diff --git a/docker/daytona-runner/Dockerfile b/docker/daytona-runner/Dockerfile
index 5a1da31b1f..851d513265 100644
--- a/docker/daytona-runner/Dockerfile
+++ b/docker/daytona-runner/Dockerfile
@@ -140,7 +140,7 @@ RUN /bin/sh -lc 'set -eu; \
       command -v "$command_name" >/dev/null || { echo "FATAL: $command_name not on PATH for daytona user" >&2; exit 1; }; \
     done; \
     test "$(codex --version)" = "codex-cli 0.156.0"; \
-    test "$(claude --version)" = "2.1.280 (Claude Code)"; \
+    test "$(claude --version)" = "2.1.286 (Claude Code)"; \
     test "$(opencode --version)" = "1.18.32"; \
     test "$(acpx --version)" = "0.13.1"; \
     test "$(claude-agent-acp --version)" = "0.73.0"; \
diff --git a/docker/daytona-runner/README.md b/docker/daytona-runner/README.md
index cd54962638..950553197f 100644
--- a/docker/daytona-runner/README.md
+++ b/docker/daytona-runner/README.md
@@ -14,12 +14,12 @@ image that this Dockerfile can extend directly.
 
 ## Harness versions
 
-The September 22, 2026 refresh pins Codex 0.156.0, Claude Agent SDK
-0.3.280 (Claude Code 2.1.280), and OpenCode 1.18.32 in the shared provider
+The October 1, 2026 refresh pins Codex 0.156.0, Claude Agent SDK
+0.3.286 (Claude Code 2.1.286), and OpenCode 1.18.32 in the shared provider
 pack. Claude Code 2.1.280 is the minimum for
-[Opus 5.5](https://code.claude.com/docs/en/model-config); it also supports
-Fable 5.1. Codex uses the current
-[GPT-6 Sol and Luna model IDs](https://learn.chatgpt.com/docs/models).
+[Opus 5.5](https://code.claude.com/docs/en/model-config) and 2.1.284 is the
+minimum for Sonnet 5.5; the pinned runtime also supports Fable 5.1. Codex uses
+the current [GPT-6 Sol and Luna model IDs](https://learn.chatgpt.com/docs/models).
 Grok CLI 1.0.41 supports the current
 [Grok 4.7](https://docs.x.ai/developers/grok-4-7) model family.
 
diff --git a/package.json b/package.json
index 29223ed74e..a7fe131e30 100644
--- a/package.json
+++ b/package.json
@@ -122,7 +122,7 @@
     },
     "overrides": {
       "@agentclientprotocol/codex-acp@1.6.2>@openai/codex": "0.156.0",
-      "@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk": "0.3.280",
+      "@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk": "0.3.286",
       "rollup": ">=4.59.0",
       "react": "^19.2.8",
       "react-dom": "^19.2.8",
diff --git a/packages/adapters/claude-local/src/index.test.ts b/packages/adapters/claude-local/src/index.test.ts
index ce8bdf5a36..ff5342c028 100644
--- a/packages/adapters/claude-local/src/index.test.ts
+++ b/packages/adapters/claude-local/src/index.test.ts
@@ -8,10 +8,16 @@ describe("Claude model defaults", () => {
     expect(claudeLocalReasoningEffortsForModel(model)).toEqual(["low", "medium", "high", "xhigh", "max"]);
   });
 
+  it.each(["claude-sonnet-5-5", "claude-sonnet-5-5[1m]"])("requires CLI 2.1.284 and offers all efforts for %s", (model) => {
+    expect(minimumClaudeCliVersionForModel(model)).toBe("2.1.284");
+    expect(claudeLocalReasoningEffortsForModel(model)).toEqual(["low", "medium", "high", "xhigh", "max"]);
+  });
+
   it("keeps model-specific Claude reasoning limits", () => {
     expect(claudeLocalReasoningEffortsForModel("claude-fable-5-1")).toContain("xhigh");
     expect(claudeLocalReasoningEffortsForModel("claude-sonnet-5")).toContain("max");
     expect(claudeLocalReasoningEffortsForModel("claude-sonnet-4-6")).toEqual(["low", "medium", "high", "max"]);
+    expect(claudeLocalReasoningEffortsForModel("claude-sonnet-4-5")).toEqual(["low", "medium", "high"]);
     expect(claudeLocalReasoningEffortsForModel("claude-haiku-4-5")).toEqual([]);
     expect(claudeLocalReasoningEffortsForModel("custom-model")).toEqual(["low", "medium", "high"]);
   });
diff --git a/packages/adapters/claude-local/src/index.ts b/packages/adapters/claude-local/src/index.ts
index f5a71e4ea2..9268c47f95 100644
--- a/packages/adapters/claude-local/src/index.ts
+++ b/packages/adapters/claude-local/src/index.ts
@@ -26,7 +26,7 @@ export const type = "claude_local";
 export function claudeLocalReasoningEffortsForModel(model: string): readonly string[] {
   const id = model.trim().replace(/\[1m\]$/, "").replace(/^(?:(?:us|eu|apac|global)\.)?anthropic\./, "");
   if (/^claude-haiku-/.test(id)) return [];
-  if (/^claude-(?:opus-5(?:-5)?|opus-4-[78]|sonnet-5|fable-5(?:-1)?)$/.test(id)) {
+  if (/^claude-(?:opus-5(?:-5)?|opus-4-[78]|sonnet-5(?:-5)?|fable-5(?:-1)?)$/.test(id)) {
     return ["low", "medium", "high", "xhigh", "max"];
   }
   if (/^claude-(?:opus|sonnet)-4-6(?:-v1)?$/.test(id)) return ["low", "medium", "high", "max"];
@@ -43,13 +43,14 @@ export const models = [
   { id: "claude-fable-5-1", label: "Claude Fable 5.1" },
   { id: "claude-mythos-5", label: "Claude Mythos 5" },
   { id: "claude-opus-5-5", label: "Claude Opus 5.5" },
-  { id: "claude-sonnet-5", label: "Claude Sonnet 5" },
+  { id: "claude-sonnet-5-5", label: "Claude Sonnet 5.5" },
   { id: "claude-haiku-4-5", label: "Claude Haiku 4.5" },
   { id: "claude-fable-5", label: "Claude Fable 5" },
   { id: "claude-opus-5", label: "Claude Opus 5" },
   { id: "claude-opus-4-8", label: "Claude Opus 4.8" },
   { id: "claude-opus-4-7", label: "Claude Opus 4.7" },
   { id: "claude-opus-4-6", label: "Claude Opus 4.6" },
+  { id: "claude-sonnet-5", label: "Claude Sonnet 5" },
   { id: "claude-sonnet-4-6", label: "Claude Sonnet 4.6" },
   { id: "claude-sonnet-4-5", label: "Claude Sonnet 4.5" },
 ];
@@ -63,7 +64,7 @@ Core fields:
 - cwd (string, optional): default absolute working directory fallback for the agent process (created if missing when possible)
 - instructionsFilePath (string, optional): absolute path to a markdown instructions file injected at runtime
 - model (string, optional): Claude model id. Missing or blank defaults to ${DEFAULT_CLAUDE_LOCAL_MODEL} in both CLI and ACP, including existing agents. Explicit model IDs and ANTHROPIC_MODEL overrides are preserved. Bedrock/Vertex without an explicit model retain their provider default.
-- effort (string, optional): model-specific reasoning effort passed via --effort (low|medium|high; current Opus, Sonnet 5, and Fable models also support xhigh|max)
+- effort (string, optional): model-specific reasoning effort passed via --effort (low|medium|high; current Opus, Sonnet 5/5.5, and Fable models also support xhigh|max)
 - chrome (boolean, optional): pass --chrome when running Claude
 - promptTemplate (string, optional): run prompt template
 - maxTurnsPerRun (number, optional): max turns for one run
@@ -92,6 +93,7 @@ Operational fields:
 
 Notes:
 - Claude Opus 5.5 uses model ID \`claude-opus-5-5\` and requires Claude Code v2.1.280 or later.
+- Claude Sonnet 5.5 uses model ID \`claude-sonnet-5-5\` and requires Claude Code v2.1.284 or later.
 - filesystemScope and networkScope are spawn-level confinement and are orthogonal to Claude permission flags. Both require Bubblewrap on the host and explicit engine="cli"; default or explicit ACP is rejected because ACP confinement is not yet supported. networkScope="allowlist" injects HTTP_PROXY/HTTPS_PROXY for the CLI while its private network namespace blocks direct sockets, so every required provider/API hostname must be listed explicitly.
 - The Claude ACP lane requires Node >=24.11.0 and @agentclientprotocol/claude-agent-acp to be installed with this adapter package. Missing prerequisites fail both default and explicit ACP runs with an actionable setup error; the adapter never switches engines automatically.
 - For ACP runs, model selection is passed through ANTHROPIC_MODEL at ACP server startup; Paperclip-managed Claude permissions and ephemeral skill materialization are handled by the shared ACP engine.
diff --git a/packages/adapters/claude-local/src/server/cli-capabilities.ts b/packages/adapters/claude-local/src/server/cli-capabilities.ts
index 70da0cd3dc..dec74c2f38 100644
--- a/packages/adapters/claude-local/src/server/cli-capabilities.ts
+++ b/packages/adapters/claude-local/src/server/cli-capabilities.ts
@@ -38,6 +38,7 @@ function cacheKeyForTarget(command: string, target: AdapterExecutionTarget | nul
 export function minimumClaudeCliVersionForModel(model: string): string | null {
   const modelId = model.trim().replace(/\[1m\]$/, "").replace(/^(?:(?:us|eu|apac|global)\.)?anthropic\./, "");
   if (modelId === "claude-opus-5-5") return "2.1.280";
+  if (modelId === "claude-sonnet-5-5") return "2.1.284";
   return modelId === "claude-fable-5-1"
     ? CLAUDE_FABLE_5_1_MIN_CLI_VERSION
     : null;
diff --git a/packages/adapters/claude-local/src/server/execute.remote.test.ts b/packages/adapters/claude-local/src/server/execute.remote.test.ts
index d848ef6010..9ccc3ef77e 100644
--- a/packages/adapters/claude-local/src/server/execute.remote.test.ts
+++ b/packages/adapters/claude-local/src/server/execute.remote.test.ts
@@ -18,7 +18,7 @@ const {
     signal: null,
     timedOut: false,
     stdout: args.includes("--version")
-      ? "2.1.280 (Claude Code)\n"
+      ? "2.1.284 (Claude Code)\n"
       : [
           JSON.stringify({ type: "system", subtype: "init", session_id: "claude-session-1", model: "claude-sonnet" }),
           JSON.stringify({ type: "assistant", session_id: "claude-session-1", message: { content: [{ type: "text", text: "hello" }] } }),
@@ -467,7 +467,7 @@ describe("claude remote execution", () => {
       return { args: call?.[2] ?? [], result };
     }
 
-    it.each(["claude-fable-5-1", "claude-opus-5-5"])("passes %s as --model on the CLI lane", async (model) => {
+    it.each(["claude-fable-5-1", "claude-opus-5-5", "claude-sonnet-5-5"])("passes %s as --model on the CLI lane", async (model) => {
       const { args } = await executeWithModel("paperclip-claude-model-direct-", {
         model,
       });
@@ -500,6 +500,7 @@ describe("claude remote execution", () => {
     it.each([
       ["claude-fable-5-1", "2.1.251", "2.1.247"],
       ["claude-opus-5-5", "2.1.280", "2.1.279"],
+      ["claude-sonnet-5-5", "2.1.284", "2.1.283"],
     ])("rejects %s before launch below CLI %s", async (model, minimumVersion, detectedVersion) => {
       runChildProcess.mockResolvedValueOnce({
         exitCode: 0,
diff --git a/packages/adapters/claude-local/src/server/test.probe.test.ts b/packages/adapters/claude-local/src/server/test.probe.test.ts
index 817e39f34d..7273ca6adf 100644
--- a/packages/adapters/claude-local/src/server/test.probe.test.ts
+++ b/packages/adapters/claude-local/src/server/test.probe.test.ts
@@ -642,6 +642,7 @@ describe("claude CLI local hello probe hardening", () => {
   it.each([
     ["claude-fable-5-1", "2.1.251"],
     ["claude-opus-5-5", "2.1.280"],
+    ["claude-sonnet-5-5", "2.1.284"],
   ])("warns without executing %s when runtime PATH selects a different executable", async (model, minimumVersion) => {
     const runtimeDir = await mkdtemp(path.join(os.tmpdir(), "paperclip-cli-runtime-path-"));
     const runtimeClaudePath = path.join(runtimeDir, "claude");
diff --git a/packages/adapters/claude-local/src/server/test.remote.test.ts b/packages/adapters/claude-local/src/server/test.remote.test.ts
index 9062260e02..80ecd74ccc 100644
--- a/packages/adapters/claude-local/src/server/test.remote.test.ts
+++ b/packages/adapters/claude-local/src/server/test.remote.test.ts
@@ -144,6 +144,7 @@ describe("claude CLI model compatibility check", () => {
   it.each([
     ["claude-fable-5-1", "2.1.251", "2.1.247"],
     ["claude-opus-5-5", "2.1.280", "2.1.279"],
+    ["claude-sonnet-5-5", "2.1.284", "2.1.283"],
   ])("fails before the hello probe for %s below CLI %s", async (model, minimumVersion, detectedVersion) => {
     probeResult.value = {
       exitCode: 0,
diff --git a/packages/paperclip-runner/runner/crates/runner-core/src/acpx_provider_backend.rs b/packages/paperclip-runner/runner/crates/runner-core/src/acpx_provider_backend.rs
index 48f8ca0e79..eb25c8310a 100644
--- a/packages/paperclip-runner/runner/crates/runner-core/src/acpx_provider_backend.rs
+++ b/packages/paperclip-runner/runner/crates/runner-core/src/acpx_provider_backend.rs
@@ -153,7 +153,7 @@ impl AcpxProviderDescriptor {
                 "@agentclientprotocol/claude-agent-acp",
                 "0.73.0",
                 Some("@anthropic-ai/claude-agent-sdk"),
-                Some("0.3.280"),
+                Some("0.3.286"),
                 "sha256:9d73d1f0f121fb96cc8badb28c22d5bff02d8582eb2e40360a81c189e1b9422a",
             ),
             "codex" => (
@@ -2257,7 +2257,7 @@ mod tests {
                     "@agentclientprotocol/claude-agent-acp",
                     "0.73.0",
                     json!("@anthropic-ai/claude-agent-sdk"),
-                    json!("0.3.280"),
+                    json!("0.3.286"),
                     "sha256:9d73d1f0f121fb96cc8badb28c22d5bff02d8582eb2e40360a81c189e1b9422a",
                 )
             } else {
diff --git a/packages/paperclip-runner/runner/crates/runner-core/tests/native_provider_backend.rs b/packages/paperclip-runner/runner/crates/runner-core/tests/native_provider_backend.rs
index 9699a80278..493e413d99 100644
--- a/packages/paperclip-runner/runner/crates/runner-core/tests/native_provider_backend.rs
+++ b/packages/paperclip-runner/runner/crates/runner-core/tests/native_provider_backend.rs
@@ -266,7 +266,7 @@ fn pending_acpx_runtime_request(
         provider["agentServerPackage"] = json!("@agentclientprotocol/claude-agent-acp");
         provider["agentServerVersion"] = json!("0.73.0");
         provider["agentRuntimePackage"] = json!("@anthropic-ai/claude-agent-sdk");
-        provider["agentRuntimeVersion"] = json!("0.3.280");
+        provider["agentRuntimeVersion"] = json!("0.3.286");
         provider["commandDigest"] = json!(digest);
         provider["sidecarArgs"][3] = json!(digest);
     } else {
diff --git a/packages/paperclip-runner/src/backends/native-backend-factory.test.ts b/packages/paperclip-runner/src/backends/native-backend-factory.test.ts
index 2aa2addcd5..ca17d003e3 100644
--- a/packages/paperclip-runner/src/backends/native-backend-factory.test.ts
+++ b/packages/paperclip-runner/src/backends/native-backend-factory.test.ts
@@ -127,7 +127,7 @@ function acpxExecution(
               ? "@openai/codex"
               : "@anthropic-ai/claude-agent-sdk",
         agentRuntimeVersion:
-          agent === "pi" ? "0.84.2" : agent === "codex" ? "0.156.0" : "0.3.280",
+          agent === "pi" ? "0.84.2" : agent === "codex" ? "0.156.0" : "0.3.286",
         commandDigest:
           agent === "codex"
             ? "sha256:c4538599d1ab767db5dff50934f13bb5ba313a59d9c4a83e993fac4617ea63d3"
diff --git a/packages/paperclip-runner/src/drivers/acpx/installation-integrity.test.ts b/packages/paperclip-runner/src/drivers/acpx/installation-integrity.test.ts
index b97b7c51ac..f22dabdbe7 100644
--- a/packages/paperclip-runner/src/drivers/acpx/installation-integrity.test.ts
+++ b/packages/paperclip-runner/src/drivers/acpx/installation-integrity.test.ts
@@ -449,7 +449,7 @@ describe("ACPX installation integrity", () => {
       },
       {
         name: "@anthropic-ai/claude-agent-sdk",
-        version: "0.3.280",
+        version: "0.3.286",
         directory: join(dependencyRoot, "claude-agent-sdk"),
       },
       {
diff --git a/packages/paperclip-runner/src/drivers/acpx/installation-integrity.ts b/packages/paperclip-runner/src/drivers/acpx/installation-integrity.ts
index 237de315b4..1c17f6d67e 100644
--- a/packages/paperclip-runner/src/drivers/acpx/installation-integrity.ts
+++ b/packages/paperclip-runner/src/drivers/acpx/installation-integrity.ts
@@ -48,13 +48,13 @@ const VERIFIED_PROVIDER_RUNTIME_TARGET_ENV =
 
 const QUALIFIED_CLAUDE_LINUX_X64_RUNTIME = Object.freeze({
   runtimePackageName: "@anthropic-ai/claude-agent-sdk",
-  runtimePackageVersion: "0.3.280",
+  runtimePackageVersion: "0.3.286",
   packageName: "@anthropic-ai/claude-agent-sdk-linux-x64",
-  packageVersion: "0.3.280",
-  dependencyDeclaration: "0.3.280",
+  packageVersion: "0.3.286",
+  dependencyDeclaration: "0.3.286",
   relativeExecutable: "claude",
   executableDigest:
-    "sha256:1e08503dbdf3c2cb0d706d32f3408277388d1c76ef108673e8fe42c1b322925b",
+    "sha256:fe503f65c6289d59c23e5b21ae44f03583f997dd33a2cbfc75ab4f96fb8fc73f",
   environmentVariable: "CLAUDE_CODE_EXECUTABLE",
 });
 
@@ -62,12 +62,12 @@ const QUALIFIED_CLAUDE_DARWIN_RUNTIMES = {
   arm64: Object.freeze({
     ...QUALIFIED_CLAUDE_LINUX_X64_RUNTIME,
     packageName: "@anthropic-ai/claude-agent-sdk-darwin-arm64",
-    executableDigest: "sha256:387a5c5dcdbb815085edf0baf79591f9d8894efe922bceaf3d75b1b08055229d",
+    executableDigest: "sha256:75e3016e9d2570767b08e43a7467d4817a4f149232c169ca295f2c95fef21433",
   }),
   x64: Object.freeze({
     ...QUALIFIED_CLAUDE_LINUX_X64_RUNTIME,
     packageName: "@anthropic-ai/claude-agent-sdk-darwin-x64",
-    executableDigest: "sha256:c1d32d87630482250633208ab77855429b24010ae3086a7ff7539b57b93168d4",
+    executableDigest: "sha256:53e6a936e89519d695230f9cc97943991286b72766674fba11bee845f0a7c047",
   }),
 };
 
@@ -95,8 +95,8 @@ const QUALIFIED_CLAUDE_PROVIDER_DEPENDENCIES = Object.freeze([
   }),
   Object.freeze({
     packageName: "@anthropic-ai/claude-agent-sdk",
-    packageVersion: "0.3.280",
-    // The package's own package.json still declares 0.3.257 — 0.3.280 is
+    packageVersion: "0.3.286",
+    // The package's own package.json still declares 0.3.257 — 0.3.286 is
     // only what pnpm resolves, forced by the
     // "claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk" override in
     // the workspace root. This field binds the declared string, not the
diff --git a/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.test.ts b/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.test.ts
index 9cde5dd0a9..f4bab678e4 100644
--- a/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.test.ts
+++ b/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.test.ts
@@ -41,7 +41,7 @@ describe("qualified ACPX profiles", () => {
   it("binds Claude ACP to the SDK and native CLI runtime it launches", () => {
     expect(QUALIFIED_ACPX_PROFILES.claude).toMatchObject({
       agentRuntimePackage: "@anthropic-ai/claude-agent-sdk",
-      agentRuntimeVersion: "0.3.280",
+      agentRuntimeVersion: "0.3.286",
     });
   });
 });
diff --git a/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.ts b/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.ts
index b7b5f39898..5232991139 100644
--- a/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.ts
+++ b/packages/paperclip-runner/src/drivers/acpx/qualified-profiles.ts
@@ -89,7 +89,7 @@ export const QUALIFIED_ACPX_PROFILES: Readonly<
     agentServerPackage: "@agentclientprotocol/claude-agent-acp",
     agentServerVersion: "0.73.0",
     agentRuntimePackage: "@anthropic-ai/claude-agent-sdk",
-    agentRuntimeVersion: "0.3.280",
+    agentRuntimeVersion: "0.3.286",
     commandDigest:
       "sha256:9d73d1f0f121fb96cc8badb28c22d5bff02d8582eb2e40360a81c189e1b9422a",
     qualificationModel: "claude-sonnet-5",
diff --git a/packages/paperclip-runner/test/acpx-codex-package-contract.test.mjs b/packages/paperclip-runner/test/acpx-codex-package-contract.test.mjs
index 3868dda6c5..37e317f92a 100644
--- a/packages/paperclip-runner/test/acpx-codex-package-contract.test.mjs
+++ b/packages/paperclip-runner/test/acpx-codex-package-contract.test.mjs
@@ -60,7 +60,7 @@ test("the runner pins every qualified ACPX production dependency", () => {
   assert.equal(runnerPackage.dependencies["@openai/codex"], "0.156.0");
   assert.equal(runnerPackage.dependencies["@anthropic-ai/claude-agent-sdk"], undefined);
   assert.equal(rootPackage.pnpm.overrides["@agentclientprotocol/codex-acp@1.6.2>@openai/codex"], runnerPackage.dependencies["@openai/codex"]);
-  assert.equal(rootPackage.pnpm.overrides["@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk"], "0.3.280");
+  assert.equal(rootPackage.pnpm.overrides["@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk"], "0.3.286");
   assert.equal(runnerPackage.optionalDependencies, undefined);
   assert.equal(runnerPackage.dependencies.node, undefined);
   assert.equal(runnerPackage.dependencies.acpx, "0.13.1");
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index 19900634e4..f5c8f084bc 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -33,7 +33,7 @@ patchedDependencies:
 # pnpm patches change package files, but overrides control dependency resolution.
 overrides:
   "@agentclientprotocol/codex-acp@1.6.2>@openai/codex": "0.156.0"
-  "@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk": "0.3.280"
+  "@agentclientprotocol/claude-agent-acp@0.73.0>@anthropic-ai/claude-agent-sdk": "0.3.286"
   rollup: ">=4.59.0"
   react: "^19.2.8"
   react-dom: "^19.2.8"
diff --git a/server/src/__tests__/adapter-models.test.ts b/server/src/__tests__/adapter-models.test.ts
index 98ec099837..a8f736a5df 100644
--- a/server/src/__tests__/adapter-models.test.ts
+++ b/server/src/__tests__/adapter-models.test.ts
@@ -72,6 +72,7 @@ describe("adapter model listing", () => {
     // Opus 5 is a current GA flagship and must be offered even when live discovery is unavailable.
     expect(models.some((model) => model.id === "claude-opus-5")).toBe(true);
     expect(models).toContainEqual({ id: "claude-opus-5-5", label: "Claude Opus 5.5" });
+    expect(models).toContainEqual({ id: "claude-sonnet-5-5", label: "Claude Sonnet 5.5" });
     expect(fetchSpy).not.toHaveBeenCalled();
   });
 
@@ -95,6 +96,7 @@ describe("adapter model listing", () => {
     expect(first.some((model) => model.id === "claude-opus-4-8-20260529")).toBe(true);
     expect(first.some((model) => model.id === "claude-opus-4-8")).toBe(true);
     expect(first.some((model) => model.id === "claude-opus-5-5")).toBe(true);
+    expect(first.some((model) => model.id === "claude-sonnet-5-5")).toBe(true);
     // Discovered models take the curated order too: the API's order is not shown as-is.
     const firstIds = first.map((model) => model.id);
     expect(firstIds[0]).toBe("claude-fable-5-1");
@@ -141,6 +143,7 @@ describe("adapter model listing", () => {
   it.each([
     ["claude-fable-5-1", "Claude Fable 5.1"],
     ["claude-opus-5-5", "Claude Opus 5.5"],
+    ["claude-sonnet-5-5", "Claude Sonnet 5.5"],
   ])("does not duplicate %s when discovery returns the identical ID", async (id, displayName) => {
     process.env.ANTHROPIC_API_KEY = "sk-ant-test";
     vi.spyOn(globalThis, "fetch").mockResolvedValue({
diff --git a/ui/src/lib/agent-setup-fields.test.ts b/ui/src/lib/agent-setup-fields.test.ts
index e0d14f7e7d..2b3b3773c2 100644
--- a/ui/src/lib/agent-setup-fields.test.ts
+++ b/ui/src/lib/agent-setup-fields.test.ts
@@ -5,6 +5,8 @@ import { setupEfforts } from "./agent-setup-fields";
 describe("model-specific setup efforts", () => {
   it("offers current Claude efforts without offering them on Haiku", () => {
     expect(setupEfforts("claude_local", "claude-fable-5-1")).toEqual(["low", "medium", "high", "xhigh", "max"]);
+    expect(setupEfforts("claude_local", "claude-sonnet-5-5")).toEqual(["low", "medium", "high", "xhigh", "max"]);
+    expect(setupEfforts("claude_local", "claude-opus-5-5")).toEqual(["low", "medium", "high", "xhigh", "max"]);
     expect(setupEfforts("claude_local", "claude-haiku-4-5")).toEqual([]);
   });