Medical Terminologies MCP

Terminology Version Diff

terminology_diff

Read-onlyIdempotent

Report available diff data between medical terminology versions, including ICD-10 vs ICD-11 mapping summaries; directs to publisher changelogs for other terminologies.

Instructions

Report what diff data is available between two versions of a terminology.

For most terminologies this is guidance only — the server doesn't ship historical snapshots, so the tool points at the publisher's official changelog and explains the cadence. bundled_versions lists the version(s) this server actually has on hand.

For ICD-10 vs ICD-11 specifically, the tool surfaces a real cross-revision summary from the bundled WHO transition tables (the ICD-10 → ICD-11 case is a structural diff between two WHO revisions). Use terminology: "icd10" with no to_version to get the cross-revision summary: total mapped ICD-10 categories, how many are 1:1 vs split into multiple ICD-11 codes, and the average number of alternatives when split.

Inputs:

terminology (required): which terminology to report on.
from_version (optional): the version you have data from. If omitted, the tool reports against the currently-bundled version.
to_version (optional): the version you want to compare to. If omitted, the tool reports against the publisher's latest known release.

This tool is intentionally a metadata + guidance layer, not a diff engine — for terminologies that change frequently (LOINC, RxNorm, MeSH), the publisher's official changelog is the authoritative source.

Input Schema

TableJSON Schema

Name	Required	Description
`to_version`	No	Version you want to compare to. Optional.
`terminology`	Yes	Which terminology to report on.
`from_version`	No	Version you have data from. Optional; behavior depends on terminology.

Output Schema

TableJSON Schema

Name	Required	Description
`message`	Yes
`provenance`	Yes	Provenance block (contract v1.1): source, URL, data vintage, extraction instant, origin diagnostics, citation, license
`to_version`	Yes
`attribution`	Yes	Canonical source URLs of this response (attribution list)
`terminology`	Yes
`from_version`	Yes
`changelog_url`	Yes
`diff_available`	Yes	True when this server has the data to compute a real diff for the requested terminology. False = guidance-only response.
`bundled_versions`	Yes
`cross_revision_summary`	Yes	Populated only for terminology="icd10" today — the bundled WHO ICD-10 → ICD-11 transition tables let us surface a real structural diff between the two WHO revisions.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv2.0.0Oct 4, 2026

changedInput schema / properties / terminology / enum

Previous value: -[
-  "icd11",
-  "icd10",
-  "snomed",
-  "loinc",
-  "rxnorm",
-  "mesh",
-  "atc",
-  "cid10"
-]New value: +[
+  "icd11",
+  "icd10",
+  "loinc",
+  "rxnorm",
+  "mesh",
+  "atc",
+  "cid10"
+]

changedOutput schema / properties / terminology / enum

Previous value: -[
-  "icd11",
-  "icd10",
-  "snomed",
-  "loinc",
-  "rxnorm",
-  "mesh",
-  "atc",
-  "cid10"
-]New value: +[
+  "icd11",
+  "icd10",
+  "loinc",
+  "rxnorm",
+  "mesh",
+  "atc",
+  "cid10"
+]

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
```
Changed10 schema fields changedv1.9.1Sep 1, 2026
- removedOutput schema / properties / changelog_url / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / changelog_url / type
```
Added value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / from_version / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / from_version / 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 / to_version / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / to_version / 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: -[
-  "terminology",
-  "from_version",
-  "to_version",
-  "diff_available",
-  "message",
-  "changelog_url",
-  "bundled_versions",
-  "cross_revision_summary"
-]New value: +[
+  "terminology",
+  "from_version",
+  "to_version",
+  "diff_available",
+  "message",
+  "changelog_url",
+  "bundled_versions",
+  "cross_revision_summary",
+  "provenance",
+  "attribution"
+]

Changed8 schema fields changedv1.5.7Jun 21, 2026

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

addedOutput schema / properties / changelog_url / anyOf

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

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

changedOutput schema / properties / cross_revision_summary / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "avg_alternatives_when_split": {
-        "type": "number"
-      },
-      "icd10_categories_total": {
-        "type": "integer"
-      },
-      "one_to_many_splits": {
-        "type": "integer"
-      },
-      "one_to_one_mappings": {
-        "type": "integer"
-      }
-    },
-    "required": [
-      "icd10_categories_total",
-      "one_to_one_mappings",
-      "one_to_many_splits",
-      "avg_alternatives_when_split"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "avg_alternatives_when_split": {
+        "type": "number"
+      },
+      "icd10_categories_total": {
+        "maximum": 9007199254740991,
+        "minimum": -9007199254740991,
+        "type": "integer"
+      },
+      "one_to_many_splits": {
+        "maximum": 9007199254740991,
+        "minimum": -9007199254740991,
+        "type": "integer"
+      },
+      "one_to_one_mappings": {
+        "maximum": 9007199254740991,
+        "minimum": -9007199254740991,
+        "type": "integer"
+      }
+    },
+    "required": [
+      "icd10_categories_total",
+      "one_to_one_mappings",
+      "one_to_many_splits",
+      "avg_alternatives_when_split"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

addedOutput schema / properties / from_version / anyOf

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

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

addedOutput schema / properties / to_version / anyOf

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

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

Addedv1.4.0May 12, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds substantial non-obvious context beyond them: the server lacks historical snapshots, `bundled_versions` reflects what is actually on hand, and frequent-change terminologies defer to the publisher's changelog. This is exactly the behavioral disclosure annotations cannot provide.

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 first sentence and clear Inputs section, sized appropriately for a genuinely nuanced tool. Slightly redundant, repeating 'guidance only' and the publisher's-changelog point, which costs it the top score.

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?

Given an output schema exists, return values need not be explained, and the description covers the branching behavior (guidance vs real ICD-10/ICD-11 summary), the bundled-version concept, and the authority hierarchy. Nothing needed to invoke it correctly is missing.

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 the baseline is 3, but the description adds real semantics the schema lacks: omitting `from_version` reports against the bundled version, omitting `to_version` reports against the publisher's latest known release, and the icd10+no-to_version combination triggers the cross-revision summary. It does not, however, explain the enum members themselves.

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 (report) and resource (diff data between versions of a terminology) and immediately carves out what it is not: 'a metadata + guidance layer, not a diff engine.' This distinguishes it from siblings like map_icd10_to_icd11 (real mapping) and terminology_versions (version listing).

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

Usage Guidelines5/5

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

Explicit when-to-use guidance: for most terminologies it is guidance only and the publisher's changelog is authoritative, while for ICD-10 vs ICD-11 it surfaces a real summary. It even names the exact invocation (`terminology: "icd10"` with no `to_version`), leaving nothing to inference.

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