diff --git a/docs/user/generated_config.adoc b/docs/user/generated_config.adoc
index db41c7bf10..f59a524364 100644
--- a/docs/user/generated_config.adoc
+++ b/docs/user/generated_config.adoc
@@ -604,6 +604,11 @@ Number of syntax trees rust-analyzer keeps in memory. Defaults to 128.
 --
 Whether to show `can't find Cargo.toml` error message.
 --
+[[rust-analyzer.numThreads]]rust-analyzer.numThreads (default: `null`)::
++
+--
+How many worker threads in the main loop. The default `null` means to pick automatically.
+--
 [[rust-analyzer.procMacro.attributes.enable]]rust-analyzer.procMacro.attributes.enable (default: `true`)::
 +
 --
diff --git a/editors/code/package.json b/editors/code/package.json
index ad5f97bb19..26a1e81f13 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -1137,6 +1137,15 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.numThreads": {
+                    "markdownDescription": "How many worker threads in the main loop. The default `null` means to pick automatically.",
+                    "default": null,
+                    "type": [
+                        "null",
+                        "integer"
+                    ],
+                    "minimum": 0
+                },
                 "rust-analyzer.procMacro.attributes.enable": {
                     "markdownDescription": "Expand attribute macros. Requires `#rust-analyzer.procMacro.enable#` to be set.",
                     "default": true,