diff --git a/CHANGELOG.md b/CHANGELOG.md
index 108861360ef..e2191180ed0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,7 @@ Docs: https://docs.openclaw.ai
 - Plugins: add `before_agent_start` model/provider overrides before resolution. (#18568) Thanks @natefikru.
 - Memory/Search: add FTS fallback plus query expansion for memory search. (#18304) Thanks @irchelper.
 - Agents/Models: support per-model `thinkingDefault` overrides in model config. (#18152) Thanks @wu-tian807.
+- Agents/Models: support Anthropic Sonnet 4.6 (`anthropic/claude-sonnet-4-6`) across aliases/defaults with forward-compat fallback when upstream catalogs still only expose Sonnet 4.5.
 - Agents: enable `llms.txt` discovery in default behavior. (#18158) Thanks @yolo-maxi.
 - Feishu: add Bitable create-app/create-field tools for automation workflows. (#17963) Thanks @gaowanqi08141999.
 - Cron/Gateway: separate per-job webhook delivery (`delivery.mode = "webhook"`) from announce delivery, enforce valid HTTP(S) webhook URLs, and keep a temporary legacy `notify + cron.webhook` fallback for stored jobs. (#17901) Thanks @advaitpaliwal.
diff --git a/docs/help/testing.md b/docs/help/testing.md
index a0ab38f7843..325ca16f3e9 100644
--- a/docs/help/testing.md
+++ b/docs/help/testing.md
@@ -200,7 +200,7 @@ OPENCLAW_LIVE_SETUP_TOKEN=1 OPENCLAW_LIVE_SETUP_TOKEN_PROFILE=anthropic:setup-to
   - `pnpm test:live` (or `OPENCLAW_LIVE_TEST=1` if invoking Vitest directly)
   - `OPENCLAW_LIVE_CLI_BACKEND=1`
 - Defaults:
-  - Model: `claude-cli/claude-sonnet-4-5`
+  - Model: `claude-cli/claude-sonnet-4-6`
   - Command: `claude`
   - Args: `["-p","--output-format","json","--dangerously-skip-permissions"]`
 - Overrides (optional):
@@ -219,7 +219,7 @@ Example:
 
 ```bash
 OPENCLAW_LIVE_CLI_BACKEND=1 \
-  OPENCLAW_LIVE_CLI_BACKEND_MODEL="claude-cli/claude-sonnet-4-5" \
+  OPENCLAW_LIVE_CLI_BACKEND_MODEL="claude-cli/claude-sonnet-4-6" \
   pnpm test:live src/gateway/gateway-cli-backend.live.test.ts
 ```
 
diff --git a/src/agents/anthropic.setup-token.live.test.ts b/src/agents/anthropic.setup-token.live.test.ts
index a8a7859c7f4..182a20e5c2a 100644
--- a/src/agents/anthropic.setup-token.live.test.ts
+++ b/src/agents/anthropic.setup-token.live.test.ts
@@ -1,8 +1,8 @@
+import { type Api, completeSimple, type Model } from "@mariozechner/pi-ai";
 import { randomUUID } from "node:crypto";
 import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
-import { type Api, completeSimple, type Model } from "@mariozechner/pi-ai";
 import { describe, expect, it } from "vitest";
 import {
   ANTHROPIC_SETUP_TOKEN_PREFIX,
@@ -142,6 +142,7 @@ function pickModel(models: Array<Model<Api>>, raw?: string): Model<Api> | null {
 
   const preferred = [
     "claude-opus-4-5",
+    "claude-sonnet-4-6",
     "claude-sonnet-4-5",
     "claude-sonnet-4-0",
     "claude-haiku-3-5",
diff --git a/src/agents/cli-backends.ts b/src/agents/cli-backends.ts
index 2f1db0f87a6..cf3cdb4bb18 100644
--- a/src/agents/cli-backends.ts
+++ b/src/agents/cli-backends.ts
@@ -20,9 +20,11 @@ const CLAUDE_MODEL_ALIASES: Record<string, string> = {
   "claude-opus-4-5": "opus",
   "claude-opus-4": "opus",
   sonnet: "sonnet",
+  "sonnet-4.6": "sonnet",
   "sonnet-4.5": "sonnet",
   "sonnet-4.1": "sonnet",
   "sonnet-4.0": "sonnet",
+  "claude-sonnet-4-6": "sonnet",
   "claude-sonnet-4-5": "sonnet",
   "claude-sonnet-4-1": "sonnet",
   "claude-sonnet-4-0": "sonnet",
diff --git a/src/agents/live-model-filter.ts b/src/agents/live-model-filter.ts
index 97d22da9742..dbaba0c7df1 100644
--- a/src/agents/live-model-filter.ts
+++ b/src/agents/live-model-filter.ts
@@ -5,6 +5,7 @@ export type ModelRef = {
 
 const ANTHROPIC_PREFIXES = [
   "claude-opus-4-6",
+  "claude-sonnet-4-6",
   "claude-opus-4-5",
   "claude-sonnet-4-5",
   "claude-haiku-4-5",
diff --git a/src/agents/model-forward-compat.ts b/src/agents/model-forward-compat.ts
index 9694c548d0f..dc566f9da5c 100644
--- a/src/agents/model-forward-compat.ts
+++ b/src/agents/model-forward-compat.ts
@@ -1,8 +1,8 @@
 import type { Api, Model } from "@mariozechner/pi-ai";
+import type { ModelRegistry } from "./pi-model-discovery.js";
 import { DEFAULT_CONTEXT_TOKENS } from "./defaults.js";
 import { normalizeModelCompat } from "./model-compat.js";
 import { normalizeProviderId } from "./model-selection.js";
-import type { ModelRegistry } from "./pi-model-discovery.js";
 
 const OPENAI_CODEX_GPT_53_MODEL_ID = "gpt-5.3-codex";
 const OPENAI_CODEX_TEMPLATE_MODEL_IDS = ["gpt-5.2-codex"] as const;
@@ -10,6 +10,9 @@ const OPENAI_CODEX_TEMPLATE_MODEL_IDS = ["gpt-5.2-codex"] as const;
 const ANTHROPIC_OPUS_46_MODEL_ID = "claude-opus-4-6";
 const ANTHROPIC_OPUS_46_DOT_MODEL_ID = "claude-opus-4.6";
 const ANTHROPIC_OPUS_TEMPLATE_MODEL_IDS = ["claude-opus-4-5", "claude-opus-4.5"] as const;
+const ANTHROPIC_SONNET_46_MODEL_ID = "claude-sonnet-4-6";
+const ANTHROPIC_SONNET_46_DOT_MODEL_ID = "claude-sonnet-4.6";
+const ANTHROPIC_SONNET_TEMPLATE_MODEL_IDS = ["claude-sonnet-4-5", "claude-sonnet-4.5"] as const;
 
 const ZAI_GLM5_MODEL_ID = "glm-5";
 const ZAI_GLM5_TEMPLATE_MODEL_IDS = ["glm-4.7"] as const;
@@ -139,6 +142,44 @@ function resolveAnthropicOpus46ForwardCompatModel(
   });
 }
 
+function resolveAnthropicSonnet46ForwardCompatModel(
+  provider: string,
+  modelId: string,
+  modelRegistry: ModelRegistry,
+): Model<Api> | undefined {
+  const normalizedProvider = normalizeProviderId(provider);
+  if (normalizedProvider !== "anthropic") {
+    return undefined;
+  }
+
+  const trimmedModelId = modelId.trim();
+  const lower = trimmedModelId.toLowerCase();
+  const isSonnet46 =
+    lower === ANTHROPIC_SONNET_46_MODEL_ID ||
+    lower === ANTHROPIC_SONNET_46_DOT_MODEL_ID ||
+    lower.startsWith(`${ANTHROPIC_SONNET_46_MODEL_ID}-`) ||
+    lower.startsWith(`${ANTHROPIC_SONNET_46_DOT_MODEL_ID}-`);
+  if (!isSonnet46) {
+    return undefined;
+  }
+
+  const templateIds: string[] = [];
+  if (lower.startsWith(ANTHROPIC_SONNET_46_MODEL_ID)) {
+    templateIds.push(lower.replace(ANTHROPIC_SONNET_46_MODEL_ID, "claude-sonnet-4-5"));
+  }
+  if (lower.startsWith(ANTHROPIC_SONNET_46_DOT_MODEL_ID)) {
+    templateIds.push(lower.replace(ANTHROPIC_SONNET_46_DOT_MODEL_ID, "claude-sonnet-4.5"));
+  }
+  templateIds.push(...ANTHROPIC_SONNET_TEMPLATE_MODEL_IDS);
+
+  return cloneFirstTemplateModel({
+    normalizedProvider,
+    trimmedModelId,
+    templateIds,
+    modelRegistry,
+  });
+}
+
 // Z.ai's GLM-5 may not be present in pi-ai's built-in model catalog yet.
 // When a user configures zai/glm-5 without a models.json entry, clone glm-4.7 as a forward-compat fallback.
 function resolveZaiGlm5ForwardCompatModel(
@@ -243,6 +284,7 @@ export function resolveForwardCompatModel(
   return (
     resolveOpenAICodexGpt53FallbackModel(provider, modelId, modelRegistry) ??
     resolveAnthropicOpus46ForwardCompatModel(provider, modelId, modelRegistry) ??
+    resolveAnthropicSonnet46ForwardCompatModel(provider, modelId, modelRegistry) ??
     resolveZaiGlm5ForwardCompatModel(provider, modelId, modelRegistry) ??
     resolveAntigravityOpus46ForwardCompatModel(provider, modelId, modelRegistry)
   );
diff --git a/src/agents/model-selection.e2e.test.ts b/src/agents/model-selection.e2e.test.ts
index 6638d5720b1..d04517d0166 100644
--- a/src/agents/model-selection.e2e.test.ts
+++ b/src/agents/model-selection.e2e.test.ts
@@ -45,6 +45,14 @@ describe("model-selection", () => {
         provider: "anthropic",
         model: "claude-opus-4-6",
       });
+      expect(parseModelRef("anthropic/sonnet-4.6", "openai")).toEqual({
+        provider: "anthropic",
+        model: "claude-sonnet-4-6",
+      });
+      expect(parseModelRef("sonnet-4.6", "anthropic")).toEqual({
+        provider: "anthropic",
+        model: "claude-sonnet-4-6",
+      });
     });
 
     it("should use default provider if none specified", () => {
diff --git a/src/agents/model-selection.ts b/src/agents/model-selection.ts
index 04a87ece072..4cba18fcc9a 100644
--- a/src/agents/model-selection.ts
+++ b/src/agents/model-selection.ts
@@ -1,7 +1,7 @@
 import type { OpenClawConfig } from "../config/config.js";
+import type { ModelCatalogEntry } from "./model-catalog.js";
 import { resolveAgentModelPrimary } from "./agent-scope.js";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "./defaults.js";
-import type { ModelCatalogEntry } from "./model-catalog.js";
 import { normalizeGoogleModelId } from "./models-config.providers.js";
 
 export type ModelRef = {
@@ -19,6 +19,7 @@ export type ModelAliasIndex = {
 const ANTHROPIC_MODEL_ALIASES: Record<string, string> = {
   "opus-4.6": "claude-opus-4-6",
   "opus-4.5": "claude-opus-4-5",
+  "sonnet-4.6": "claude-sonnet-4-6",
   "sonnet-4.5": "claude-sonnet-4-5",
 };
 const OPENAI_CODEX_OAUTH_MODEL_PREFIXES = ["gpt-5.3-codex"] as const;
diff --git a/src/agents/pi-embedded-runner/model.test.ts b/src/agents/pi-embedded-runner/model.test.ts
index 68fab01ad6e..1c3cebce8d0 100644
--- a/src/agents/pi-embedded-runner/model.test.ts
+++ b/src/agents/pi-embedded-runner/model.test.ts
@@ -217,6 +217,32 @@ describe("resolveModel", () => {
     });
   });
 
+  it("builds an anthropic forward-compat fallback for claude-sonnet-4-6", () => {
+    mockDiscoveredModel({
+      provider: "anthropic",
+      modelId: "claude-sonnet-4-5",
+      templateModel: buildForwardCompatTemplate({
+        id: "claude-sonnet-4-5",
+        name: "Claude Sonnet 4.5",
+        provider: "anthropic",
+        api: "anthropic-messages",
+        baseUrl: "https://api.anthropic.com",
+      }),
+    });
+
+    expectResolvedForwardCompatFallback({
+      provider: "anthropic",
+      id: "claude-sonnet-4-6",
+      expectedModel: {
+        provider: "anthropic",
+        id: "claude-sonnet-4-6",
+        api: "anthropic-messages",
+        baseUrl: "https://api.anthropic.com",
+        reasoning: true,
+      },
+    });
+  });
+
   it("builds an antigravity forward-compat fallback for claude-opus-4-6-thinking", () => {
     mockDiscoveredModel({
       provider: "google-antigravity",
diff --git a/src/commands/configure.gateway-auth.ts b/src/commands/configure.gateway-auth.ts
index fa37d876f0d..a5560cd63ac 100644
--- a/src/commands/configure.gateway-auth.ts
+++ b/src/commands/configure.gateway-auth.ts
@@ -1,7 +1,7 @@
-import { ensureAuthProfileStore } from "../agents/auth-profiles.js";
 import type { OpenClawConfig, GatewayAuthConfig } from "../config/config.js";
 import type { RuntimeEnv } from "../runtime.js";
 import type { WizardPrompter } from "../wizard/prompts.js";
+import { ensureAuthProfileStore } from "../agents/auth-profiles.js";
 import { promptAuthChoiceGrouped } from "./auth-choice-prompt.js";
 import { applyAuthChoice, resolvePreferredProviderForAuthChoice } from "./auth-choice.js";
 import {
@@ -30,6 +30,7 @@ function sanitizeTokenValue(value: string | undefined): string | undefined {
 
 const ANTHROPIC_OAUTH_MODEL_KEYS = [
   "anthropic/claude-opus-4-6",
+  "anthropic/claude-sonnet-4-6",
   "anthropic/claude-opus-4-5",
   "anthropic/claude-sonnet-4-5",
   "anthropic/claude-haiku-4-5",
diff --git a/src/config/defaults.ts b/src/config/defaults.ts
index cecc8d9e226..c8c1c841926 100644
--- a/src/config/defaults.ts
+++ b/src/config/defaults.ts
@@ -1,9 +1,9 @@
+import type { OpenClawConfig } from "./types.js";
+import type { ModelDefinitionConfig } from "./types.models.js";
 import { DEFAULT_CONTEXT_TOKENS } from "../agents/defaults.js";
 import { parseModelRef } from "../agents/model-selection.js";
 import { DEFAULT_AGENT_MAX_CONCURRENT, DEFAULT_SUBAGENT_MAX_CONCURRENT } from "./agent-limits.js";
 import { resolveTalkApiKey } from "./talk.js";
-import type { OpenClawConfig } from "./types.js";
-import type { ModelDefinitionConfig } from "./types.models.js";
 
 type WarnState = { warned: boolean };
 
@@ -14,7 +14,7 @@ type AnthropicAuthDefaultsMode = "api_key" | "oauth";
 const DEFAULT_MODEL_ALIASES: Readonly<Record<string, string>> = {
   // Anthropic (pi-ai catalog uses "latest" ids without date suffix)
   opus: "anthropic/claude-opus-4-6",
-  sonnet: "anthropic/claude-sonnet-4-5",
+  sonnet: "anthropic/claude-sonnet-4-6",
 
   // OpenAI
   gpt: "openai/gpt-5.2",
diff --git a/src/gateway/gateway-cli-backend.live.test.ts b/src/gateway/gateway-cli-backend.live.test.ts
index f8a8439ce72..4724ee29fd8 100644
--- a/src/gateway/gateway-cli-backend.live.test.ts
+++ b/src/gateway/gateway-cli-backend.live.test.ts
@@ -18,7 +18,7 @@ const CLI_IMAGE = isTruthyEnvValue(process.env.OPENCLAW_LIVE_CLI_BACKEND_IMAGE_P
 const CLI_RESUME = isTruthyEnvValue(process.env.OPENCLAW_LIVE_CLI_BACKEND_RESUME_PROBE);
 const describeLive = LIVE && CLI_LIVE ? describe : describe.skip;
 
-const DEFAULT_MODEL = "claude-cli/claude-sonnet-4-5";
+const DEFAULT_MODEL = "claude-cli/claude-sonnet-4-6";
 const DEFAULT_CLAUDE_ARGS = ["-p", "--output-format", "json", "--dangerously-skip-permissions"];
 const DEFAULT_CODEX_ARGS = [
   "exec",