kegg-mcp-server

find_related_entries

Read-onlyIdempotent

Find related KEGG entries by taking a source entry ID and target database, returning up to 100 linked records for cross-database mapping and analysis.

Instructions

Find related entries in another KEGG database for a given entry.

Args: entry_id: Source KEGG entry ID (e.g. 'hsa:1956', 'C00002', 'K00844'). target_db: Target database (e.g. 'pathway', 'disease', 'drug', 'ko', 'compound', 'reaction', 'module', 'genes'). max_results: Maximum number of pairs to return (capped at 100).

Input Schema

Name	Required	Description	Default
`entry_id`	Yes
`target_db`	Yes
`max_results`	No

Output Schema

Name	Required	Description	Default
`count`	Yes
`pairs`	Yes
`source`	Yes
`target_db`	Yes
`truncated`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed10 schema fields changedv0.5.0Oct 23, 2026

addedInput schema / properties / max_results

Added value: +{
+  "default": 100,
+  "title": "Max Results",
+  "type": "integer"
+}

removedOutput schema / $defs

Removed value: -{
-  "ErrorResult": {
-    "description": "Structured error returned by a tool when the KEGG API fails.\n\nA tool returns this instead of raising so the model can reason about\nthe failure and decide whether to retry, change inputs, or give up.\nA point lookup that receives a 404 uses code ``not_found``; an empty search\nremains a successful result with no items.",
-    "properties": {
-      "code": {
-        "default": "kegg_api_error",
-        "title": "Code",
-        "type": "string"
-      },
-      "error": {
-        "title": "Error",
-        "type": "string"
-      },
-      "hint": {
-        "anyOf": [
-          {
-            "type": "string"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "default": null,
-        "title": "Hint"
-      },
-      "path": {
-        "anyOf": [
-          {
-            "type": "string"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "default": null,
-        "title": "Path"
-      },
-      "retryable": {
-        "default": false,
-        "title": "Retryable",
-        "type": "boolean"
-      },
-      "status": {
-        "anyOf": [
-          {
-            "type": "integer"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "default": null,
-        "title": "Status"
-      }
-    },
-    "required": [
-      "error"
-    ],
-    "title": "ErrorResult",
-    "type": "object"
-  },
-  "LinkResult": {
-    "properties": {
-      "count": {
-        "title": "Count",
-        "type": "integer"
-      },
-      "pairs": {
-        "items": {
-          "maxItems": 2,
-          "minItems": 2,
-          "prefixItems": [
-            {
-              "type": "string"
-            },
-            {
-              "type": "string"
-            }
-          ],
-          "type": "array"
-        },
-        "title": "Pairs",
-        "type": "array"
-      },
-      "source": {
-        "title": "Source",
-        "type": "string"
-      },
-      "target_db": {
-        "title": "Target Db",
-        "type": "string"
-      }
-    },
-    "required": [
-      "source",
-      "target_db",
-      "pairs",
-      "count"
-    ],
-    "title": "LinkResult",
-    "type": "object"
-  }
-}

addedOutput schema / properties / count

Added value: +{
+  "title": "Count",
+  "type": "integer"
+}

addedOutput schema / properties / pairs

Added value: +{
+  "items": {
+    "maxItems": 2,
+    "minItems": 2,
+    "prefixItems": [
+      {
+        "type": "string"
+      },
+      {
+        "type": "string"
+      }
+    ],
+    "type": "array"
+  },
+  "title": "Pairs",
+  "type": "array"
+}

removedOutput schema / properties / result

Removed value: -{
-  "anyOf": [
-    {
-      "$ref": "#/$defs/LinkResult"
-    },
-    {
-      "$ref": "#/$defs/ErrorResult"
-    }
-  ],
-  "title": "Result"
-}

addedOutput schema / properties / source

Added value: +{
+  "title": "Source",
+  "type": "string"
+}

addedOutput schema / properties / target_db

Added value: +{
+  "title": "Target Db",
+  "type": "string"
+}

addedOutput schema / properties / truncated

Added value: +{
+  "default": false,
+  "title": "Truncated",
+  "type": "boolean"
+}

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "source",
+  "target_db",
+  "pairs",
+  "count"
+]

changedOutput schema / title

Previous value: -"find_related_entriesOutput"New value: +"LinkResult"

First observedv0.1.0Jul 29, 2026

TDQS

A3.6/5.0

Behavior3/5

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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context: results are returned as pairs and are capped at 100. It does not say what happens when target_db is unsupported or when an entry has no links.

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?

The core purpose is stated in one front-loaded sentence, followed by a compact Args block. The text is short and each line adds information; the only weak point is that it reads as a docstring rather than prose.

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?

The tool takes three parameters, has complete annotations and an output schema, and the description covers all parameter formats. It is adequate for correct invocation. The one gap is guidance on which source-to-target database pairings are valid.

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 description coverage is 0%, so the description must carry the load, and it does. It documents the ID format for entry_id with three concrete examples, enumerates likely target_db values, and states the max_results cap of 100.

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 description gives a specific verb and resource: find related entries in another KEGG database for a given entry. That clearly distinguishes it from siblings such as get_gene_info or search_compounds, which retrieve information about a single entity rather than link one entry to another. It does not explicitly contrast with the closest sibling, convert_identifiers, which also maps one identifier to another.

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

Usage Guidelines3/5

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

The example IDs ('hsa:1956', 'C00002', 'K00844') and example target databases imply when the tool can be used, but there is no explicit statement of when to choose this over convert_identifiers or a get_*_info call. Nothing tells the agent which source or target database combinations are valid.

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