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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the paid cost, payment protocol, exact failure mode when unpaid, and the retry mechanism using x402 payment metadata or the PAYMENT-SIGNATURE header. This is unusually rich behavioral context for an agent 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?

The description is front-loaded with purpose and then payment mechanics, with little wasted text. The technical payment details are dense but necessary for correct invocation.

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?

For a paid read-only tool with no output schema, the description covers the critical payment and error behavior thoroughly. It is slightly incomplete because it does not describe the return shape of the event digest or explicitly contrast with the sibling sample tool.

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 80%, so most parameters are already documented in the schema. The description clarifies that ticker or CIK identifies the target, but adds little semantic detail for forms, limit, or since beyond what the schema already provides.

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 verb and resource: an event digest of recent SEC EDGAR filings for a ticker or CIK. It is clear what the tool returns conceptually, but it does not explicitly differentiate itself from the sibling filings_digest_sample tool.

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 description gives clear usage context by identifying the tool as paid and explaining the x402 payment flow, including retry behavior after a payment challenge. It does not, however, explain when to use this tool instead of the sibling sample tool.

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