diff --git a/CHANGELOG.md b/CHANGELOG.md
index dfb50ac6c64..62a533849d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Models/openai-completions streaming compatibility: force `compat.supportsUsageInStreaming=false` for non-native OpenAI-compatible endpoints during model normalization, preventing usage-only stream chunks from triggering `choices[0]` parser crashes in provider streams. (#8714) Thanks @nonanon1.
 - TUI/token copy-safety rendering: treat long credential-like mixed alphanumeric tokens (including quoted forms) as copy-sensitive in render sanitization so formatter hard-wrap guards no longer inject visible spaces into auth-style values before display. (#26710) Thanks @jasonthane.
 - WhatsApp/self-chat response prefix fallback: stop forcing `"[openclaw]"` as the implicit outbound response prefix when no identity name or response prefix is configured, so blank/default prefix settings no longer inject branding text unexpectedly in self-chat flows. (#27962) Thanks @ecanmor.
 - Memory/QMD search result decoding: accept `qmd search` hits that only include `file` URIs (for example `qmd://collection/path.md`) without `docid`, resolve them through managed collection roots, and keep multi-collection results keyed by file fallback so valid QMD hits no longer collapse to empty `memory_search` output. (#28181) Thanks @0x76696265.
diff --git a/src/agents/model-compat.test.ts b/src/agents/model-compat.test.ts
index 2fd5df0883c..24361c0a534 100644
--- a/src/agents/model-compat.test.ts
+++ b/src/agents/model-compat.test.ts
@@ -23,6 +23,11 @@ function supportsDeveloperRole(model: Model<Api>): boolean | undefined {
   return (model.compat as { supportsDeveloperRole?: boolean } | undefined)?.supportsDeveloperRole;
 }
 
+function supportsUsageInStreaming(model: Model<Api>): boolean | undefined {
+  return (model.compat as { supportsUsageInStreaming?: boolean } | undefined)
+    ?.supportsUsageInStreaming;
+}
+
 function createTemplateModel(provider: string, id: string): Model<Api> {
   return {
     id,
@@ -82,6 +87,13 @@ function expectSupportsDeveloperRoleForcedOff(overrides?: Partial<Model<Api>>):
   expect(supportsDeveloperRole(normalized)).toBe(false);
 }
 
+function expectSupportsUsageInStreamingForcedOff(overrides?: Partial<Model<Api>>): void {
+  const model = { ...baseModel(), ...overrides };
+  delete (model as { compat?: unknown }).compat;
+  const normalized = normalizeModelCompat(model as Model<Api>);
+  expect(supportsUsageInStreaming(normalized)).toBe(false);
+}
+
 function expectResolvedForwardCompat(
   model: Model<Api> | undefined,
   expected: { provider: string; id: string },
@@ -207,6 +219,13 @@ describe("normalizeModelCompat", () => {
     });
   });
 
+  it("forces supportsUsageInStreaming off for generic custom openai-completions provider", () => {
+    expectSupportsUsageInStreamingForcedOff({
+      provider: "custom-cpa",
+      baseUrl: "https://cpa.example.com/v1",
+    });
+  });
+
   it("forces supportsDeveloperRole off for Qwen proxy via openai-completions", () => {
     expectSupportsDeveloperRoleForcedOff({
       provider: "qwen-proxy",
@@ -243,6 +262,17 @@ describe("normalizeModelCompat", () => {
     expect(supportsDeveloperRole(normalized)).toBe(false);
   });
 
+  it("overrides explicit supportsUsageInStreaming true on non-native endpoints", () => {
+    const model = {
+      ...baseModel(),
+      provider: "custom-cpa",
+      baseUrl: "https://proxy.example.com/v1",
+      compat: { supportsUsageInStreaming: true },
+    };
+    const normalized = normalizeModelCompat(model);
+    expect(supportsUsageInStreaming(normalized)).toBe(false);
+  });
+
   it("does not mutate caller model when forcing supportsDeveloperRole off", () => {
     const model = {
       ...baseModel(),
@@ -253,14 +283,17 @@ describe("normalizeModelCompat", () => {
     const normalized = normalizeModelCompat(model);
     expect(normalized).not.toBe(model);
     expect(supportsDeveloperRole(model)).toBeUndefined();
+    expect(supportsUsageInStreaming(model)).toBeUndefined();
     expect(supportsDeveloperRole(normalized)).toBe(false);
+    expect(supportsUsageInStreaming(normalized)).toBe(false);
   });
 
   it("does not override explicit compat false", () => {
     const model = baseModel();
-    model.compat = { supportsDeveloperRole: false };
+    model.compat = { supportsDeveloperRole: false, supportsUsageInStreaming: false };
     const normalized = normalizeModelCompat(model);
     expect(supportsDeveloperRole(normalized)).toBe(false);
+    expect(supportsUsageInStreaming(normalized)).toBe(false);
   });
 });
 
diff --git a/src/agents/model-compat.ts b/src/agents/model-compat.ts
index 48990f10bfd..7bad084fe57 100644
--- a/src/agents/model-compat.ts
+++ b/src/agents/model-compat.ts
@@ -52,28 +52,28 @@ export function normalizeModelCompat(model: Model<Api>): Model<Api> {
     return model;
   }
 
-  // The `developer` message role is an OpenAI-native convention. All other
-  // openai-completions backends (proxies, Qwen, GLM, DeepSeek, Kimi, etc.)
-  // only recognise `system`. Force supportsDeveloperRole=false for any model
-  // whose baseUrl is not a known native OpenAI endpoint, unless the caller
-  // has already pinned the value explicitly.
+  // The `developer` role and stream usage chunks are OpenAI-native behaviors.
+  // Many OpenAI-compatible backends reject `developer` and/or emit usage-only
+  // chunks that break strict parsers expecting choices[0]. For non-native
+  // openai-completions endpoints, force both compat flags off.
   const compat = model.compat ?? undefined;
-  if (compat?.supportsDeveloperRole === false) {
-    return model;
-  }
   // When baseUrl is empty the pi-ai library defaults to api.openai.com, so
-  // leave compat unchanged and let the existing default behaviour apply.
-  // Note: an explicit supportsDeveloperRole: true is intentionally overridden
-  // here for non-native endpoints — those backends would return a 400 if we
-  // sent `developer`, so safety takes precedence over the caller's hint.
+  // leave compat unchanged and let default native behavior apply.
+  // Note: explicit true values are intentionally overridden for non-native
+  // endpoints for safety.
   const needsForce = baseUrl ? !isOpenAINativeEndpoint(baseUrl) : false;
   if (!needsForce) {
     return model;
   }
+  if (compat?.supportsDeveloperRole === false && compat?.supportsUsageInStreaming === false) {
+    return model;
+  }
 
   // Return a new object — do not mutate the caller's model reference.
   return {
     ...model,
-    compat: compat ? { ...compat, supportsDeveloperRole: false } : { supportsDeveloperRole: false },
+    compat: compat
+      ? { ...compat, supportsDeveloperRole: false, supportsUsageInStreaming: false }
+      : { supportsDeveloperRole: false, supportsUsageInStreaming: false },
   } as typeof model;
 }