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

Annotations already establish readOnly/idempotent/non-destructive, and the description adds the genuinely useful behavioral facts: free, no wallet, no payment, no arguments. It does not describe what the preview actually contains or whether the sample values are real or synthetic, which is the one remaining behavioral gap.

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 front-loaded sentence that leads with the free-preview nature and packs cost, payment, and argument requirements without waste. Nothing to trim.

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 simple zero-param preview with full annotation coverage and no output schema, the description covers selection and invocation fully. It is only slightly thin on what data the snapshot preview actually demonstrates (Treasury fiscal content), which an agent might want before choosing this over another preview.

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, so there is nothing to disambiguate; the description correctly confirms 'no arguments needed,' matching the empty schema with additionalProperties=false. Baseline 4 for a 0-parameter tool.

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 names the exact resource it mirrors (treasury_fiscal_snapshot) and states the tool's distinct role: a free sample response that shows the shape before payment. That cleanly separates it from the paid sibling and from other *_preview tools in the catalog.

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?

It explicitly says when to use it (to see the response shape before paying 0.005 USDC) and when not to (no wallet, no payment, no arguments needed), implicitly routing real data consumers to treasury_fiscal_snapshot. Nothing is left to inference.

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