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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description's job is to add context. It does so by disclosing the pricing model (free vs 0.02 USDC), the absence of any wallet/payment requirement, and that no arguments are needed — none of which is in the 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?

A single tight sentence, front-loaded with the '[FREE]' marker and the preview purpose. Every clause earns its place.

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 no output schema, the description correctly tells the agent this returns a sample response so the shape can be inspected before paying. That covers the essential need for a zero-param preview tool, though it could note the sample is illustrative rather than live data.

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?

The tool takes zero parameters, which is the baseline-4 case. The description confirms 'no arguments needed', matching the empty schema, though there is nothing further to disambiguate.

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 exactly what the tool is: a free sample response for edgar_filings, so the agent can inspect the response shape without paying. The resource and the distinguishing trait versus sibling edgar_filings are both explicit.

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?

Clearly frames when to use it — before spending 0.02 USDC on the paid edgar_filings call — and notes no arguments are required. It does not explicitly state that this is not a substitute for real data, but the 'preview/sample' framing implies it.

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