euroref — European government reference data

compare_series

Read-onlyIdempotent

PAID ($0.02). One series (e.g. vat, policy-rate, minimum-wage, corporate-tax) across up to 10 countries of this brand in one call; each row carries its own source, dates and labels, and countries without the series are listed under missing. Malformed requests are refused free. Pass api_key if you have one; otherwise the response explains how to pay via x402. After a 200, bind get_changes (free poll) or register_alert (HMAC push; Register: $0 · Delivery after trial: $0.05) on this series so a later gazette does not silently retire the value.

Input Schema

TableJSON Schema

Name	Required	Description
`series`	Yes	Series id from list_series, e.g. vat
`api_key`	No	API key
`countries`	Yes	ISO 3166-1 alpha-2 codes on this brand, at most 10

Output Schema

TableJSON Schema

Name	Required	Description
`rows`	No
`as_of`	No
`count`	No
`error`	No	Present on a free refusal or error; no charge
`series`	No
`missing`	No
`no_charge`	No
`price_usd`	No
`disclaimer`	No
`how_to_pay`	No
`bind_series`	No
`explanation`	No
`x_next_bind`	No
`http_endpoint`	No
`payment_required`	No	true when the call needs payment; how_to_pay explains x402 or card

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedOct 17, 2026
- removedOutput schema / properties / rows / items / properties / label_basis / properties / source_type / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / rows / items / properties / label_basis / properties / source_type / type
```
Added value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / rows / items / properties / label_basis / properties / verification_age_days / anyOf
```
Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / rows / items / properties / label_basis / properties / verification_age_days / type
```
Added value: +[
+  "number",
+  "null"
+]
```
AddedOct 17, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Goes well beyond the annotations by disclosing cost ($0.02), that malformed requests are refused free, that missing countries are surfaced under a 'missing' key, that each row carries its own source/dates/labels, and the api_key vs x402 payment path. Annotations cover safety/idempotency, but this adds concrete pricing, error and auth behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the paid cost and the core one-series-many-countries scope, and each clause carries operational detail. It is a dense run-on paragraph and includes sibling pricing ('Register: $0 · Delivery after trial: $0.05') that is arguably outside this tool's remit.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a paid, open-world read tool with an output schema, the description covers cost, payment/auth paths, error handling, the missing-countries behavior, and the recommended follow-up binding. Nothing an agent needs to invoke it correctly is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3, and the description adds value by giving concrete series examples (vat, policy-rate, minimum-wage, corporate-tax) and restating the 10-country cap, plus explaining the api_key alternative path. It stops short of documenting any format beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (compare) and resource (one series across countries) with scope bounded to 'up to 10 countries of this brand in one call'. It is clearly distinguishable from siblings like get_series (single fetch) and get_series_history (time series) because it frames the multi-country, single-call dimension.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear context for when it applies (one series, many countries) and names the correct follow-up tools (get_changes or register_alert) to use after a 200. It does not, however, explicitly contrast itself with get_series/get_snapshot, so the 'when not to use' side 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.

All euroref — European government reference data tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?