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

Beyond readOnlyHint/openWorldHint, the description discloses freshness ('new rounds appear within days'), a real data-quality caveat ('amounts as DefiLlama lists them and can be missing for undisclosed rounds'), and the cost/payment mechanics ($0.002 USDC per successful call via x402 on Base, Solana or Arc; failed calls not charged). The billing and auth requirement is exactly the context an agent needs before invoking a paid tool.

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 dense sentences: what/where first, filter capability second, data-quality and pricing caveats last. No filler, and the most decision-critical facts (source, cost) are front-loaded.

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 and full parameter documentation, the description needn't explain return values, and it still covers source, freshness, gaps and payment. The only residual gap is result ordering/pagination behavior when limit truncates a large window.

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 description coverage is 100%, so every parameter already carries defaults, ranges and examples; the baseline is 3. The description adds only indirect meaning (that amounts may be missing, relevant to minAmountUsd), without clarifying filter interaction such as chain/category matching semantics.

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 the exact resource (crypto/Web3 venture funding rounds with project, date, round type, amount, valuation, investors, category, chains) and its source (DefiLlama Raises page), so the agent knows precisely what data comes back. It does not explicitly distinguish itself from adjacent siblings such as finance_pitchbook_investors or finance_sec_form_d, which keeps it below 5.

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 lists the filter dimensions available (date window, investor, category, chain, round, minimum amount), which implies how to narrow results, and the schema notes that 'days' is ignored when 'since' is given. However, there is no explicit when-to-use guidance, no statement of when-not to use it, and no named alternative for non-crypto funding data.

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