diff --git a/mintlify-codegen/errors.ts b/mintlify-codegen/errors.ts
index 80d1271c9..0d59f7d50 100644
--- a/mintlify-codegen/errors.ts
+++ b/mintlify-codegen/errors.ts
@@ -282,11 +282,38 @@ function kindSuffix(hasErrors: boolean, hasWarnings: boolean): string {
   return hasErrors ? 'Errors' : 'Warnings'
 }
 
-/** Render the full standalone errors/warnings page (frontmatter + sections). */
+/**
+ * Render a note pointing readers to the errors/warnings shared by all devices.
+ * Device sub-category pages (locks/thermostats/phones) are subsets that omit the
+ * device-level codes (`device_offline`, `device_disconnected`, …) applying to
+ * every device, so a reader troubleshooting connectivity there needs a pointer
+ * to the aggregate device page. `kinds` is the lowercased sections phrase
+ * (`errors and warnings` / `errors` / `warnings`) so the prose matches the
+ * page's actual content.
+ */
+function renderCommonDeviceErrorsNote(
+  noun: string,
+  kinds: string,
+  route: string,
+): string {
+  const phrase = kinds.toLowerCase()
+  return [
+    '<Note>',
+    `  These are ${noun}-specific ${phrase}. For ${phrase} common to all devices, see [Device Errors and Warnings](${route}).`,
+    '</Note>',
+  ].join('\n')
+}
+
+/**
+ * Render the full standalone errors/warnings page (frontmatter + sections). When
+ * `commonDeviceErrorsRoute` is set, a note linking to the shared device
+ * errors/warnings page is prepended — used on device sub-category pages.
+ */
 function renderPage(
   noun: string,
   errorSection: string,
   warningSection: string,
+  commonDeviceErrorsRoute?: string,
 ): string {
   const title = `${noun} ${kindSuffix(Boolean(errorSection), Boolean(warningSection))}`
   const kinds =
@@ -302,7 +329,10 @@ function renderPage(
     `description: '${description.replace(/'/g, "\\'")}'`,
     '---',
   ].join('\n')
-  const body = [errorSection, warningSection].filter(Boolean).join('\n\n')
+  const note = commonDeviceErrorsRoute
+    ? renderCommonDeviceErrorsNote(noun, kinds, commonDeviceErrorsRoute)
+    : ''
+  const body = [note, errorSection, warningSection].filter(Boolean).join('\n\n')
   return `${frontmatter}\n\n${body}\n`
 }
 
@@ -314,6 +344,13 @@ async function readFileOrNull(path: string): Promise<string | null> {
   }
 }
 
+interface ErrorPageOptions {
+  // When set, prepend a note linking to the errors/warnings shared by all
+  // devices. Used only for device sub-category pages (locks/thermostats/phones),
+  // which are subsets that omit the device-level codes.
+  commonDeviceErrorsRoute?: string
+}
+
 /**
  * Write one resource's `errors.mdx` (an `## Errors` and/or `## Warnings`
  * section) and record its route in `routes`. No-ops when the resource has no
@@ -325,7 +362,16 @@ async function writeErrorPage(
   errorsProp: Property | undefined,
   warningsProp: Property | undefined,
   routes: string[],
+  options: ErrorPageOptions = {},
 ): Promise<void> {
+  // Defensive against a variant-group key ever coinciding with a real resource
+  // route: the resource loop writes first, so skip a route already emitted
+  // rather than clobbering it from the sub-category loop.
+  if (routes.includes(routePath)) {
+    console.log(`  Errors page for ${routePath} already written, skipping`)
+    return
+  }
+
   const errorGroups = groupCodes(errorsProp)
   const warningGroups = groupCodes(warningsProp)
   if (errorGroups.length === 0 && warningGroups.length === 0) return
@@ -342,11 +388,24 @@ async function writeErrorPage(
     noun,
     renderSection('Errors', 'error', errorsProp, errorGroups),
     renderSection('Warnings', 'warning', warningsProp, warningGroups),
+    options.commonDeviceErrorsRoute,
   )
   await writeFile(join(resourceDir, 'errors.mdx'), page)
   routes.push(routePath)
 }
 
+interface DeviceSubcategory {
+  // Route that carries the sub-category's dedicated errors page.
+  routePath: string
+  // Whether the sub-category shares the device-level errors/warnings documented
+  // on /api/devices/errors, and so should cross-link to them. The shared codes
+  // are physical-device connectivity/subscription errors (`device_offline`,
+  // `hub_disconnected`, `salto_ks_subscription_limit_exceeded`, …), relevant to
+  // locks and thermostats but not to phones (mobile devices used for
+  // credentials), so the phones page omits the cross-link.
+  linkCommonDeviceErrors: boolean
+}
+
 // Some device sub-categories have their own docs route but no blueprint
 // resource of their own — the Seam API models a lock, thermostat, or phone as a
 // `device`. Their error/warning codes therefore live on the `device` resource
@@ -359,12 +418,17 @@ async function writeErrorPage(
 // but have no standalone sub-category route. In particular /access_codes
 // already documents the `access_code` resource's own, distinct errors — routing
 // the device `access_codes` group there would clobber it.
-const DEVICE_SUBCATEGORY_ERROR_ROUTES: Record<string, string> = {
-  locks: '/locks',
-  phones: '/phones',
-  thermostats: '/thermostats',
+const DEVICE_SUBCATEGORY_ERROR_ROUTES: Record<string, DeviceSubcategory> = {
+  locks: { routePath: '/locks', linkCommonDeviceErrors: true },
+  phones: { routePath: '/phones', linkCommonDeviceErrors: false },
+  thermostats: { routePath: '/thermostats', linkCommonDeviceErrors: true },
 }
 
+// Route of the aggregate device errors/warnings page. Sub-categories that share
+// the device-level codes link back to it (see writeErrorPage's
+// `commonDeviceErrorsRoute` option).
+const COMMON_DEVICE_ERRORS_ROUTE = '/api/devices/errors'
+
 /**
  * Narrow a device `errors`/`warnings` property to a single variant group,
  * flattening the kept variants to ungrouped (`variantGroupKey` cleared) so their
@@ -384,6 +448,58 @@ function variantGroupProp(
   return { ...prop, variants, variantGroups: [] }
 }
 
+/**
+ * Warn when a device errors/warnings variant group looks like it should have its
+ * own sub-category errors page but is missing from DEVICE_SUBCATEGORY_ERROR_ROUTES.
+ *
+ * That allowlist is maintained by hand, so a newly added device sub-category
+ * (its own object + events pages plus an error/warning variant group) would
+ * silently produce no errors page until someone edits the map. This surfaces
+ * that inconsistency at generate time.
+ *
+ * A group is flagged only when it (a) has documented codes, (b) has both an
+ * `object.mdx` and an `events.mdx` under `/api/<key>` — the shape a real
+ * sub-category route has — and (c) is neither already mapped nor itself a
+ * documented blueprint resource. Condition (c) keeps real resources
+ * (`access_codes`, which owns its own distinct errors) and annotation-only
+ * groups (`hardware`, `provider_metadata` — no such route) from tripping it.
+ */
+async function warnUnmappedDeviceSubcategoryGroups(
+  docsDir: string,
+  errorsProp: Property | undefined,
+  warningsProp: Property | undefined,
+  documentedResourceRoutes: Set<string>,
+): Promise<void> {
+  const groupKeys = new Set<string>()
+  for (const prop of [errorsProp, warningsProp]) {
+    if (!isDiscriminatedListProperty(prop)) continue
+    for (const group of prop.variantGroups) groupKeys.add(group.variantGroupKey)
+  }
+
+  for (const groupKey of groupKeys) {
+    if (groupKey in DEVICE_SUBCATEGORY_ERROR_ROUTES) continue
+    if (documentedResourceRoutes.has(`/${groupKey}`)) continue
+
+    const hasCodes =
+      groupCodes(variantGroupProp(errorsProp, groupKey)).length > 0 ||
+      groupCodes(variantGroupProp(warningsProp, groupKey)).length > 0
+    if (!hasCodes) continue
+
+    const resourceDir = join(docsDir, 'api', groupKey)
+    const hasObject =
+      (await readFileOrNull(join(resourceDir, 'object.mdx'))) != null
+    const hasEvents =
+      (await readFileOrNull(join(resourceDir, 'events.mdx'))) != null
+    if (!hasObject || !hasEvents) continue
+
+    console.log(
+      `  WARNING: device errors/warnings variant group "${groupKey}" has codes ` +
+        `and an object+events page (/api/${groupKey}) but no dedicated errors ` +
+        `page. Add it to DEVICE_SUBCATEGORY_ERROR_ROUTES in mintlify-codegen/errors.ts.`,
+    )
+  }
+}
+
 /**
  * Generate the per-resource `errors.mdx` pages. Returns the route paths that
  * received a page (e.g. `/devices`) so the caller can wire them into the
@@ -413,17 +529,35 @@ export async function updateErrorPages(
   if (device != null) {
     const errorsProp = device.properties.find((p) => p.name === 'errors')
     const warningsProp = device.properties.find((p) => p.name === 'warnings')
-    for (const [groupKey, routePath] of Object.entries(
-      DEVICE_SUBCATEGORY_ERROR_ROUTES,
-    )) {
+    for (const [
+      groupKey,
+      { routePath, linkCommonDeviceErrors },
+    ] of Object.entries(DEVICE_SUBCATEGORY_ERROR_ROUTES)) {
       await writeErrorPage(
         docsDir,
         routePath,
         variantGroupProp(errorsProp, groupKey),
         variantGroupProp(warningsProp, groupKey),
         routes,
+        linkCommonDeviceErrors
+          ? { commonDeviceErrorsRoute: COMMON_DEVICE_ERRORS_ROUTE }
+          : {},
       )
     }
+
+    // Flag any device sub-category that has its own object+events pages and
+    // error codes but was never added to the allowlist above.
+    const documentedResourceRoutes = new Set(
+      blueprint.resources
+        .filter((r) => !r.isUndocumented)
+        .map((r) => r.routePath),
+    )
+    await warnUnmappedDeviceSubcategoryGroups(
+      docsDir,
+      errorsProp,
+      warningsProp,
+      documentedResourceRoutes,
+    )
   }
 
   return routes
diff --git a/mintlify-docs/api/locks/errors.mdx b/mintlify-docs/api/locks/errors.mdx
index 3ab463a6f..cad40bcd9 100644
--- a/mintlify-docs/api/locks/errors.mdx
+++ b/mintlify-docs/api/locks/errors.mdx
@@ -3,6 +3,10 @@ title: 'Lock Errors and Warnings'
 description: 'Errors and warnings that Seam reports on the Lock resource, each with its code and meaning.'
 ---
 
+<Note>
+  These are Lock-specific errors and warnings. For errors and warnings common to all devices, see [Device Errors and Warnings](/api/devices/errors).
+</Note>
+
 ## Errors
 
 Each error is an object with the following shape:
diff --git a/mintlify-docs/api/thermostats/errors.mdx b/mintlify-docs/api/thermostats/errors.mdx
index 6d6e9357f..bd0c0837c 100644
--- a/mintlify-docs/api/thermostats/errors.mdx
+++ b/mintlify-docs/api/thermostats/errors.mdx
@@ -3,6 +3,10 @@ title: 'Thermostat Errors and Warnings'
 description: 'Errors and warnings that Seam reports on the Thermostat resource, each with its code and meaning.'
 ---
 
+<Note>
+  These are Thermostat-specific errors and warnings. For errors and warnings common to all devices, see [Device Errors and Warnings](/api/devices/errors).
+</Note>
+
 ## Errors
 
 Each error is an object with the following shape: