billingo-mcp

Get currency conversion rate

billingo_get_conversion_rate

Read-onlyIdempotent

Get the exchange rate Billingo applies between two currencies, optionally for a specific date, so invoices use the correct conversion rate.

Instructions

Returns the conversion rate Billingo would apply between two currencies.

Input Schema

Name	Required	Description
`to`	Yes	Target currency.
`date`	No	Rate as of this date. Omit for today's rate. For a backdated or historical document, pass its fulfillment_date here — otherwise you'll get today's rate on a document dated in the past.
`from`	Yes	Source currency.

Output Schema

Name	Required	Description	Default
`date`	No
`to_currency`	No
`from_currency`	No
`conversation_rate`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.3Oct 29, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": {},
+  "properties": {
+    "conversation_rate": {
+      "type": [
+        "number",
+        "string",
+        "null"
+      ]
+    },
+    "date": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "from_currency": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "to_currency": {
+      "type": [
+        "string",
+        "null"
+      ]
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0Sep 2, 2026

TDQS

B3.3/5.0

Behavior3/5

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

Annotations already declare readOnly, idempotent, and openWorld, so safety is covered. The description adds meaningful context by specifying this is the rate Billingo itself would apply rather than a market rate. It stops short of disclosing rounding/precision, direction semantics, or freshness behavior, which are relevant for a rate lookup.

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?

A single compact sentence with the key qualifier ('Billingo would apply') front-loaded. No wasted words.

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

Completeness3/5

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

An output schema exists so return-value explanation isn't required, and the schema fully documents parameters. But for a tool whose main misuse risk is fetching today's rate for a historical document, the description omits that context entirely, leaving the schema's date note to carry it.

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

Parameters3/5

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

Schema description coverage is 100%, with clear enum and a well-annotated date parameter, so the baseline of 3 applies. The description itself contributes nothing to parameter meaning — it never mentions source/target ordering or the date option.

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 verb ('Returns') and resource ('conversion rate') with a scope qualifier ('between two currencies'), and the phrase 'Billingo would apply' distinguishes it from a generic market-rate lookup. No sibling tool offers a comparable function, so no explicit differentiation is needed, but the definition doesn't call out its uniqueness.

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?

The description gives no guidance on when to call this versus other tools, no mention of prerequisites, and no hint that the date parameter supports historical rates — that crucial guidance ('for a backdated document pass its fulfillment_date') lives only in the schema, not the prose.

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