Daily MVRV ratio (market cap / realized cap) for BTC or ETH' — and names the data source (CoinMetrics community tier). An agent can distinguish it from siblings like agent_intel_sopr_profit_taking_ratio or agent_intel_token_verdict_engine 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?

Provides clear usage context: BTC/ETH only, daily window, output labels are statistics 'not buy or sell calls', and the free tier cannot return realized cap. It does not explicitly name a sibling alternative or state when-not to use it, 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.