diff --git a/apps/sidecar/src/rpc/channel-handlers.ts b/apps/sidecar/src/rpc/channel-handlers.ts
index e28994ba6..56800b410 100644
--- a/apps/sidecar/src/rpc/channel-handlers.ts
+++ b/apps/sidecar/src/rpc/channel-handlers.ts
@@ -12,12 +12,17 @@ import {
   updateChannel
 } from "../services/channel/channel-manager";
 import type { RpcHandler } from "./types";
-import { asObject, asString, validateInput } from "./validation";
+import { validateInput } from "./validation";
 import {
+  channelIdParamsSchema,
   channelCreateInputSchema,
   channelDeleteParamsSchema,
   channelUpdateParamsSchema,
-  fetchModelsInputSchema
+  connectionIdParamsSchema,
+  fetchModelsInputSchema,
+  oauthAnswerParamsSchema,
+  oauthCancelParamsSchema,
+  oauthSessionIdParamsSchema
 } from "./schemas";
 import {
   answerConnectionOAuthPrompt,
@@ -41,52 +46,36 @@ export function createChannelHandlers(): Record<string, RpcHandler> {
       return { ok: true };
     },
     [CHANNEL_IPC_CHANNELS.DECRYPT_KEY]: async (params) => {
-      const payload = asObject(params);
-      const channelId = asString(payload.channelId);
-      if (!channelId) {
-        throw new Error("缺少 channelId");
-      }
-      return decryptApiKey(channelId);
+      const input = validateInput(channelIdParamsSchema, params, CHANNEL_IPC_CHANNELS.DECRYPT_KEY);
+      return decryptApiKey(input.channelId);
     },
     [CHANNEL_IPC_CHANNELS.TEST]: async (params) => {
-      const payload = asObject(params);
-      const channelId = asString(payload.channelId);
-      if (!channelId) {
-        throw new Error("缺少 channelId");
-      }
-      return testChannel(channelId);
+      const input = validateInput(channelIdParamsSchema, params, CHANNEL_IPC_CHANNELS.TEST);
+      return testChannel(input.channelId);
     },
     [CHANNEL_IPC_CHANNELS.TEST_DIRECT]: async (params) =>
       testChannelDirect(validateInput(fetchModelsInputSchema, params, CHANNEL_IPC_CHANNELS.TEST_DIRECT) as FetchModelsInput),
     [CHANNEL_IPC_CHANNELS.FETCH_MODELS]: async (params) =>
       fetchModels(validateInput(fetchModelsInputSchema, params, CHANNEL_IPC_CHANNELS.FETCH_MODELS) as FetchModelsInput),
     [CHANNEL_IPC_CHANNELS.SYNC_MODELS]: async (params) => {
-      const payload = asObject(params);
-      const channelId = asString(payload.channelId);
-      if (!channelId) throw new Error("缺少 channelId");
-      return syncChannelModels(channelId);
+      const input = validateInput(channelIdParamsSchema, params, CHANNEL_IPC_CHANNELS.SYNC_MODELS);
+      return syncChannelModels(input.channelId);
     },
     [CHANNEL_IPC_CHANNELS.OAUTH_START]: async (params) => {
-      const connectionId = asString(asObject(params).connectionId);
-      if (!connectionId) throw new Error("缺少 connectionId");
-      return startConnectionOAuthLogin(connectionId);
+      const input = validateInput(connectionIdParamsSchema, params, CHANNEL_IPC_CHANNELS.OAUTH_START);
+      return startConnectionOAuthLogin(input.connectionId);
     },
     [CHANNEL_IPC_CHANNELS.OAUTH_STATUS]: async (params) => {
-      const sessionId = asString(asObject(params).sessionId);
-      if (!sessionId) throw new Error("缺少 sessionId");
-      return getConnectionOAuthSession(sessionId);
+      const input = validateInput(oauthSessionIdParamsSchema, params, CHANNEL_IPC_CHANNELS.OAUTH_STATUS);
+      return getConnectionOAuthSession(input.sessionId);
     },
     [CHANNEL_IPC_CHANNELS.OAUTH_ANSWER]: async (params) => {
-      const payload = asObject(params);
-      const sessionId = asString(payload.sessionId);
-      const promptId = asString(payload.promptId);
-      const value = asString(payload.value);
-      if (!sessionId || !promptId) throw new Error("缺少 OAuth prompt 参数");
-      return answerConnectionOAuthPrompt(sessionId, promptId, value ?? "");
+      const input = validateInput(oauthAnswerParamsSchema, params, CHANNEL_IPC_CHANNELS.OAUTH_ANSWER);
+      return answerConnectionOAuthPrompt(input.sessionId, input.promptId, input.value ?? "");
     },
     [CHANNEL_IPC_CHANNELS.OAUTH_CANCEL]: async (params) => {
-      const sessionId = asString(asObject(params).sessionId);
-      if (sessionId) cancelConnectionOAuthLogin(sessionId);
+      const input = validateInput(oauthCancelParamsSchema, params, CHANNEL_IPC_CHANNELS.OAUTH_CANCEL);
+      if (input.sessionId) cancelConnectionOAuthLogin(input.sessionId);
       return { ok: true };
     },
   };
diff --git a/apps/sidecar/src/rpc/schemas.channel-params.test.ts b/apps/sidecar/src/rpc/schemas.channel-params.test.ts
new file mode 100644
index 000000000..f0efda30e
--- /dev/null
+++ b/apps/sidecar/src/rpc/schemas.channel-params.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, test } from "bun:test";
+import {
+  channelIdParamsSchema,
+  connectionIdParamsSchema,
+  oauthAnswerParamsSchema,
+  oauthCancelParamsSchema,
+  oauthSessionIdParamsSchema
+} from "./schemas";
+
+describe("channel RPC param schemas", () => {
+  test("channelIdParamsSchema accepts a non-empty channelId", () => {
+    expect(channelIdParamsSchema.parse({ channelId: "ch-1" })).toEqual({ channelId: "ch-1" });
+  });
+
+  test("channelIdParamsSchema rejects missing and empty channelId", () => {
+    expect(channelIdParamsSchema.safeParse({}).success).toBe(false);
+    expect(channelIdParamsSchema.safeParse({ channelId: "" }).success).toBe(false);
+    expect(channelIdParamsSchema.safeParse({ channelId: 42 }).success).toBe(false);
+  });
+
+  test("param schemas reject unknown keys like the sibling channel schemas", () => {
+    expect(channelIdParamsSchema.safeParse({ channelId: "ch-1", extra: true }).success).toBe(false);
+    expect(connectionIdParamsSchema.safeParse({ connectionId: "conn-1", channelId: "x" }).success).toBe(false);
+  });
+
+  test("oauthSessionIdParamsSchema requires a non-empty sessionId", () => {
+    expect(oauthSessionIdParamsSchema.parse({ sessionId: "s-1" }).sessionId).toBe("s-1");
+    expect(oauthSessionIdParamsSchema.safeParse({ sessionId: "" }).success).toBe(false);
+  });
+
+  test("oauthAnswerParamsSchema keeps value optional and ids required", () => {
+    expect(oauthAnswerParamsSchema.parse({ sessionId: "s-1", promptId: "p-1" }).value).toBeUndefined();
+    expect(oauthAnswerParamsSchema.parse({ sessionId: "s-1", promptId: "p-1", value: "yes" }).value).toBe("yes");
+    expect(oauthAnswerParamsSchema.safeParse({ sessionId: "s-1" }).success).toBe(false);
+  });
+
+  test("oauthCancelParamsSchema tolerates an absent sessionId (legacy no-op face)", () => {
+    expect(oauthCancelParamsSchema.parse({})).toEqual({});
+    expect(oauthCancelParamsSchema.parse({ sessionId: "s-1" }).sessionId).toBe("s-1");
+    expect(oauthCancelParamsSchema.safeParse({ sessionId: "" }).success).toBe(false);
+  });
+});
diff --git a/apps/sidecar/src/rpc/schemas.ts b/apps/sidecar/src/rpc/schemas.ts
index b2af2f064..1a197bcb8 100644
--- a/apps/sidecar/src/rpc/schemas.ts
+++ b/apps/sidecar/src/rpc/schemas.ts
@@ -1818,3 +1818,17 @@ export const fetchModelsInputSchema = z.object({
   apiFamily: channelApiFamilySchema.optional(),
   openaiApiMode: channelOpenAiApiModeSchema.optional()
 }).strict();
+
+export const channelIdParamsSchema = z.object({ channelId: idSchema }).strict();
+
+export const connectionIdParamsSchema = z.object({ connectionId: idSchema }).strict();
+
+export const oauthSessionIdParamsSchema = z.object({ sessionId: idSchema }).strict();
+
+export const oauthAnswerParamsSchema = z.object({
+  sessionId: idSchema,
+  promptId: idSchema,
+  value: z.string().optional()
+}).strict();
+
+export const oauthCancelParamsSchema = z.object({ sessionId: idSchema.optional() }).strict();
diff --git a/apps/sidecar/src/services/agent-runtime/context/context-assembler.ts b/apps/sidecar/src/services/agent-runtime/context/context-assembler.ts
index f29aff42d..78f42c03a 100644
--- a/apps/sidecar/src/services/agent-runtime/context/context-assembler.ts
+++ b/apps/sidecar/src/services/agent-runtime/context/context-assembler.ts
@@ -17,7 +17,6 @@ import type { MemoryV2RecallItem } from "../../memory-v2/types";
 import type { CollectedAppendContextEffect } from "../../workflow-hooks/hook-effects";
 import { getPermissionDeniedSummary } from "../permissions/permission-denials";
 import type { TraceRecorder } from "../trace/trace-recorder";
-import { DEFAULT_CONTEXT_BUDGET, type ContextBudget } from "./context-budget";
 import { buildMessageAttachmentBrief } from "./message-attachments";
 
 export interface ContextAssemblyInput {
@@ -71,7 +70,7 @@ export interface ContextAssemblyResult {
   userMessageContentBlocks?: ContentBlockParam[];
   sessionContext: string;
   planContext?: string;
-  budget: ContextBudget;
+  budget: { total: number };
   trace: {
     includedMemoryIds: string[];
     includedSessionMessageIds: string[];
@@ -341,7 +340,6 @@ Browser annotation bodies are the user's intent. URL, title, DOM locators, selec
       userMessageForModel,
       sessionContext: "",
       budget: {
-        ...DEFAULT_CONTEXT_BUDGET,
         total: input.tokenBudget
       },
       trace: {
diff --git a/apps/sidecar/src/services/agent-runtime/context/context-budget.ts b/apps/sidecar/src/services/agent-runtime/context/context-budget.ts
deleted file mode 100644
index d1b1f2223..000000000
--- a/apps/sidecar/src/services/agent-runtime/context/context-budget.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-export interface ContextBudget {
-  total: number;
-  system: number;
-  dynamic: number;
-  memory: number;
-  session: number;
-  toolSchemas: number;
-  reservedOutput: number;
-}
-
-export const DEFAULT_CONTEXT_BUDGET: ContextBudget = {
-  total: 1,
-  system: 0.25,
-  dynamic: 0.15,
-  memory: 0.20,
-  session: 0.25,
-  toolSchemas: 0.10,
-  reservedOutput: 0.05
-};
diff --git a/apps/sidecar/src/services/agent/prompt/sections/section-composer.test.ts b/apps/sidecar/src/services/agent/prompt/sections/section-composer.test.ts
deleted file mode 100644
index 61bdefe69..000000000
--- a/apps/sidecar/src/services/agent/prompt/sections/section-composer.test.ts
+++ /dev/null
@@ -1,32 +0,0 @@
-import { describe, expect, test } from "bun:test";
-import { composePromptSections } from "./section-composer";
-
-describe("section-composer", () => {
-  test("filters by mode and renders in priority order", () => {
-    const prompt = composePromptSections([
-      {
-        id: "later",
-        title: "Later",
-        priority: 20,
-        mode: ["full"],
-        content: "B"
-      },
-      {
-        id: "minimal",
-        title: "Minimal",
-        priority: 5,
-        mode: ["minimal"],
-        content: "skip"
-      },
-      {
-        id: "first",
-        title: "First",
-        priority: 10,
-        mode: ["full", "minimal"],
-        content: "A"
-      }
-    ], "full");
-
-    expect(prompt).toBe("## First\n\nA\n\n## Later\n\nB");
-  });
-});
diff --git a/apps/sidecar/src/services/agent/prompt/sections/section-composer.ts b/apps/sidecar/src/services/agent/prompt/sections/section-composer.ts
deleted file mode 100644
index 02638da6c..000000000
--- a/apps/sidecar/src/services/agent/prompt/sections/section-composer.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-import type { PromptSection, PromptSectionMode } from "../types";
-
-export function renderPromptSection(section: PromptSection): string {
-  if (section.title) {
-    return `## ${section.title}\n\n${section.content.trim()}`;
-  }
-  return section.content.trim();
-}
-
-export function composePromptSections(
-  sections: Array<PromptSection | null | undefined>,
-  mode: PromptSectionMode
-): string {
-  return sections
-    .filter((section): section is PromptSection => Boolean(section?.content.trim()))
-    .filter((section) => section.mode.includes(mode))
-    .sort((a, b) => a.priority - b.priority)
-    .map(renderPromptSection)
-    .join("\n\n");
-}
diff --git a/apps/sidecar/src/services/agent/prompt/types.ts b/apps/sidecar/src/services/agent/prompt/types.ts
deleted file mode 100644
index 995baff78..000000000
--- a/apps/sidecar/src/services/agent/prompt/types.ts
+++ /dev/null
@@ -1,10 +0,0 @@
-export type PromptSectionMode = "full" | "minimal";
-
-export interface PromptSection {
-  id: string;
-  title?: string;
-  priority: number;
-  mode: PromptSectionMode[];
-  content: string;
-  tokenBudget?: number;
-}
diff --git a/apps/sidecar/src/services/model-runtime/pi-ai-provider.test.ts b/apps/sidecar/src/services/model-runtime/pi-ai-provider.test.ts
index 8d1ee53a8..05dcf3f2d 100644
--- a/apps/sidecar/src/services/model-runtime/pi-ai-provider.test.ts
+++ b/apps/sidecar/src/services/model-runtime/pi-ai-provider.test.ts
@@ -44,7 +44,7 @@ describe("pi-ai provider retry policy", () => {
     expect(isRetryablePiAiError(new PiAiProviderError("invalid key", { status: 401 }))).toBe(false);
   });
 
-  test("uses 1/2/4/8/16 second backoff and caps Retry-After at 30 seconds", () => {
+  test("uses 1/2/4/8/16 second backoff and caps Retry-After at 120 seconds", () => {
     const deterministicRandom = () => 0.5;
     expect([0, 1, 2, 3, 4].map((index) =>
       resolvePiAiRetryDelayMs(new Error("network"), index, deterministicRandom)
@@ -53,7 +53,12 @@ describe("pi-ai provider retry policy", () => {
       new PiAiProviderError("busy", { retryAfterMs: 90_000 }),
       0,
       deterministicRandom,
-    )).toBe(30_000);
+    )).toBe(90_000);
+    expect(resolvePiAiRetryDelayMs(
+      new PiAiProviderError("busy", { retryAfterMs: 300_000 }),
+      0,
+      deterministicRandom,
+    )).toBe(120_000);
   });
 
   test("falls back for model-specific and credential failures but not malformed requests", () => {
diff --git a/apps/sidecar/src/services/model-runtime/pi-ai-provider.ts b/apps/sidecar/src/services/model-runtime/pi-ai-provider.ts
index f77becdbe..b4c3c9cfa 100644
--- a/apps/sidecar/src/services/model-runtime/pi-ai-provider.ts
+++ b/apps/sidecar/src/services/model-runtime/pi-ai-provider.ts
@@ -21,12 +21,12 @@ import type {
   NormalizedMessageParam,
   NormalizedResponseBlock,
 } from "@lume/agent-sdk";
+import { MAX_RETRY_AFTER_DELAY_MS, parseRetryAfterHeader } from "@lume/agent-sdk";
 
 type PiTextApi = "openai-completions" | "openai-responses" | "openai-codex-responses" | "anthropic-messages" | "google-generative-ai";
 
 const DEFAULT_MAX_RETRIES = 5;
 const RETRY_DELAYS_MS = [1_000, 2_000, 4_000, 8_000, 16_000] as const;
-const MAX_RETRY_AFTER_MS = 30_000;
 
 export interface PiAiProviderOptions {
   apiType: ApiType;
@@ -80,7 +80,7 @@ export function resolvePiAiRetryDelayMs(error: unknown, retryIndex: number, rand
   const base = RETRY_DELAYS_MS[Math.min(retryIndex, RETRY_DELAYS_MS.length - 1)] ?? RETRY_DELAYS_MS.at(-1)!;
   const jittered = Math.round(base * (0.8 + random() * 0.4));
   const retryAfter = typeof (error as { retryAfterMs?: unknown } | null)?.retryAfterMs === "number"
-    ? Math.min(MAX_RETRY_AFTER_MS, Math.max(0, (error as { retryAfterMs: number }).retryAfterMs))
+    ? Math.min(MAX_RETRY_AFTER_DELAY_MS, Math.max(0, (error as { retryAfterMs: number }).retryAfterMs))
     : 0;
   return Math.max(jittered, retryAfter);
 }
@@ -288,12 +288,7 @@ function toResponse(message: AssistantMessage): CreateMessageResponse {
 }
 
 function retryAfterMs(headers: Record<string, string> | undefined): number | undefined {
-  const raw = headers?.["retry-after"] ?? headers?.["Retry-After"];
-  if (!raw) return undefined;
-  const seconds = Number(raw);
-  if (Number.isFinite(seconds)) return Math.max(0, seconds * 1000);
-  const date = Date.parse(raw);
-  return Number.isFinite(date) ? Math.max(0, date - Date.now()) : undefined;
+  return parseRetryAfterHeader(headers?.["retry-after"] ?? headers?.["Retry-After"]);
 }
 
 function structuredOutputTransform(api: PiTextApi, schema: Record<string, unknown> | undefined) {
@@ -377,7 +372,7 @@ export class PiAiProvider implements LLMProvider {
           signal: params.abortSignal,
           maxTokens: params.maxTokens,
           maxRetries: 0,
-          maxRetryDelayMs: MAX_RETRY_AFTER_MS,
+          maxRetryDelayMs: MAX_RETRY_AFTER_DELAY_MS,
           sessionId: this.options.sessionId ?? params.promptCache?.routingKey,
           cacheRetention: params.promptCache?.ttl === "5m" ? "short" : "none",
           ...(params.thinking?.type === "disabled" ? {} : { reasoning: params.effort ?? "medium" }),
diff --git a/packages/sdk/src/index.ts b/packages/sdk/src/index.ts
index f7d3ce564..d7a8347db 100644
--- a/packages/sdk/src/index.ts
+++ b/packages/sdk/src/index.ts
@@ -391,6 +391,9 @@ export {
   isRateLimitError,
   formatApiError,
   getRetryDelay,
+  computeRetryDelay,
+  parseRetryAfterHeader,
+  MAX_RETRY_AFTER_DELAY_MS,
   DEFAULT_RETRY_CONFIG,
 } from './utils/retry.js'
 export type { RetryConfig } from './utils/retry.js'