diff --git a/packages/api/src/router/computation-graph-detail-support.ts b/packages/api/src/router/computation-graph-detail-support.ts
new file mode 100644
index 0000000..e668299
--- /dev/null
+++ b/packages/api/src/router/computation-graph-detail-support.ts
@@ -0,0 +1,111 @@
+export type GraphNodeLike = {
+  id: string;
+  domain: string;
+};
+
+export type GraphLinkLike = {
+  source: string;
+  target: string;
+};
+
+export type ResourceGraphSnapshot = {
+  nodes: GraphNodeLike[];
+  links: GraphLinkLike[];
+  meta: {
+    resourceEid: string;
+    resourceName: string;
+    [key: string]: unknown;
+  };
+};
+
+export type ProjectGraphSnapshot = {
+  nodes: GraphNodeLike[];
+  links: GraphLinkLike[];
+  meta: {
+    projectCode: string;
+    projectName: string;
+    [key: string]: unknown;
+  };
+};
+
+function filterGraphData<
+  TNode extends GraphNodeLike,
+  TLink extends GraphLinkLike,
+>(input: {
+  nodes: TNode[];
+  links: TLink[];
+  domain?: string;
+  includeLinks?: boolean;
+}) {
+  const requestedDomain = input.domain?.trim().toUpperCase();
+  const nodes = requestedDomain
+    ? input.nodes.filter((node) => node.domain === requestedDomain)
+    : input.nodes;
+  const selectedNodeIds = new Set(nodes.map((node) => node.id));
+  const links = input.includeLinks
+    ? input.links.filter((link) => selectedNodeIds.has(link.source) && selectedNodeIds.has(link.target))
+    : [];
+
+  return {
+    requestedDomain: requestedDomain ?? null,
+    includedLinks: input.includeLinks ?? false,
+    selectedNodeCount: nodes.length,
+    selectedLinkCount: links.length,
+    nodes,
+    ...(input.includeLinks ? { links } : {}),
+  };
+}
+
+function getAvailableDomains<TNode extends { domain: string }>(nodes: TNode[]) {
+  return [...new Set(nodes.map((node) => node.domain))];
+}
+
+export function formatResourceGraphDetail(input: {
+  resourceId: string;
+  graph: ResourceGraphSnapshot;
+  domain?: string;
+  includeLinks?: boolean;
+}) {
+  return {
+    resource: {
+      id: input.resourceId,
+      eid: input.graph.meta.resourceEid,
+      displayName: input.graph.meta.resourceName,
+    },
+    availableDomains: getAvailableDomains(input.graph.nodes),
+    totalNodeCount: input.graph.nodes.length,
+    totalLinkCount: input.graph.links.length,
+    ...filterGraphData({
+      nodes: input.graph.nodes,
+      links: input.graph.links,
+      ...(input.domain ? { domain: input.domain } : {}),
+      ...(input.includeLinks !== undefined ? { includeLinks: input.includeLinks } : {}),
+    }),
+    meta: input.graph.meta,
+  };
+}
+
+export function formatProjectGraphDetail(input: {
+  projectId: string;
+  graph: ProjectGraphSnapshot;
+  domain?: string;
+  includeLinks?: boolean;
+}) {
+  return {
+    project: {
+      id: input.projectId,
+      shortCode: input.graph.meta.projectCode,
+      name: input.graph.meta.projectName,
+    },
+    availableDomains: getAvailableDomains(input.graph.nodes),
+    totalNodeCount: input.graph.nodes.length,
+    totalLinkCount: input.graph.links.length,
+    ...filterGraphData({
+      nodes: input.graph.nodes,
+      links: input.graph.links,
+      ...(input.domain ? { domain: input.domain } : {}),
+      ...(input.includeLinks !== undefined ? { includeLinks: input.includeLinks } : {}),
+    }),
+    meta: input.graph.meta,
+  };
+}
diff --git a/packages/api/src/router/computation-graph-detail.ts b/packages/api/src/router/computation-graph-detail.ts
index 937bf0a..48a6642 100644
--- a/packages/api/src/router/computation-graph-detail.ts
+++ b/packages/api/src/router/computation-graph-detail.ts
@@ -1,118 +1,12 @@
 import { z } from "zod";
+import {
+  formatProjectGraphDetail,
+  formatResourceGraphDetail,
+  type ProjectGraphSnapshot,
+  type ResourceGraphSnapshot,
+} from "./computation-graph-detail-support.js";
 import { controllerProcedure } from "../trpc.js";
 
-type GraphNodeLike = {
-  id: string;
-  domain: string;
-};
-
-type GraphLinkLike = {
-  source: string;
-  target: string;
-};
-
-type ResourceGraphSnapshot = {
-  nodes: GraphNodeLike[];
-  links: GraphLinkLike[];
-  meta: {
-    resourceEid: string;
-    resourceName: string;
-    [key: string]: unknown;
-  };
-};
-
-type ProjectGraphSnapshot = {
-  nodes: GraphNodeLike[];
-  links: GraphLinkLike[];
-  meta: {
-    projectCode: string;
-    projectName: string;
-    [key: string]: unknown;
-  };
-};
-
-function filterGraphData<
-  TNode extends GraphNodeLike,
-  TLink extends GraphLinkLike,
->(input: {
-  nodes: TNode[];
-  links: TLink[];
-  domain?: string;
-  includeLinks?: boolean;
-}) {
-  const requestedDomain = input.domain?.trim().toUpperCase();
-  const nodes = requestedDomain
-    ? input.nodes.filter((node) => node.domain === requestedDomain)
-    : input.nodes;
-  const selectedNodeIds = new Set(nodes.map((node) => node.id));
-  const links = input.includeLinks
-    ? input.links.filter((link) => selectedNodeIds.has(link.source) && selectedNodeIds.has(link.target))
-    : [];
-
-  return {
-    requestedDomain: requestedDomain ?? null,
-    includedLinks: input.includeLinks ?? false,
-    selectedNodeCount: nodes.length,
-    selectedLinkCount: links.length,
-    nodes,
-    ...(input.includeLinks ? { links } : {}),
-  };
-}
-
-function getAvailableDomains<TNode extends { domain: string }>(nodes: TNode[]) {
-  return [...new Set(nodes.map((node) => node.domain))];
-}
-
-function formatResourceGraphDetail(input: {
-  resourceId: string;
-  graph: ResourceGraphSnapshot;
-  domain?: string;
-  includeLinks?: boolean;
-}) {
-  return {
-    resource: {
-      id: input.resourceId,
-      eid: input.graph.meta.resourceEid,
-      displayName: input.graph.meta.resourceName,
-    },
-    availableDomains: getAvailableDomains(input.graph.nodes),
-    totalNodeCount: input.graph.nodes.length,
-    totalLinkCount: input.graph.links.length,
-    ...filterGraphData({
-      nodes: input.graph.nodes,
-      links: input.graph.links,
-      ...(input.domain ? { domain: input.domain } : {}),
-      ...(input.includeLinks !== undefined ? { includeLinks: input.includeLinks } : {}),
-    }),
-    meta: input.graph.meta,
-  };
-}
-
-function formatProjectGraphDetail(input: {
-  projectId: string;
-  graph: ProjectGraphSnapshot;
-  domain?: string;
-  includeLinks?: boolean;
-}) {
-  return {
-    project: {
-      id: input.projectId,
-      shortCode: input.graph.meta.projectCode,
-      name: input.graph.meta.projectName,
-    },
-    availableDomains: getAvailableDomains(input.graph.nodes),
-    totalNodeCount: input.graph.nodes.length,
-    totalLinkCount: input.graph.links.length,
-    ...filterGraphData({
-      nodes: input.graph.nodes,
-      links: input.graph.links,
-      ...(input.domain ? { domain: input.domain } : {}),
-      ...(input.includeLinks !== undefined ? { includeLinks: input.includeLinks } : {}),
-    }),
-    meta: input.graph.meta,
-  };
-}
-
 export function createComputationGraphDetailProcedures(input: {
   resourceGraphInputSchema: z.AnyZodObject;
   projectGraphInputSchema: z.AnyZodObject;