preview_reportFetch the free machine-readable cross-section for one report: the latest year for every economy, the exact field names and types the paid payload uses, and what the purchase adds. No payment. Use this to verify coverage before paying.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Report id, e.g. "macro-inflation" or "yearbook-2024". |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It states the operation is free, involves no payment, and returns a preview with specific content, which effectively signals a safe, read-only action. It doesn't discuss auth, errors, or rate limits, but for a simple fetch these are not critical gaps.
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?
Two sentences, front-loaded with the action and resource, then a compact list of what the preview contains. No filler or redundancy.
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?
Despite no output schema, the description tells the agent what the response will contain: latest year per economy, field names/types, and what purchase adds. Together with the single documented parameter, this is enough to select and invoke the tool 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?
The schema already documents the single required id with examples and 100% coverage. The description only says 'for one report,' which adds minimal meaning beyond the schema. Baseline 3 is appropriate when the schema carries the parameter documentation.
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?
Description uses a specific verb ('Fetch'), names the resource ('free machine-readable cross-section for one report'), and details exactly what the preview contains. The emphasis on 'No payment' and 'before paying' clearly distinguishes it from buy_report and other catalog tools.
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 final sentence provides an explicit use case: 'Use this to verify coverage before paying.' This implies the correct ordering relative to buy_report and clarifies the tool is not for purchasing. It does not explicitly name sibling alternatives or exclusion conditions, so it stops short of a 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.