Medical Terminologies MCP

RxNorm / NDC Mapping

rxnorm_ndc

Read-onlyIdempotent

Map between RxNorm RxCUI and National Drug Code (NDC) identifiers: look up all NDCs for a drug or find the RxCUI for an NDC code.

Instructions

Map between RxNorm concepts and National Drug Codes (NDC).

Use this tool to:

Get all NDC codes for a drug (by RxCUI)
Find the RxCUI for an NDC code
Cross-reference between coding systems

Provide either an RxCUI to get NDCs, or an NDC to get the RxCUI.

Input Schema

Name	Required	Description	Default
`ndc`	No	NDC code to look up RxCUI (alternative to rxcui)
`rxcui`	No	RxCUI to get NDC codes for

Output Schema

Name	Required	Description
`ndc`	Yes	rxcui_for_ndc: the NDC as submitted; null in ndcs_for_rxcui mode.
`ndcs`	Yes	ndcs_for_rxcui: NDC codes RxNorm lists for the RxCUI (empty when none); always empty in rxcui_for_ndc mode.
`rxcui`	Yes	ndcs_for_rxcui: the RxCUI as submitted. rxcui_for_ndc: the RxCUI the NDC belongs to, or null when RxNorm has none for it.
`provenance`	Yes	Provenance block: source, URL, data vintage, extraction instant, origin diagnostics, citation, license
`query_mode`	Yes	Which lookup ran: ndcs_for_rxcui (rxcui given, list its NDCs) or rxcui_for_ndc (ndc given, find its RxCUI).
`attribution`	Yes	Canonical source URLs of this response (attribution list)

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv2.4.0Oct 29, 2026

addedOutput schema / properties / ndc / description

Added value: +"rxcui_for_ndc: the NDC as submitted; null in ndcs_for_rxcui mode."

addedOutput schema / properties / ndcs / description

Added value: +"ndcs_for_rxcui: NDC codes RxNorm lists for the RxCUI (empty when none); always empty in rxcui_for_ndc mode."

addedOutput schema / properties / query_mode / description

Added value: +"Which lookup ran: ndcs_for_rxcui (rxcui given, list its NDCs) or rxcui_for_ndc (ndc given, find its RxCUI)."

addedOutput schema / properties / rxcui / description

Added value: +"ndcs_for_rxcui: the RxCUI as submitted. rxcui_for_ndc: the RxCUI the NDC belongs to, or null when RxNorm has none for it."

Changed7 schema fields changedv2.3.0Oct 16, 2026

changedOutput schema / properties / provenance / description

Previous value: -"Provenance block (contract v1.1): source, URL, data vintage, extraction instant, origin diagnostics, citation, license"New value: +"Provenance block: source, URL, data vintage, extraction instant, origin diagnostics, citation, license"

addedOutput schema / properties / provenance / properties / derivation_note

Added value: +{
+  "description": "What this server computed; present together with derived",
+  "type": "string"
+}

addedOutput schema / properties / provenance / properties / derived

Added value: +{
+  "description": "Present (true) only when this server computed the value (e.g. a ranking or summary statistics) instead of passing on what the source returned",
+  "type": "boolean"
+}

changedOutput schema / properties / provenance / properties / field_sources / description

Previous value: -"Present only when the response joins parts from different origins or extraction instants (contract v1.2): for each group of fields, its URL, extraction instant and whether it came from cache. Absent in single-origin responses"New value: +"Present only when the response joins parts from different origins or extraction instants: for each group of fields, its URL, extraction instant and whether it came from cache. Absent in single-origin responses"

addedOutput schema / properties / provenance / properties / notices

Added value: +{
+  "description": "Caveats the source publishes about the data, verbatim (license statements are not repeated here; see the info://licenses resource). Absent when there is none",
+  "items": {
+    "type": "string"
+  },
+  "minItems": 1,
+  "type": "array"
+}

changedOutput schema / properties / provenance / properties / retrieval / description

Previous value: -"Origin diagnostics of THIS source in this call (contract v1.1): requests made to the upstream, attempts summed across retries, anomalies worked around (kind + count); unstable=true when any anomaly happened. null when nothing was measured (bundled dataset, or response served entirely from cache)"New value: +"Origin diagnostics of THIS source in this call: requests made to the upstream, attempts summed across retries, anomalies worked around (kind + count); unstable=true when any anomaly happened. null when nothing was measured (bundled dataset, or response served entirely from cache)"

addedOutput schema / properties / provenance / properties / revision

Added value: +{
+  "additionalProperties": false,
+  "description": "Whether the data can still change at the source: current = the version in force, the source may revise it; provisional = preliminary; final = will not change. Absent when unknown",
+  "properties": {
+    "note": {
+      "description": "O específico da fonte: o que revisa, quando, por quê",
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "status": {
+      "description": "current = versão vigente, a fonte pode revisá-la; provisional = preliminar, incompleta ou sujeita a mudança (não compare como se fosse fechada); final = não muda mais, declarado pela fonte",
+      "enum": [
+        "current",
+        "provisional",
+        "final"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "status",
+    "note"
+  ],
+  "type": "object"
+}

Changed1 schema field changedv2.1.1Oct 7, 2026

addedOutput schema / properties / provenance / properties / field_sources

Added value: +{
+  "description": "Present only when the response joins parts from different origins or extraction instants (contract v1.2): for each group of fields, its URL, extraction instant and whether it came from cache. Absent in single-origin responses",
+  "items": {
+    "additionalProperties": false,
+    "description": "Proveniência de um grupo de campos da resposta: de onde veio e quando foi extraído",
+    "properties": {
+      "data_vintage": {
+        "description": "Vintage/competência da sub-fonte",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "dataset_id": {
+        "description": "Identificador do conjunto da sub-fonte",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "fields": {
+        "description": "Campos do payload atribuídos a esta sub-fonte",
+        "items": {
+          "type": "string"
+        },
+        "minItems": 1,
+        "type": "array"
+      },
+      "retrieved_at": {
+        "description": "ISO-8601 da extração desta sub-fonte na origem",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "served_from_cache": {
+        "description": "true se esta sub-fonte veio do cache do servidor (retrieved_at é o da extração original); false se foi buscada nesta chamada; null se o servidor não distingue",
+        "type": [
+          "boolean",
+          "null"
+        ]
+      },
+      "source_url": {
+        "description": "URL canônica da sub-fonte que originou estes campos",
+        "type": "string"
+      }
+    },
+    "required": [
+      "fields",
+      "source_url",
+      "dataset_id",
+      "data_vintage",
+      "retrieved_at"
+    ],
+    "type": "object"
+  },
+  "minItems": 1,
+  "type": "array"
+}

Changed3 schema fields changedv1.16.0Oct 1, 2026

addedInput schema / properties / rxcui / anyOf

Added value: +[
+  {
+    "pattern": "^\\d+$",
+    "type": "string"
+  },
+  {
+    "maximum": 9007199254740991,
+    "minimum": 0,
+    "type": "integer"
+  }
+]

removedInput schema / properties / rxcui / pattern
```
Removed value: -"^\\d+$"
```
removedInput schema / properties / rxcui / type
```
Removed value: -"string"
```

Changed3 schema fields changedv1.15.0Sep 27, 2026

changedOutput schema / properties / provenance / description

Previous value: -"Provenance block (contract v1.0): source, URL, data vintage, extraction instant, citation, license"New value: +"Provenance block (contract v1.1): source, URL, data vintage, extraction instant, origin diagnostics, citation, license"

addedOutput schema / properties / provenance / properties / retrieval

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "anomalies": {
+          "description": "Anomalias superadas até o sucesso, somadas por classe, em ordem fixa; [] se nenhuma",
+          "items": {
+            "additionalProperties": false,
+            "properties": {
+              "count": {
+                "description": "Ocorrências desta classe na chamada",
+                "maximum": 9007199254740991,
+                "minimum": 1,
+                "type": "integer"
+              },
+              "kind": {
+                "description": "Classe da anomalia (vocabulário fechado do contrato)",
+                "enum": [
+                  "timeout",
+                  "network",
+                  "http_4xx",
+                  "http_5xx",
+                  "rate_limited",
+                  "malformed_body"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "kind",
+              "count"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "attempts": {
+          "description": "Tentativas somadas, incluindo as repetidas (>= requests)",
+          "maximum": 9007199254740991,
+          "minimum": 1,
+          "type": "integer"
+        },
+        "requests": {
+          "description": "Idas distintas à origem que compõem esta resposta (fatias, páginas)",
+          "maximum": 9007199254740991,
+          "minimum": 1,
+          "type": "integer"
+        },
+        "unstable": {
+          "description": "true se houve repetição (attempts > requests) ou alguma anomalia",
+          "type": "boolean"
+        }
+      },
+      "required": [
+        "requests",
+        "attempts",
+        "anomalies",
+        "unstable"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Origin diagnostics of THIS source in this call (contract v1.1): requests made to the upstream, attempts summed across retries, anomalies worked around (kind + count); unstable=true when any anomaly happened. null when nothing was measured (bundled dataset, or response served entirely from cache)"
+}

changedOutput schema / properties / provenance / required

Previous value: -[
-  "source",
-  "source_url",
-  "data_vintage",
-  "retrieved_at",
-  "citation",
-  "license"
-]New value: +[
+  "source",
+  "source_url",
+  "data_vintage",
+  "retrieved_at",
+  "retrieval",
+  "citation",
+  "license"
+]

Changed1 schema field changedv1.11.0Sep 15, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed8 schema fields changedv1.9.1Sep 1, 2026
- removedOutput schema / properties / ndc / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / ndc / type
```
Added value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / provenance / properties / data_vintage / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / provenance / properties / data_vintage / type
```
Added value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / provenance / properties / license / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / provenance / properties / license / type
```
Added value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / rxcui / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / rxcui / type
```
Added value: +[
+  "string",
+  "null"
+]
```

Changed3 schema fields changedv1.8.0Aug 10, 2026

addedOutput schema / properties / attribution

Added value: +{
+  "description": "Canonical source URLs of this response (attribution list)",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

addedOutput schema / properties / provenance

Added value: +{
+  "additionalProperties": false,
+  "description": "Provenance block (contract v1.0): source, URL, data vintage, extraction instant, citation, license",
+  "properties": {
+    "citation": {
+      "description": "Ready-to-use citation/attribution string",
+      "type": "string"
+    },
+    "data_vintage": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "description": "Version/release of the data as exposed by the source; null when not exposed"
+    },
+    "license": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "description": "License / legal regime of the data"
+    },
+    "retrieved_at": {
+      "description": "Real instant of the upstream extraction (ISO-8601, UTC). Responses served from cache keep the ORIGINAL fetch instant.",
+      "type": "string"
+    },
+    "source": {
+      "description": "Official upstream source of this data",
+      "type": "string"
+    },
+    "source_url": {
+      "description": "Canonical URL of the source (API base or dataset release)",
+      "type": "string"
+    }
+  },
+  "required": [
+    "source",
+    "source_url",
+    "data_vintage",
+    "retrieved_at",
+    "citation",
+    "license"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "query_mode",
-  "rxcui",
-  "ndc",
-  "ndcs"
-]New value: +[
+  "query_mode",
+  "rxcui",
+  "ndc",
+  "ndcs",
+  "provenance",
+  "attribution"
+]

Changed5 schema fields changedv1.5.7Jun 21, 2026

removedInput schema / additionalProperties
```
Removed value: -false
```

addedOutput schema / properties / ndc / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

removedOutput schema / properties / ndc / type

Removed value: -[
-  "string",
-  "null"
-]

addedOutput schema / properties / rxcui / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

removedOutput schema / properties / rxcui / type
```
Removed value: -[
-  "string",
-  "null"
-]
```

First observedv1.2.1May 11, 2026

TDQS

A3.6/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that the tool is bidirectional and takes exactly one identifier, but says nothing about cardinality of results (one NDC vs many), unmatched-code behavior, or partial-match handling — the openWorldHint suggests external lookups, yet no failure mode is described.

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 one-line purpose followed by scannable bullets and a closing input rule; nothing is buried. The 'Cross-reference between coding systems' bullet is somewhat redundant with the opening sentence, a minor bit of waste.

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?

With an output schema present and rich annotations, the description need not explain return values, and it correctly covers the input contract. What a caller would still want — what happens when neither parameter is supplied (both are optional) or when a code has no mapping — is left implicit.

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% and each property already documents its direction ('NDC code to look up RxCUI', 'RxCUI to get NDC codes for'). The description restates the either/or contract, which is useful for signaling mutual exclusivity but adds little beyond the schema wording — baseline 3.

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?

The first sentence names a specific operation and both resource types (RxNorm concepts and NDC codes), and the bullets spell out the two directions of the mapping. It is clearly distinguishable from rxnorm_search or rxnorm_concept by virtue of being a cross-terminology mapping, though it never names a sibling explicitly.

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?

The 'Use this tool to' bullets give concrete tasks and the closing line states the input contract ('Provide either an RxCUI ... or an NDC ...'). It lacks any when-not guidance or named alternative (e.g., use rxnorm_search to find an RxCUI first), which keeps it below a 5.

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