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

Annotations already declare read-only and open-world access, so the safety profile is covered. The description adds genuinely useful behavioral context beyond them: it is a paid call ($0.002 USDC via x402 across Base/Solana/Arc) and failed calls are not charged — critical for an agent deciding whether to invoke.

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 behavior is front-loaded in the first sentence, and the pricing sentence is dense but each clause carries load-bearing information (cost, payment rails, failure policy). Nothing is redundant with the title or schema.

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?

An output schema exists, so return-value structure need not be explained. The description covers data source (US government), scope (latest 8-Ks), item-code interpretation, document links, and pricing — everything an agent needs to call it correctly, with only sibling routing left implicit.

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 both parameters (company, limit) are already documented. The description restates that company accepts a ticker or CIK but adds no format, range, or default detail beyond the schema, so the baseline 3 is correct.

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 states a specific resource and scope: the latest 8-K current reports for a US company, with item codes explained. The 8-K specificity implicitly separates it from broader siblings like sec_filings or sec_search, but it never names an alternative explicitly, so it stops short of a 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?

Usage is implied by the scope — fetch recent material-event filings for one company — but there is no explicit when-to-use guidance and no mention of when to prefer sec_filings, sec_search, or sec_insiders instead. The agent must infer the routing.

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