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

With only readOnlyHint and openWorldHint declared, the description carries the rest and does so well: explicit cost ($2 USDC via x402), a no-charge guarantee when sources are insufficient, and the async nuance that the core source is checked before the job is queued and charged. It also notes the 7-day PDF link, which is real behavioral detail absent from annotations.

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 deliverable and its sources, then cost/refund/async mechanics. The opening sentence is clause-heavy, but almost every clause adds distinct information (sources, time span, output), so little is wasted.

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, yet the description enumerates what the report contains (headline results vs prior periods, drivers, margins, cash, outlook, management tone change) plus the PDF artifact, cost, and refund/async behavior. An agent has everything needed to decide, price, and invoke it correctly.

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 75% and the description meaningfully extends it, particularly for async — explaining that the core source is pre-checked so the job is only charged when it will likely succeed, and that the result can arrive via webhook_url. The pdf and ticker params get less added meaning, but the async/webhook interaction is genuinely beyond the schema text.

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 ('Earnings analysis of a US public company's latest 10-Q or 10-K') and enumerates exactly which sources are read (MD&A, 3 years of quarterly XBRL, 8-K events, news). This is clearly separable from siblings like report_stock, report_company, or sec_financials 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?

The scope clause ('US public company's latest 10-Q or 10-K') implicitly tells the agent when this tool applies, and the async/refund clauses give operational conditions. However, no sibling is named as the alternative for related-but-different requests (e.g. stock screening, generic company research), so routing still requires inference.

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