feat: support an explicit start command override per installation

Needed to install third-party repos we don't control (e.g. the
upstream gitea.com/gitea/gitea-mcp project) where nixpacks detects a
working build but the wrong/no start command, and pushing a
nixpacks.toml to the source repo isn't an option. Passed through as
nixpacks' own --start-cmd flag.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/server/src/api/installations.ts

@@ -58,7 +58,8 @@ installationsRouter.post("/", async (req, res) => {
 });
 
 installationsRouter.patch("/:id/config", (req, res) => {
-  const { env, portEnvVar, hostEnvVar, httpPath, internalPort, basicAuthUsername, basicAuthPassword } = req.body ?? {};
+  const { env, portEnvVar, hostEnvVar, httpPath, internalPort, basicAuthUsername, basicAuthPassword, startCommand } =
+    req.body ?? {};
   try {
     const installation = configureInstallation(req.params.id, {
       env,
@@ -68,6 +69,7 @@ installationsRouter.patch("/:id/config", (req, res) => {
       internalPort,
       basicAuthUsername,
       basicAuthPassword,
+      startCommand,
     });
     res.json(toPublicJson(installation));
   } catch (err) {

apps/server/src/build/nixpacks.ts

@@ -54,7 +54,12 @@ export function detectNodeVersion(repoDir: string): string | undefined {
   return DEFAULT_NODE_VERSION;
 }
 
-export function runNixpacksBuild(slug: string, repoDir: string, imageTag: string): Promise<BuildResult> {
+export function runNixpacksBuild(
+  slug: string,
+  repoDir: string,
+  imageTag: string,
+  startCommand?: string | null,
+): Promise<BuildResult> {
   return new Promise((resolve) => {
     const buildId = Date.now().toString();
     const logPath = buildLogPath(slug, buildId);
@@ -62,6 +67,13 @@ export function runNixpacksBuild(slug: string, repoDir: string, imageTag: string
     const logStream = fs.createWriteStream(logPath, { flags: "a" });
 
     const args = ["build", repoDir, "--name", imageTag];
+    if (startCommand) {
+      // Lets an installation override the start command without needing a nixpacks.toml in
+      // the source repo — necessary for third-party repos we don't control (e.g. installing
+      // gitea.com/gitea/gitea-mcp as-is, which nixpacks builds fine but whose detected start
+      // command needs CLI flags like `-t http -p <port>` appended).
+      args.push("--start-cmd", startCommand);
+    }
     const nodeVersion = detectNodeVersion(repoDir);
     if (nodeVersion) {
       // nixpacks does NOT read NIXPACKS_* config from the process environment — only from

apps/server/src/db/index.ts

@@ -36,6 +36,7 @@ CREATE TABLE IF NOT EXISTS installations (
 for (const ddl of [
   "ALTER TABLE installations ADD COLUMN basic_auth_username TEXT",
   "ALTER TABLE installations ADD COLUMN basic_auth_password_encrypted TEXT",
+  "ALTER TABLE installations ADD COLUMN start_command TEXT",
 ]) {
   try {
     db.exec(ddl);

apps/server/src/db/installations.ts

@@ -31,6 +31,7 @@ export interface Installation {
   bearerToken: string | null;
   basicAuthUsername: string | null;
   basicAuthPassword: string | null;
+  startCommand: string | null;
   createdAt: string;
   updatedAt: string;
 }
@@ -54,6 +55,7 @@ interface Row {
   env_json_encrypted: string | null;
   basic_auth_username: string | null;
   basic_auth_password_encrypted: string | null;
+  start_command: string | null;
   created_at: string;
   updated_at: string;
 }
@@ -78,6 +80,7 @@ function rowToInstallation(row: Row): Installation {
     bearerToken: row.bearer_token_encrypted ? decryptSecret(row.bearer_token_encrypted) : null,
     basicAuthUsername: row.basic_auth_username,
     basicAuthPassword: row.basic_auth_password_encrypted ? decryptSecret(row.basic_auth_password_encrypted) : null,
+    startCommand: row.start_command,
     createdAt: row.created_at,
     updatedAt: row.updated_at,
   };
@@ -140,6 +143,7 @@ export interface InstallationUpdate {
   bearerToken?: string | null;
   basicAuthUsername?: string | null;
   basicAuthPassword?: string | null;
+  startCommand?: string | null;
   gitRef?: string | null;
 }
 
@@ -162,6 +166,7 @@ export function updateInstallation(id: string, patch: InstallationUpdate): Insta
       patch.basicAuthUsername !== undefined ? patch.basicAuthUsername : current.basicAuthUsername,
     basicAuthPassword:
       patch.basicAuthPassword !== undefined ? patch.basicAuthPassword : current.basicAuthPassword,
+    startCommand: patch.startCommand !== undefined ? patch.startCommand : current.startCommand,
     gitRef: patch.gitRef !== undefined ? patch.gitRef : current.gitRef,
   };
 
@@ -179,6 +184,7 @@ export function updateInstallation(id: string, patch: InstallationUpdate): Insta
       bearer_token_encrypted = @bearerTokenEncrypted,
       basic_auth_username = @basicAuthUsername,
       basic_auth_password_encrypted = @basicAuthPasswordEncrypted,
+      start_command = @startCommand,
       git_ref = @gitRef,
       updated_at = @updatedAt
      WHERE id = @id`,
@@ -196,6 +202,7 @@ export function updateInstallation(id: string, patch: InstallationUpdate): Insta
     bearerTokenEncrypted: next.bearerToken ? encryptSecret(next.bearerToken) : null,
     basicAuthUsername: next.basicAuthUsername,
     basicAuthPasswordEncrypted: next.basicAuthPassword ? encryptSecret(next.basicAuthPassword) : null,
+    startCommand: next.startCommand,
     gitRef: next.gitRef,
     updatedAt: new Date().toISOString(),
   });

apps/server/src/service/orchestrator.ts

@@ -55,6 +55,7 @@ export function configureInstallation(
     internalPort?: number;
     basicAuthUsername?: string | null;
     basicAuthPassword?: string | null;
+    startCommand?: string | null;
   },
 ): Installation {
   return updateInstallation(id, patch);
@@ -68,7 +69,12 @@ export async function buildInstallation(id: string): Promise<Installation> {
   const imageTag = `mcpmgr/${installation.slug}:latest`;
   const previousImageId = installation.imageTag ? await getImageId(installation.imageTag) : undefined;
 
-  const result = await runNixpacksBuild(installation.slug, repoDir(installation.slug), imageTag);
+  const result = await runNixpacksBuild(
+    installation.slug,
+    repoDir(installation.slug),
+    imageTag,
+    installation.startCommand,
+  );
 
   if (!result.success) {
     return updateInstallation(id, {