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

Annotations already cover read-only/idempotent/open-world, and the description adds substantial non-obvious behavior: the agent's own wallet pays, this server never holds a wallet or pays on the user's behalf, and the first call is free to retrieve the payment challenge. This is exactly the kind of payment-flow disclosure annotations cannot express.

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 price and purpose, and the payment steps follow logically. Slightly redundant in restating the $0.03/USDC/x402 payment detail in two places, which costs it a point.

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?

No output schema exists, but the description makes clear the return is the union of filings + company facts for one company, so an agent knows what to expect. With annotations covering safety and the schema covering inputs, the only residual gap is explicit return-shape detail, which is minor given the explicitly named constituent tools.

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 the schema already documents all 8 parameters including the nested payment_header. The description adds the nuance that business arguments must be reused identically across the two calls, but no format or constraint detail beyond the schema. Baseline 3 is appropriate.

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 verb+resource: it bundles edgar_filings + edgar_company_facts for one company in a single paid call, and even quantifies the cost advantage over buying both ($0.04 vs $0.03). An agent can identify the constituents and the combined resource 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?

Gives clear operational context: call with no payment_header first to get the x402 challenge, then re-call with the same business arguments plus the signed header. It implies use-when-you-need-both via the 'cheaper than buying both separately' framing, but never explicitly routes to edgar_filings or edgar_company_facts for single-need cases.

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