fix(cline): force upstream streaming for Cline/ClinePass (streaming-only API)

Cline's API (api.cline.bot) only implements streaming (streamText). A
non-streaming request returns HTTP 500 "generateText is not implemented" (Claude
models) or HTTP 502 "empty response" (others). Live-verified on the VPS:
stream:true → works (STREAM_OK), stream:false → fails. This is why testing a Cline
model in the dashboard (the test button sends stream:false) failed.

Fix (reuses the existing isClaudeCodeCompatible mechanism, no new handler):
- Flag `cline` and `clinepass` registry entries with `forceStream: true`.
- In chatCore, OR `providerRequiresStreaming` into `upstreamStream` (line 1591)
  so the upstream request always streams for these providers, while the client's
  original `stream` intent still drives the response format. The existing
  non-streaming branch (parseNonStreamingResponseBody) already accumulates the
  upstream SSE and converts it back to JSON for stream:false clients — the same
  path Claude-Code-compatible providers already use.

Tests (Rule #18): tests/unit/cline-force-stream.test.ts pins the registry flags +
resolveStreamFlag forcing behavior. Live VPS before/after recorded on the PR.

open-sse/config/providers/registry/cline/index.ts

@@ -5,6 +5,11 @@ export const clineProvider: RegistryEntry = {
   alias: "cl",
   format: "openai",
   executor: "openai",
+  // Cline's API only implements streaming (streamText). A non-streaming request
+  // returns "generateText is not implemented" / an empty body, so force upstream
+  // streaming and let chatCore convert the SSE back to JSON for stream:false
+  // clients (e.g. the model-test button, non-streaming API callers).
+  forceStream: true,
   baseUrl: "https://api.cline.bot/api/v1/chat/completions",
   authType: "oauth",
   authHeader: "Authorization",

open-sse/config/providers/registry/clinepass/index.ts

@@ -9,6 +9,11 @@ export const clinepassProvider: RegistryEntry = {
   alias: "clinepass",
   format: "openai",
   executor: "default",
+  // ClinePass shares Cline's streaming-only API — a non-streaming request returns
+  // "generateText is not implemented" / an empty body. Force upstream streaming;
+  // chatCore accumulates the SSE and converts it back to JSON for stream:false
+  // clients. (Same as the sibling `cline` provider.)
+  forceStream: true,
   baseUrl: "https://api.cline.bot/api/v1/chat/completions",
   authType: "apikey",
   authHeader: "bearer",

open-sse/handlers/chatCore.ts

@@ -1588,7 +1588,13 @@ export async function handleChatCore({
     headers: clientRawRequest?.headers,
     userAgent,
   });
-  const upstreamStream = stream || isClaudeCodeCompatible;
+  // `forceStream` providers (e.g. Cline / ClinePass) only implement upstream
+  // streaming — a non-streaming request returns "generateText is not implemented"
+  // / an empty body. Force the upstream request to stream even when the client
+  // wants JSON; the non-streaming branch below accumulates the SSE and converts
+  // it back to JSON (same mechanism already used for Claude-Code-compatible
+  // providers via isClaudeCodeCompatible).
+  const upstreamStream = stream || isClaudeCodeCompatible || providerRequiresStreaming;
   let ccSessionId: string | null = null;
   const stripTypes = getStripTypesForProviderModel(provider || "", model || "");
 

tests/unit/cline-force-stream.test.ts

@@ -0,0 +1,37 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { REGISTRY } from "@omniroute/open-sse/config/providers/index.ts";
+import { resolveStreamFlag } from "@omniroute/open-sse/utils/aiSdkCompat.ts";
+
+// Cline / ClinePass only implement upstream streaming — a non-streaming request
+// returns "generateText is not implemented" / an empty body. They must carry
+// `forceStream: true` so chatCore forces upstream streaming (upstreamStream) even
+// when the client wants JSON, then converts the SSE back to JSON. Regression guard
+// for the "cline model test → generateText is not implemented / empty response"
+// bug (live-verified on the VPS: stream:true works, stream:false failed).
+
+test("cline provider is flagged forceStream (streaming-only upstream)", () => {
+  assert.equal(REGISTRY.cline?.forceStream, true);
+});
+
+test("clinepass provider is flagged forceStream (streaming-only upstream)", () => {
+  assert.equal(REGISTRY.clinepass?.forceStream, true);
+});
+
+test("resolveStreamFlag forces streaming for a forceStream provider even when the client sent stream:false", () => {
+  // providerRequiresStreaming derives from REGISTRY[provider].forceStream === true
+  const providerRequiresStreaming = REGISTRY.cline?.forceStream === true;
+  assert.equal(
+    resolveStreamFlag(false, "application/json", "openai", { providerRequiresStreaming }),
+    true
+  );
+});
+
+test("resolveStreamFlag still honors stream:false for a normal (non-forceStream) provider", () => {
+  const providerRequiresStreaming = REGISTRY.openai?.forceStream === true; // false
+  assert.equal(
+    resolveStreamFlag(false, "application/json", "openai", { providerRequiresStreaming }),
+    false
+  );
+});