Running custom completion (SCIP) in parallel with TS language server in VS Code

[nakshay]

I’m building an index using SCIP that can provide completions. I’d like to run it alongside the TypeScript language server in VS Code.

The problem:

By default, VS Code always triggers the TS server for completions.

In a very large monorepo, TS server responses are much slower than my SCIP index.

Ideally, I want SCIP completions to appear first in the UI, and then merge in the slower TS completions afterward.

Things I’ve tried:

Using vscode.CompletionItemProvider and merging completions.

Writing a TypeScript language service plugin
, but completions are only provided once the TS server finishes, even with artificial delays.

Question:
Is there any way to run the two providers truly in parallel and surface the faster results first, then merge the slower ones later? Has anyone done something similar?