## Problem
Three Sentry issues, all `Missing requestHandler or method: <method>`,
first seen in v2.27.0:
| Method | Page | Events |
|---|---|---|
| `findDocumentColors` | `/settings/mcp-apis` | 170 |
| `resetSchema` | `/settings/mcp-apis` | 22 |
| `getCodeFixesAtPosition` | `/object/workflow/…` | 4 |
The first two are Monaco **JSON worker** methods, the third a
**TypeScript worker** method. All of them bottom out in
`monaco-editor/esm/vs/editor/common/services/editorSimpleWorker.js` at
`$fmr` — the foreign-module dispatcher — with `_foreignModule` still
`null`.
## Root cause
Two Monaco copies end up on the page at **different versions**:
1. **ESM `monaco-editor@0.52.2`**, bundled by Vite — what GraphiQL 5
uses.
2. **AMD `monaco-editor@0.55.1` from jsDelivr** — `@monaco-editor/react`
→ `@monaco-editor/loader@1.7.0`, whose default CDN path is hardcoded to
`monaco-editor@0.55.1/min/vs`. Nothing calls `loader.config({ monaco
})`, so it goes to the CDN.
`setupGraphiqlMonacoWorkers.ts` assigns
**`globalThis.MonacoEnvironment`**, a single global both instances read,
as a module side effect of the lazily-routed `GraphQLPlayground`. So
once the playground has been opened, the 0.55.1 CDN instance stops using
its own AMD workers and starts getting Vite-bundled 0.52.2 ones.
The two versions don't share a worker protocol: 0.52 routes
language-service calls through `$loadForeignModule` + `$fmr`, which
0.55's client never sends. `_foreignModule` stays `null`, and every call
rejects.
On `/settings/mcp-apis` the consumer is `SettingsMcpSetup.tsx` —
`<CodeEditor language="json">` for the MCP config. Monaco fires
`resetSchema` on `onWillDisposeModel` / `onDidChangeModelLanguage` and
`findDocumentColors` continuously, which is why one bug produces 170
events and 22.
There is a second, independent bug in the same file: the `switch` only
maps `json` and `graphql`, so `typescript` / `javascript` / `css` /
`html` fall through to the bare `EditorWorker`, which carries no
language service at all. That's the workflow-page
`getCodeFixesAtPosition`, and it would break even with matching
versions.
Impact is worse than the log noise suggests: after visiting the
playground, JSON validation/colors in the MCP config editor and TS
intellisense/quick-fixes in the workflow code editor silently stop
working for the rest of the session.
## Changes
- **`twenty-ui/src/input/CodeEditor/CodeEditor.tsx`** — configure
`@monaco-editor/react` with the bundled Monaco (`loader.config({ monaco
})`) instead of letting it fetch its own from jsDelivr. The import stays
dynamic so Monaco is still only downloaded when an editor actually
renders; the component shows its existing `Loader` until the loader is
configured.
- **`twenty-front/src/modules/app/utils/setupMonacoEnvironment.ts`**
(new, replaces
`settings/mcp-and-apis/utils/setupGraphiqlMonacoWorkers.ts`) — app-level
worker factory mapping every label Monaco can ask for: `json`,
`css`/`scss`/`less`, `html`/`handlebars`/`razor`,
`typescript`/`javascript`, `graphql`, and the generic editor worker as
the fallback.
- **`twenty-front/src/index.tsx`** and **`.storybook/preview.tsx`** —
set it up once for the app and for stories, rather than as a side effect
of one lazy route.
Dropping the CDN also means the code editors work in self-hosted and
air-gapped deployments, which today silently fall back to a broken
editor when jsDelivr is unreachable.
## Verification
- `nx build twenty-front` passes; `css.worker`, `html.worker` and
`ts.worker` chunks are now emitted alongside the existing
`editor`/`json`/`graphql` ones.
- Monaco stays lazy — `edcore.main` is not statically imported by the
entry chunk and is absent from `index.html`'s modulepreloads. Measured
against a baseline build of `main`, the entry chunk goes from 2,598,088
B to 2,599,040 B (**+952 B**).
- `oxlint` and `oxfmt --check` clean on all touched files; `tsc
--noEmit` clean for `twenty-ui` and reports nothing new for the touched
`twenty-front` files.
Not verified in a browser — worth a manual pass on the playground → MCP
tab → workflow code editor sequence that reproduced the original errors.
Fixes TWENTY-FRONT-8YV
Fixes TWENTY-FRONT-8YW
Fixes TWENTY-FRONT-ADE
---
_Generated by [Claude
Code](https://claude.ai/code/session_01RgPXkmUHANwD7ooUMqNYr9)_
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Félix Malfait
f4d5500fc4
