diff --git a/changelog.d/fixes/6142-6142-devin-unified-api.md b/changelog.d/fixes/6142-6142-devin-unified-api.md
new file mode 100644
index 0000000000..bda88bd4c8
--- /dev/null
+++ b/changelog.d/fixes/6142-6142-devin-unified-api.md
@@ -0,0 +1 @@
+- fix(providers): wire the Devin cloud-agent provider into the generic provider-page validator and static model catalog, matching the existing `jules` cloud-agent pattern (#6142)
diff --git a/src/lib/providers/staticModels.ts b/src/lib/providers/staticModels.ts
index 271590670b..88bb6d85d8 100644
--- a/src/lib/providers/staticModels.ts
+++ b/src/lib/providers/staticModels.ts
@@ -79,6 +79,12 @@ const STATIC_MODEL_PROVIDERS: Record<string, () => Array<{ id: string; name: str
     // Google Labs async coding agent — single async session, no model selection.
     { id: "jules", name: "Jules (Google Labs coding agent)" },
   ],
+  devin: () => [
+    // Cognition's Devin cloud-agent sessions don't expose per-request model
+    // selection like devin-cli's ACP models do — single non-selectable placeholder
+    // so the "Available Models" UI shows something instead of a hard failure (#6142).
+    { id: "devin", name: "Devin (Cognition cloud agent)" },
+  ],
   "linkup-search": () => [
     // Linkup web search — the "model" is the search depth (docs.linkup.so #5571).
     { id: "standard", name: "Standard (single-iteration agentic search)" },
diff --git a/src/lib/providers/validation.ts b/src/lib/providers/validation.ts
index f97d8eeb13..08eccca4d6 100644
--- a/src/lib/providers/validation.ts
+++ b/src/lib/providers/validation.ts
@@ -45,6 +45,7 @@ import {
   validateCopilotWebProvider,
   validateT3WebProvider,
   validateJulesProvider,
+  validateDevinCloudAgentProvider,
   validateInnerAiProvider,
 } from "./validation/webProvidersB";
 import {
@@ -390,6 +391,10 @@ export async function validateProviderApiKey({ provider, apiKey, providerSpecifi
       }
     },
     jules: validateJulesProvider,
+    // "devin" is the Cognition cloud-agent provider (distinct from the "devin-cli"
+    // LLM/ACP provider, which is already registered in providerRegistry). Wired here
+    // for parity with the "jules" cloud-agent entry above — see #6142.
+    devin: validateDevinCloudAgentProvider,
     // auggie is a fully local, credential-less CLI passthrough — there is no API
     // key to check upstream. The only meaningful validation is confirming the
     // `auggie` binary is installed and runnable on this machine.
diff --git a/src/lib/providers/validation/webProvidersB.ts b/src/lib/providers/validation/webProvidersB.ts
index e28e135c4c..9a1afb128b 100644
--- a/src/lib/providers/validation/webProvidersB.ts
+++ b/src/lib/providers/validation/webProvidersB.ts
@@ -1,6 +1,7 @@
 // Web-cookie provider key validators (part B): muse-spark-web, adapta-web, claude-web, gemini-web,
-// copilot-web, t3-web, jules, inner-ai. Extracted from validation.ts (god-file decomposition) —
-// top-level functions with no dispatcher-state captures; behavior is byte-identical to the inline defs.
+// copilot-web, t3-web, jules, devin (cloud-agent), inner-ai. Extracted from validation.ts (god-file
+// decomposition) — top-level functions with no dispatcher-state captures; behavior is byte-identical
+// to the inline defs.
 import { applyCustomUserAgent } from "./headers";
 import { toValidationErrorResult, validationRead, validationWrite } from "./transport";
 import { normalizeSessionCookieHeader } from "@/lib/providers/webCookieAuth";
@@ -453,6 +454,38 @@ export async function validateJulesProvider({ apiKey }: { apiKey: string }) {
   }
 }
 
+/**
+ * Devin cloud-agent (Cognition) — GET /v1/sessions with Bearer auth
+ * (see docs.devin.ai/api-reference/sessions/list-sessions). Distinct from the
+ * "devin-cli" LLM provider (ACP), which is already wired via providerRegistry.
+ */
+export async function validateDevinCloudAgentProvider({ apiKey }: { apiKey: string }) {
+  try {
+    const response = await validationWrite("https://api.devin.ai/v1/sessions?limit=1", {
+      method: "GET",
+      headers: {
+        Authorization: `Bearer ${apiKey}`,
+      },
+    });
+
+    if (response.status === 401 || response.status === 403) {
+      return { valid: false, error: "Invalid API key" };
+    }
+
+    if (response.ok) {
+      return { valid: true, error: null };
+    }
+
+    const errorText = await response.text().catch(() => "");
+    return {
+      valid: false,
+      error: errorText.trim() || `Devin API returned ${response.status}`,
+    };
+  } catch (error: unknown) {
+    return toValidationErrorResult(error);
+  }
+}
+
 export async function validateInnerAiProvider({ apiKey, providerSpecificData = {} }: any) {
   try {
     const raw = typeof apiKey === "string" ? apiKey.trim() : "";
diff --git a/tests/unit/devin-cloud-agent-validator-6142.test.ts b/tests/unit/devin-cloud-agent-validator-6142.test.ts
new file mode 100644
index 0000000000..39463beadb
--- /dev/null
+++ b/tests/unit/devin-cloud-agent-validator-6142.test.ts
@@ -0,0 +1,71 @@
+// #6142 — devin cloud-agent provider validator + static model catalog wiring.
+// Regression guard for the "not supported" fallback devin used to always hit on the
+// generic Providers config page (parity with the existing jules cloud-agent wiring).
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { validateProviderApiKey } from "../../src/lib/providers/validation.ts";
+import { validateDevinCloudAgentProvider } from "../../src/lib/providers/validation/webProvidersB.ts";
+import { getStaticModelsForProvider } from "../../src/lib/providers/staticModels.ts";
+
+test("#6142: devin cloud-agent validator is wired into the SPECIALTY_VALIDATORS dispatcher", async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async () =>
+    new Response("{}", { status: 401 })) as unknown as typeof fetch;
+  try {
+    const result = await validateProviderApiKey({
+      provider: "devin",
+      apiKey: "cog_bad_key",
+    });
+    assert.equal(result.valid, false);
+    assert.equal(result.error, "Invalid API key");
+    assert.notEqual(result.unsupported, true);
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("#6142: validateDevinCloudAgentProvider maps 401 to Invalid API key", async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async () =>
+    new Response("{}", { status: 401 })) as unknown as typeof fetch;
+  try {
+    const result = await validateDevinCloudAgentProvider({ apiKey: "bad-key" });
+    assert.equal(result.valid, false);
+    assert.equal(result.error, "Invalid API key");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("#6142: validateDevinCloudAgentProvider maps 403 to Invalid API key", async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async () =>
+    new Response("{}", { status: 403 })) as unknown as typeof fetch;
+  try {
+    const result = await validateDevinCloudAgentProvider({ apiKey: "bad-key" });
+    assert.equal(result.valid, false);
+    assert.equal(result.error, "Invalid API key");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("#6142: validateDevinCloudAgentProvider accepts a 2xx probe as valid", async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async () =>
+    new Response(JSON.stringify({ sessions: [] }), { status: 200 })) as unknown as typeof fetch;
+  try {
+    const result = await validateDevinCloudAgentProvider({ apiKey: "cog_good_key" });
+    assert.equal(result.valid, true);
+    assert.equal(result.error, null);
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("#6142: devin exposes a static model catalog for the 'Available Models' UI (parity with jules)", () => {
+  const models = getStaticModelsForProvider("devin");
+  assert.ok(Array.isArray(models) && models.length > 0);
+  assert.equal(models[0].id, "devin");
+});
diff --git a/tests/unit/repro-6142-devin-cloud-agent-unwired.test.ts b/tests/unit/repro-6142-devin-cloud-agent-unwired.test.ts
new file mode 100644
index 0000000000..015e7e1300
--- /dev/null
+++ b/tests/unit/repro-6142-devin-cloud-agent-unwired.test.ts
@@ -0,0 +1,27 @@
+// tests/unit/repro-6142-devin-cloud-agent-unwired.test.ts
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { validateProviderApiKey } from "../../src/lib/providers/validation";
+import { getStaticModelsForProvider } from "../../src/lib/providers/staticModels";
+
+test("#6142 (fixed): saving a Devin cloud-agent API key should not be 'unsupported' by the generic provider flow (parity with jules)", async () => {
+  const result = await validateProviderApiKey({
+    provider: "devin",
+    apiKey: "cog_fake_service_user_token_for_repro",
+  });
+  assert.notEqual(
+    result.error,
+    "Provider validation not supported",
+    "devin should have a specialty validator wired (like jules), not fall through to 'not supported'"
+  );
+  assert.notEqual(result.unsupported, true);
+});
+
+test("#6142 (fixed): the 'Available Models' UI should have a usable static catalog for devin (parity with jules)", () => {
+  const devinStaticModels = getStaticModelsForProvider("devin");
+  assert.ok(
+    Array.isArray(devinStaticModels) && devinStaticModels.length > 0,
+    "devin should expose a static model catalog like jules does"
+  );
+});
diff --git a/tests/unit/validation-web-providers-split.test.ts b/tests/unit/validation-web-providers-split.test.ts
index 8b947604e7..0b321c69ed 100644
--- a/tests/unit/validation-web-providers-split.test.ts
+++ b/tests/unit/validation-web-providers-split.test.ts
@@ -25,7 +25,7 @@ test("webProvidersA exposes its six validators (deepseek/qwen/grok/chatgpt/perpl
   }
 });
 
-test("webProvidersB exposes its eight validators (muse-spark/adapta/claude/gemini/copilot/t3/jules/inner-ai)", () => {
+test("webProvidersB exposes its nine validators (muse-spark/adapta/claude/gemini/copilot/t3/jules/devin/inner-ai)", () => {
   for (const name of [
     "validateMuseSparkWebProvider",
     "validateAdaptaWebProvider",
@@ -34,6 +34,7 @@ test("webProvidersB exposes its eight validators (muse-spark/adapta/claude/gemin
     "validateCopilotWebProvider",
     "validateT3WebProvider",
     "validateJulesProvider",
+    "validateDevinCloudAgentProvider",
     "validateInnerAiProvider",
   ]) {
     assert.equal(typeof (B as Record<string, unknown>)[name], "function", `B missing ${name}`);