fix(build): stop tsc packages from no-op'ing their own emit

Adding four modules to @loopover/contract produced a GREEN `@loopover/contract:build` in
CI followed five seconds later, on the same runner, by
`Cannot find module '@loopover/contract/local-config'` from the miner's build.

`tsc -p` with `incremental` (inherited from the root tsconfig) decides what to emit from
.tsbuildinfo alone -- it never checks whether the outputs that stamp describes are still
on disk. turbo caches .tsbuildinfo alongside dist/, so a run where the two come back out
of lockstep, or a --force run over a leftover stamp, makes tsc declare itself up to date
and emit nothing. Reproduced exactly by deleting dist/ with the stamp left in place.

All three packages that cache .tsbuildinfo as a turbo output have the same exposure, so
each clears the stamp before compiling; any new file in any of them could have hit this.

The UI preview workflow separately never built the contract at all -- it builds the engine
and then runs ui:openapi, which now reaches src/openapi/schemas.ts's re-export of the
public-API schemas. It builds both packages now.

package-lock.json was out of sync with two real changes: the contract's new
@cloudflare/workers-types devDependency and the UI's new @loopover/contract dependency.

Author: JSONbored

.github/workflows/ui-preview.yml

@@ -79,6 +79,10 @@ jobs:
       # away the result. `npx turbo run build --filter=@loopover/ui` replaces the last two `ui:build`
       # steps (`extension:build && miner-extension:build && ui build` already covered by
       # @loopover/ui#build's own turbo.json dependsOn) and skips ui-miner entirely.
+      # @loopover/contract joins the engine filter because `ui:openapi` imports src/openapi/schemas.ts,
+      # which re-exports the public-API response schemas from @loopover/contract/public-api (#9282/#9521).
+      # Without it this step failed with ERR_MODULE_NOT_FOUND on dist/public-api.js -- the contract was
+      # never built here at all, only in the CI workflow's own steps.
       - name: Build UI
         env:
           VITE_LOOPOVER_API_ORIGIN: https://api.loopover.ai
@@ -87,7 +91,7 @@ jobs:
           # production build (ui-deploy.yml) does NOT set this, so the escape hatch is dead-code-eliminated
           # from prod. (#authed-route-preview)
           VITE_PREVIEW: "1"
-        run: npm run ui:kit:build && npx turbo run build --filter=@loopover/engine && npm run ui:openapi && npx turbo run build --filter=@loopover/ui
+        run: npm run ui:kit:build && npx turbo run build --filter=@loopover/engine --filter=@loopover/contract && npm run ui:openapi && npx turbo run build --filter=@loopover/ui
 
       # Deploys stay best-effort when the Cloudflare secrets aren't configured (Reviewbot shows
       # before-only) — mirrors ui-preview-deploy.yml's guard.
@@ -177,7 +181,7 @@ jobs:
         env:
           VITE_LOOPOVER_API_ORIGIN: https://api.loopover.ai
           VITE_PREVIEW: "1"
-        run: npm run ui:kit:build && npx turbo run build --filter=@loopover/engine && npm run ui:openapi && npx turbo run build --filter=@loopover/ui
+        run: npm run ui:kit:build && npx turbo run build --filter=@loopover/engine --filter=@loopover/contract && npm run ui:openapi && npx turbo run build --filter=@loopover/ui
 
       # The trusted deploy workflow downloads this by name + run-id. It contains only the built bundle
       # (server/ + client/) — no secrets, no source needed downstream.

package-lock.json

@@ -66,7 +66,7 @@
     "CHANGELOG.md"
   ],
   "scripts": {
-    "build": "tsc -p tsconfig.json"
+    "build": "node -e \"require('node:fs').rmSync('.tsbuildinfo',{force:true})\" && tsc -p tsconfig.json"
   },
   "dependencies": {
     "zod": "^4.4.3"

packages/loopover-contract/package.json

@@ -41,7 +41,7 @@
   ],
   "scripts": {
     "build": "npm run build:tsc && npm run build:verify",
-    "build:tsc": "tsc -p tsconfig.json && node --experimental-strip-types scripts/strip-bin-sourcemap.ts",
+    "build:tsc": "node -e \"require('node:fs').rmSync('.tsbuildinfo',{force:true})\" && tsc -p tsconfig.json && node --experimental-strip-types scripts/strip-bin-sourcemap.ts",
     "build:verify": "node --experimental-strip-types scripts/check-syntax.ts"
   },
   "dependencies": {

packages/loopover-mcp/package.json

@@ -43,7 +43,7 @@
     "benchmark": "node --experimental-strip-types scripts/benchmark.ts",
     "cross-repo-eval": "node --experimental-strip-types scripts/cross-repo-evaluation.ts",
     "build": "npm run build:tsc && npm run build:verify",
-    "build:tsc": "tsc -p tsconfig.json",
+    "build:tsc": "node -e \"require('node:fs').rmSync('.tsbuildinfo',{force:true})\" && tsc -p tsconfig.json",
     "build:verify": "node --experimental-strip-types scripts/check-syntax.ts"
   },
   "dependencies": {

packages/loopover-miner/package.json

@@ -0,0 +1,42 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+
+// REGRESSION (#9521): a package whose build is `tsc -p` with `incremental` (inherited from the root
+// tsconfig) decides what to emit from `.tsbuildinfo` ALONE — it never checks whether the outputs it
+// describes are still on disk. turbo caches `.tsbuildinfo` alongside `dist/`, so any run where the two come
+// back out of lockstep (or a `--force` run over a leftover stamp) makes tsc declare itself up to date and
+// emit NOTHING, leaving `dist/` without the new files.
+//
+// That is not hypothetical: adding four modules to @loopover/contract produced a green
+// `@loopover/contract:build` in CI followed immediately by
+// `Cannot find module '@loopover/contract/local-config'` from the miner's own build, on the same runner,
+// five seconds apart. Every package that caches `.tsbuildinfo` as a turbo output has the same exposure, so
+// each of them deletes the stamp before building.
+
+const PACKAGES_CACHING_TSBUILDINFO = ["loopover-contract", "loopover-mcp", "loopover-miner"] as const;
+
+function buildScript(pkg: string): string {
+  const manifest = JSON.parse(readFileSync(join(process.cwd(), `packages/${pkg}/package.json`), "utf8")) as {
+    scripts: Record<string, string>;
+  };
+  return manifest.scripts["build:tsc"] ?? manifest.scripts.build!;
+}
+
+describe("tsc packages cannot no-op their own emit (#9521)", () => {
+  it.each(PACKAGES_CACHING_TSBUILDINFO)("%s clears .tsbuildinfo before compiling", (pkg) => {
+    const script = buildScript(pkg);
+    expect(script, `${pkg}'s build must not trust a stale incremental stamp`).toContain(".tsbuildinfo");
+    // The clear must come FIRST — after tsc it would defeat the purpose entirely.
+    expect(script.indexOf(".tsbuildinfo"), `${pkg} must clear the stamp before tsc runs`).toBeLessThan(script.indexOf("tsc -p"));
+  });
+
+  it("names every package that caches .tsbuildinfo as a turbo output — a new one must be added here", () => {
+    const turbo = readFileSync(join(process.cwd(), "turbo.json"), "utf8");
+    // Strip comments; turbo.json is JSONC and the comments themselves mention .tsbuildinfo.
+    const withoutComments = turbo.replace(/^\s*\/\/.*$/gm, "");
+    const tasks = [...withoutComments.matchAll(/"(@loopover\/[a-z-]+)#build(?::tsc)?":\s*\{[^}]*?"outputs":\s*\[([^\]]*)\]/gs)];
+    const caching = tasks.filter(([, , outputs]) => outputs!.includes(".tsbuildinfo")).map(([, name]) => name!.replace("@loopover/", "loopover-"));
+    expect(caching.sort()).toEqual([...PACKAGES_CACHING_TSBUILDINFO].sort());
+  });
+});