diff --git a/src/clients/core.ts b/src/clients/core.ts
index 3002314..92122ea 100644
--- a/src/clients/core.ts
+++ b/src/clients/core.ts
@@ -157,6 +157,32 @@ export async function setSimulatorUrl(
 	}
 }
 
+const DocumentSearchTotalSchema = z.object({
+	total: z.number(),
+});
+
+export async function getDocumentTotalByCustomTypes(
+	customTypeId: string,
+	config: { repo: string; token: string | undefined; host: string },
+): Promise<number> {
+	const { repo, token, host } = config;
+	const url = new URL("core/documents/search", getCoreBaseUrl(repo, host));
+	try {
+		const response = await request(url, {
+			method: "POST",
+			body: { customTypes: [customTypeId], limit: 0 },
+			credentials: { "prismic-auth": token },
+			schema: DocumentSearchTotalSchema,
+		});
+		return response.total;
+	} catch (error) {
+		if (error instanceof NotFoundRequestError) {
+			error.message = `Repository not found: ${repo}`;
+		}
+		throw error;
+	}
+}
+
 function getCoreBaseUrl(repo: string, host: string): URL {
 	return new URL(`https://${repo}.${host}/`);
 }
diff --git a/src/clients/wroom.ts b/src/clients/wroom.ts
index 408b5f0..de1ce41 100644
--- a/src/clients/wroom.ts
+++ b/src/clients/wroom.ts
@@ -421,3 +421,26 @@ function getDashboardUrl(host: string): URL {
 function getWroomUrl(repo: string, host: string): URL {
 	return new URL(`https://${repo}.${host}/`);
 }
+
+/** Editor parity: document list filtered by custom type (sidebar / working view). */
+export function getWorkingDocumentsUrlForCustomType(
+	args: { repo: string; host: string; customTypeId: string },
+): string {
+	const { repo, host, customTypeId } = args;
+	const url = new URL("builder/working", getWroomUrl(repo, host));
+	url.searchParams.set("customTypes", customTypeId);
+	return url.href;
+}
+
+type GetCustomTypePagesUrlArgs = {
+	repo: string;
+	host: string;
+	format: "custom" | "page";
+};
+
+export function getCustomTypeListUrl(args: GetCustomTypePagesUrlArgs): string {
+	const { repo, host, format } = args;
+	const path = ["builder", "types", format === "custom" ? "custom-types" : "page-types"].join("/");
+	const url = new URL(path, getWroomUrl(repo, host));
+	return url.href;
+}
\ No newline at end of file
diff --git a/src/commands/push.ts b/src/commands/push.ts
index 485b84a..7fb3871 100644
--- a/src/commands/push.ts
+++ b/src/commands/push.ts
@@ -1,7 +1,10 @@
 import { pascalCase } from "change-case";
 
+import type { CustomType } from "@prismicio/types-internal/lib/customtypes";
+
 import { getAdapter } from "../adapters";
 import { getHost, getToken } from "../auth";
+import { getDocumentTotalByCustomTypes } from "../clients/core";
 import {
 	getCustomTypes,
 	getSlices,
@@ -16,10 +19,12 @@ import {
 	completeOnboardingStepsSilently,
 	type OnboardingStep,
 } from "../clients/repository";
+import { getWorkingDocumentsUrlForCustomType, getCustomTypeListUrl } from "../clients/wroom";
 import { resolveEnvironment } from "../environments";
 import { CommandError, createCommand, type CommandConfig } from "../lib/command";
 import { diffArrays } from "../lib/diff";
 import { getDirtyPaths, getGitRoot } from "../lib/git";
+import { BadRequestError } from "../lib/request";
 import { appendTrailingSlash, isDescendant, relativePathname } from "../lib/url";
 import { canonicalizeModel } from "../models";
 import { findProjectRoot, getRepositoryName } from "../project";
@@ -134,8 +139,8 @@ export default createCommand(config, async ({ values }) => {
 	for (const model of customTypeOps.update) {
 		await updateCustomType(model, { repo, token, host });
 	}
-	for (const id of customTypeOps.delete.map((m) => m.id)) {
-		await removeCustomType(id, { repo, token, host });
+	for (const model of customTypeOps.delete) {
+		await removeCustomTypeWithDocumentHandling(model, { repo, token, host });
 	}
 	for (const model of sliceOps.insert) {
 		await insertSlice(model, { repo, token, host });
@@ -173,3 +178,53 @@ export default createCommand(config, async ({ values }) => {
 		if (totalDeletes > 0) console.info(`Deleted ${totalDeletes} model(s).`);
 	}
 });
+
+async function removeCustomTypeWithDocumentHandling(
+	model: CustomType,
+	config: {
+		repo: string;
+		token: string | undefined;
+		host: string;
+	},
+): Promise<void> {
+	const { repo, token, host } = config;
+	const { id, format } = model;
+
+	try {
+		await removeCustomType(id, { repo, token, host });
+	} catch (error) {
+		if (!(await isDocumentsInUseError(error))) {
+			const errorMessage = error instanceof Error ? error.message : String(error);
+			throw new CommandError(
+				`Could not delete type "${id}": ${errorMessage}"` + 
+					"\nPlease try again, or manually deleting the type at: " + 
+					getCustomTypeListUrl({ repo, host, format: format ?? "custom" })
+			);
+		}
+
+		let documentCount: number;
+		try {
+			documentCount = await getDocumentTotalByCustomTypes(id, { repo, token, host });
+		} catch {
+			throw new CommandError(
+				`Could not check whether type "${id}" has associated pages. ` +
+					"\nPlease try again, or manually delete any associated pages at: " + 
+					getWorkingDocumentsUrlForCustomType({ repo, host, customTypeId: id }),
+			);
+		}
+
+		const countLabel = documentCount > 0 ? ` ${documentCount}` : "";
+		const pluralPages = documentCount === 1 ? "page" : "pages";
+		throw new CommandError(
+			`Could not delete type "${id}" because it has${countLabel} associated ${pluralPages}. ` +
+				`\nDelete any associated pages manually before pushing at: ` + 
+				getWorkingDocumentsUrlForCustomType({ repo, host, customTypeId: id }),
+		);
+	}
+}
+
+async function isDocumentsInUseError(error: unknown): Promise<boolean> {
+	if (!(error instanceof BadRequestError)) return false;
+	const body = await error.text();
+	return body.includes("associated documents") || body.includes("Delete all documents belonging");
+}
diff --git a/src/lib/request.ts b/src/lib/request.ts
index f9c63ad..b645916 100644
--- a/src/lib/request.ts
+++ b/src/lib/request.ts
@@ -53,6 +53,7 @@ export async function request<T>(
 
 		return value;
 	} else {
+		if (response.status === 400) throw new BadRequestError(response, value);
 		if (response.status === 401) throw new UnauthorizedRequestError(response);
 		if (response.status === 403) throw new ForbiddenRequestError(response);
 		if (response.status === 404) throw new NotFoundRequestError(response);
@@ -89,6 +90,15 @@ export class RequestError extends Error {
 export class UnknownRequestError extends RequestError {
 	name = "UnknownRequestError";
 }
+export class BadRequestError extends RequestError {
+	name = "BadRequestError";
+	body: unknown;
+
+	constructor(response: Response, body: unknown) {
+		super(response);
+		this.body = body;
+	}
+}
 export class NotFoundRequestError extends RequestError {
 	name = "NotFoundRequestError";