io.github.mohammad-abbasi-sh/ecb-mcp

ecb_bond_yields

Retrieve AAA-rated euro-area government bond spot yields for a chosen maturity, such as 10Y, over a specified number of recent days.

Instructions

AAA-rated euro-area government bond spot yields (%). maturity: 1Y, 2Y, 5Y, 10Y (default), 20Y or 30Y. limit: 1..30 days (default 5).

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "ecb_bond_yields"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No
`maturity`	No		10Y

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 13, 2026

TDQS

A3.5/5.0

Behavior3/5

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

No annotations are supplied, so the description carries the full burden. It usefully discloses the unit (percent), the data universe (AAA-rated euro-area sovereigns) and a validity range for limit (1..30) that is absent from the schema. It says nothing about observation frequency, data lag, or error behavior for out-of-range limits.

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

Conciseness5/5

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

Three short lines, front-loaded with the core resource and unit, followed by per-parameter constraints. No filler sentences, and the default values are called out inline where they are needed.

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

Completeness4/5

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

For a two-parameter read tool with an output schema, this is nearly sufficient — return values need not be explained. The remaining gap is the ambiguous meaning of 'limit' and the absence of any stated cadence or recency of the yield series.

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 0% and the schema has no enum, so the description must compensate; it does by enumerating the six allowed maturity values with the default flagged. The limit range of 1..30 is also added, though 'days' is ambiguous — it is unclear whether this means observations or a lookback window.

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

Purpose4/5

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

Names a specific resource and metric: 'AAA-rated euro-area government bond spot yields (%)'. That is clearly distinct from siblings like ecb_inflation, ecb_money_supply and ecb_exchange_rates. The only shortfall is that no verb (e.g. 'Returns') is stated, but the intent is unambiguous.

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

Usage Guidelines2/5

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

There is no when-to-use or when-not guidance and no alternative is referenced. An agent must infer that this is the yields tool rather than ecb_interest_rates purely from the name and phrasing. The maturity list implies the main use case but does not guide selection.

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

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