diff --git a/apps/server/src/api-mcp/mcp.prompts.ts b/apps/server/src/api-mcp/mcp.prompts.ts
index e82539b29..006c926dd 100644
--- a/apps/server/src/api-mcp/mcp.prompts.ts
+++ b/apps/server/src/api-mcp/mcp.prompts.ts
@@ -33,6 +33,17 @@ export const PROMPT_DEFINITIONS: ListPromptsResult['prompts'] = [
       },
     ],
   },
+  {
+    name: 'manage_custom_fields',
+    description: 'List, create, rename, recolour, or delete project-level custom field definitions',
+    arguments: [
+      {
+        name: 'instruction',
+        description: 'What to do, e.g. "add a Speaker field" or "delete the Camera field"',
+        required: true,
+      },
+    ],
+  },
 ];
 
 function userPrompt(description: string, text: string): GetPromptResult {
@@ -203,5 +214,36 @@ Efficiency tip: plan moves in the direction of the target position to minimise r
     );
   }
 
+  if (name === 'manage_custom_fields') {
+    return userPrompt(
+      'List, create, rename, recolour, or delete custom field definitions',
+      `Manage the project-level custom field definitions for this Ontime project: "${args.instruction}"
+
+Custom fields are project-scoped. They appear as columns in the cuesheet and can be set on any event, milestone, or group. Changes apply to all rundowns in the project.
+
+Steps:
+1. Call ontime_get_custom_fields to see what fields already exist. This is mandatory before creating — to avoid duplicates such as "Cam", "camera", and "Cameras".
+2. Carry out the instruction using the tools below. Confirm destructive changes (rename, delete) with the user before calling.
+
+Creating a field:
+- Call ontime_create_custom_field with { label, type, colour }.
+- label: human-readable name (alphanumeric with spaces). The key is auto-derived: spaces → underscores (e.g. "Camera Angle" → "Camera_Angle"). Confirm the derived key with the user before creating.
+- type: "text" for short string values, "image" for image URLs. Cannot be changed after creation.
+- colour: hex colour (#RRGGBB) used to visually identify this column in the cuesheet. Ask the user what colour to use if not specified.
+- Returns: { key, customFields } — use the returned key when setting values on entries.
+
+Renaming or recolouring a field:
+- Call ontime_update_custom_field with { key, label?, colour? }.
+- Warning: changing the label changes the derived key and cascades to all entry references in all rundowns. Confirm with the user before renaming.
+- The field type cannot be changed.
+
+Deleting a field:
+- Call ontime_delete_custom_field with { key }.
+- Warning: this permanently removes the field definition and its values from every entry in all rundowns. Confirm with the user before deleting.
+
+After any mutation, call ontime_get_custom_fields again to confirm the result and show the user the updated field list with their keys.`,
+    );
+  }
+
   throw new Error(`Unknown prompt: ${name}`);
 }
diff --git a/apps/server/src/api-mcp/mcp.schema.ts b/apps/server/src/api-mcp/mcp.schema.ts
index b5d32b7ee..131c27de6 100644
--- a/apps/server/src/api-mcp/mcp.schema.ts
+++ b/apps/server/src/api-mcp/mcp.schema.ts
@@ -177,8 +177,15 @@ Examples:
 ## Custom fields
 Custom fields are project-scoped definitions. Get definitions at \`ontime://project/custom-fields\` or with \`ontime_get_custom_fields\`.
 Events, milestones and groups store values at \`entry.custom[fieldKey]\`.
-Only use existing field keys when setting \`custom\` values. Adding, renaming, or deleting custom field definitions is a separate project-level operation.
-When the user wants to assign custom values, show the existing custom field list first if there is any ambiguity, so you do not create duplicate concepts such as \`Cam\`, \`camera\`, and \`Cameras\`.
+
+Managing field definitions:
+- Read: \`ontime_get_custom_fields\` — returns \`{ [key]: { label, type, colour } }\`
+- Create: \`ontime_create_custom_field { label, type, colour }\` — key is auto-derived from label (spaces → underscores). Confirm the derived key before creating. Returns \`{ key, customFields }\`.
+- Rename/recolour: \`ontime_update_custom_field { key, label?, colour? }\` — renaming the label changes the derived key and cascades to all entry references across all rundowns. Type cannot be changed.
+- Delete: \`ontime_delete_custom_field { key }\` — removes the field definition and its values from every entry in all rundowns. Destructive, confirm first.
+
+When setting \`custom\` values on entries, only use existing field keys. If a key does not exist, create it with \`ontime_create_custom_field\` first.
+Show the existing field list before creating to avoid duplicates such as \`Cam\`, \`camera\`, and \`Cameras\`.
 
 ## Targeting rundowns
 Entry read/write tools accept an optional \`rundownId\`.
diff --git a/apps/server/src/api-mcp/mcp.service.ts b/apps/server/src/api-mcp/mcp.service.ts
index 9b4a25dd2..892013f80 100644
--- a/apps/server/src/api-mcp/mcp.service.ts
+++ b/apps/server/src/api-mcp/mcp.service.ts
@@ -17,7 +17,10 @@ import { getCurrentRundown, getCurrentRundownId, getProjectCustomFields } from '
 import {
   addEntry,
   batchEditEntries,
+  createCustomField,
+  deleteCustomField,
   deleteEntries,
+  editCustomField,
   editEntry,
   groupEntries,
   reorderEntry,
@@ -103,8 +106,15 @@ export function assertKnownCustomFields(...customValues: Array<EntryFieldArgs['c
   }
 
   if (unknownKeys.size > 0) {
-    const keys = [...unknownKeys].join(', ');
-    throw new Error(`Unknown custom field key(s): ${keys}. Call ontime_get_custom_fields to list available keys.`);
+    const missing = [...unknownKeys].join(', ');
+    const available = Object.keys(customFields);
+    const hint = available.length > 0 ? `Available keys: ${available.join(', ')}.` : 'No custom fields are defined yet.';
+    throw new Error(
+      `Unknown custom field key(s): ${missing}. ${hint} ` +
+        `Call ontime_create_custom_field with { label, type, colour } to create a missing field — ` +
+        `the key is auto-derived from the label (spaces → underscores, e.g. label "Camera" → key "Camera"). ` +
+        `Call ontime_get_custom_fields to list existing keys.`,
+    );
   }
 }
 
@@ -320,3 +330,21 @@ export async function batchUpdateEntriesForMcp(args: TargetRundownArgs & { ids:
   const rundown = await batchEditEntries(rundownId, args.ids, args.data);
   return { target: getTargetMeta(rundownId), updated: args.ids, order: rundown.order };
 }
+
+export async function createCustomFieldForMcp(args: { label: string; type: 'text' | 'image'; colour: string }) {
+  const updated = await createCustomField({ label: args.label, type: args.type, colour: args.colour });
+  const key = Object.keys(updated).find((k) => updated[k].label === args.label) ?? args.label;
+  return { key, customFields: updated };
+}
+
+export async function updateCustomFieldForMcp(args: { key: string; label?: string; colour?: string }) {
+  const projectRundowns = getDataProvider().getProjectRundowns();
+  const updated = await editCustomField(args.key, { label: args.label, colour: args.colour }, projectRundowns);
+  return { customFields: updated };
+}
+
+export async function deleteCustomFieldForMcp(args: { key: string }) {
+  const projectRundowns = getDataProvider().getProjectRundowns();
+  const updated = await deleteCustomField(args.key, projectRundowns);
+  return { customFields: updated };
+}
diff --git a/apps/server/src/api-mcp/mcp.tools.ts b/apps/server/src/api-mcp/mcp.tools.ts
index 03bd3ea78..e629a5fc7 100644
--- a/apps/server/src/api-mcp/mcp.tools.ts
+++ b/apps/server/src/api-mcp/mcp.tools.ts
@@ -25,7 +25,9 @@ import { EVENT_WRITABLE_FIELDS, RUNDOWN_TARGET_FIELD } from './mcp.schema.js';
 import {
   batchCreateEntriesForMcp,
   batchUpdateEntriesForMcp,
+  createCustomFieldForMcp,
   createEntryForMcp,
+  deleteCustomFieldForMcp,
   deleteEntriesForMcp,
   findEntry,
   getRundownById,
@@ -33,6 +35,7 @@ import {
   reorderEntryForMcp,
   toRundownList,
   ungroupEntryForMcp,
+  updateCustomFieldForMcp,
   updateEntryForMcp,
   type BatchCreateEntryArgs,
   type CreateEntryArgs,
@@ -371,6 +374,60 @@ export const TOOL_DEFINITIONS = [
     inputSchema: { type: 'object', properties: {} },
     annotations: READ,
   },
+  {
+    name: 'ontime_create_custom_field',
+    description:
+      'Create a new project-level custom field definition. Custom fields add typed columns to every entry in all rundowns. The key is auto-derived from the label (spaces → underscores, e.g. "Camera Angle" → "Camera_Angle"). After creation, use the key in entry.custom when creating or updating entries.',
+    inputSchema: {
+      type: 'object',
+      required: ['label', 'type', 'colour'],
+      properties: {
+        label: {
+          type: 'string',
+          description:
+            'Human-readable label (alphanumeric with spaces, e.g. "Camera"). Determines the key — ask the user to confirm before creating to avoid duplicates like "Cam", "camera", "Cameras".',
+        },
+        type: {
+          type: 'string',
+          enum: ['text', 'image'],
+          description: 'Field type — cannot be changed after creation. Use "text" for short text values; "image" for image URLs.',
+        },
+        colour: {
+          type: 'string',
+          description: 'Hex colour (#RRGGBB) used to visually identify this column in the cuesheet.',
+        },
+      },
+    },
+    annotations: WRITE,
+  },
+  {
+    name: 'ontime_update_custom_field',
+    description:
+      'Update a custom field label or colour. Changing the label renames the derived key (spaces → underscores) and updates all entry references across all rundowns. Field type cannot be changed.',
+    inputSchema: {
+      type: 'object',
+      required: ['key'],
+      properties: {
+        key: { type: 'string', description: 'Current field key (from ontime_get_custom_fields)' },
+        label: { type: 'string', description: 'New human-readable label (optional). Changes the derived key and cascades to all entries.' },
+        colour: { type: 'string', description: 'New hex colour (#RRGGBB) (optional)' },
+      },
+    },
+    annotations: WRITE_IDEM,
+  },
+  {
+    name: 'ontime_delete_custom_field',
+    description:
+      'Delete a custom field definition and remove its values from all entries in all rundowns. Destructive and cannot be undone — confirm with the user before calling.',
+    inputSchema: {
+      type: 'object',
+      required: ['key'],
+      properties: {
+        key: { type: 'string', description: 'Field key to delete (from ontime_get_custom_fields)' },
+      },
+    },
+    annotations: WRITE_DESTRUCTIVE,
+  },
   // --- Project file management ---
   {
     name: 'ontime_list_projects',
@@ -571,6 +628,18 @@ const TOOL_HANDLERS: Record<ToolName, (args: Record<string, unknown>) => Promise
 
   ontime_get_custom_fields: async () => ok(getProjectCustomFields()),
 
+  ontime_create_custom_field: async (args) => {
+    return ok(await createCustomFieldForMcp(args as { label: string; type: 'text' | 'image'; colour: string }));
+  },
+
+  ontime_update_custom_field: async (args) => {
+    return ok(await updateCustomFieldForMcp(args as { key: string; label?: string; colour?: string }));
+  },
+
+  ontime_delete_custom_field: async (args) => {
+    return ok(await deleteCustomFieldForMcp(args as { key: string }));
+  },
+
   ontime_list_projects: async () => ok(await getProjectList()),
 
   ontime_load_project: async (args) => {