diff --git a/open-sse/config/providerRegistry.ts b/open-sse/config/providerRegistry.ts
index ede6e0cdff..d797e21087 100644
--- a/open-sse/config/providerRegistry.ts
+++ b/open-sse/config/providerRegistry.ts
@@ -1199,9 +1199,9 @@ export const REGISTRY: Record<string, RegistryEntry> = {
     authType: "apikey",
     authHeader: "bearer",
     models: [
-      { id: "gpt-oss-120b", name: "GPT OSS 120B", toolCalling: false },
-      { id: "openai/gpt-oss-120b", name: "GPT OSS 120B (OpenAI Prefix)", toolCalling: false },
-      { id: "openai/gpt-oss-20b", name: "GPT OSS 20B", toolCalling: false },
+      { id: "gpt-oss-120b", name: "GPT OSS 120B" },
+      { id: "openai/gpt-oss-120b", name: "GPT OSS 120B (OpenAI Prefix)" },
+      { id: "openai/gpt-oss-20b", name: "GPT OSS 20B" },
       { id: "meta/llama-3.3-70b-instruct", name: "Llama 3.3 70B" },
       { id: "nvidia/llama-3.3-70b-instruct", name: "Llama 3.3 70B (NVIDIA Prefix)" },
       { id: "meta/llama-4-maverick-17b-128e-instruct", name: "Llama 4 Maverick" },
diff --git a/src/lib/modelCapabilities.ts b/src/lib/modelCapabilities.ts
index 7ee0354550..45f1aa7c3d 100644
--- a/src/lib/modelCapabilities.ts
+++ b/src/lib/modelCapabilities.ts
@@ -6,7 +6,7 @@ import { parseModel, resolveCanonicalProviderModel } from "@omniroute/open-sse/s
 import { MODEL_SPECS, getModelSpec, type ModelSpec } from "@/shared/constants/modelSpecs";
 import { getSyncedCapability } from "@/lib/modelsDevSync";
 
-const TOOL_CALLING_UNSUPPORTED_PATTERNS = ["gpt-oss-120b", "deepseek-reasoner"];
+const TOOL_CALLING_UNSUPPORTED_PATTERNS: string[] = [];
 const REASONING_UNSUPPORTED_PATTERNS = [
   "antigravity/claude-sonnet-4-6",
   "antigravity/claude-sonnet-4-5",
diff --git a/tests/unit/model-capabilities-registry.test.ts b/tests/unit/model-capabilities-registry.test.ts
index d862cc54bc..1dbc1bd240 100644
--- a/tests/unit/model-capabilities-registry.test.ts
+++ b/tests/unit/model-capabilities-registry.test.ts
@@ -103,3 +103,20 @@ test("canonical model capability resolver merges models.dev data and keeps stati
     32768
   );
 });
+
+test("GPT OSS and DeepSeek Reasoner models support tool calling", () => {
+  // GPT OSS models should not be blocked by the heuristic
+  assert.equal(modelCapabilities.supportsToolCalling("nvidia/gpt-oss-120b"), true);
+  assert.equal(modelCapabilities.supportsToolCalling("gpt-oss-120b"), true);
+  assert.equal(modelCapabilities.supportsToolCalling("openai/gpt-oss-20b"), true);
+
+  // DeepSeek Reasoner supports tool calling
+  assert.equal(modelCapabilities.supportsToolCalling("deepseek-reasoner"), true);
+  assert.equal(modelCapabilities.supportsToolCalling("deepseek/deepseek-r1"), true);
+
+  // Full capability resolution
+  const gptOss = modelCapabilities.getResolvedModelCapabilities("nvidia/gpt-oss-120b");
+  assert.equal(gptOss.toolCalling, true);
+  const deepseek = modelCapabilities.getResolvedModelCapabilities("deepseek/deepseek-reasoner");
+  assert.equal(deepseek.toolCalling, true);
+});
diff --git a/tests/unit/services-branch-hardening.test.ts b/tests/unit/services-branch-hardening.test.ts
index 16467867d4..6adef33e1f 100644
--- a/tests/unit/services-branch-hardening.test.ts
+++ b/tests/unit/services-branch-hardening.test.ts
@@ -79,8 +79,8 @@ test("model capability helpers cover denylist, empty input and default-safe path
   assert.equal(modelCapabilities.supportsReasoning("missing-provider/tool"), true);
 
   assert.equal(modelCapabilities.supportsToolCalling(""), false);
-  assert.equal(modelCapabilities.supportsToolCalling("openai/gpt-oss-120b"), false);
-  assert.equal(modelCapabilities.supportsToolCalling("deepseek-reasoner"), false);
+  assert.equal(modelCapabilities.supportsToolCalling("openai/gpt-oss-120b"), true);
+  assert.equal(modelCapabilities.supportsToolCalling("deepseek-reasoner"), true);
   assert.equal(
     modelCapabilities.supportsToolCalling("openai/nonexistent-default-safe-model"),
     true