diff --git a/src/main/agent/opencode-runtime.ts b/src/main/agent/opencode-runtime.ts
index d9dd8cf5..7cf9763e 100644
--- a/src/main/agent/opencode-runtime.ts
+++ b/src/main/agent/opencode-runtime.ts
@@ -1,11 +1,11 @@
 import { runtimeChecklistSchema, type RuntimeChecklist } from '../../shared/runtime-checklist';
-import {
+import type {
   createOpencodeClient,
-  type AssistantMessage,
-  type OpencodeClient,
-  type PermissionRequest,
-  type PermissionRuleset,
-  type QuestionRequest,
+  AssistantMessage,
+  OpencodeClient,
+  PermissionRequest,
+  PermissionRuleset,
+  QuestionRequest,
 } from "@opencode-ai/sdk/v2";
 import spawn from "cross-spawn";
 import { createHash, randomBytes } from "node:crypto";
@@ -740,11 +740,27 @@ async function defaultValidateBinary(
   });
 }
 
+type OpencodeSdk = typeof import("@opencode-ai/sdk/v2");
+let opencodeSdk: OpencodeSdk | undefined;
+
+// The SDK is loaded when an OpenCode client is first created, not at Main
+// startup (P6). initializeClient awaits this before any default factory runs.
+async function loadOpencodeSdk(): Promise<OpencodeSdk> {
+  opencodeSdk ??= await import("@opencode-ai/sdk/v2");
+  return opencodeSdk;
+}
+
+const defaultCreateClient: typeof createOpencodeClient = (config) => {
+  if (!opencodeSdk) throw new Error("OpenCode SDK is not loaded");
+  return opencodeSdk.createOpencodeClient(config);
+};
+
 async function defaultCheckServerHealth(
   url: string,
   authorization: string,
   signal: AbortSignal,
 ): Promise<boolean> {
+  const { createOpencodeClient } = await loadOpencodeSdk();
   const client = createOpencodeClient({
     baseUrl: url,
     headers: { Authorization: authorization },
@@ -798,7 +814,7 @@ export class OpenCodeRuntime implements AgentRuntime {
       spawn,
       detectBinary: defaultDetectBinary,
       validateBinary: defaultValidateBinary,
-      createClient: createOpencodeClient,
+      createClient: defaultCreateClient,
       checkServerHealth: defaultCheckServerHealth,
       platform: process.platform,
       startupTimeoutMs: STARTUP_TIMEOUT_MS,
@@ -1483,6 +1499,7 @@ export class OpenCodeRuntime implements AgentRuntime {
     if (baseUrl && this.options.modelProfile) {
       throw new Error("OpenCode 独立模型连接仅支持由 GoodBuddy 启动的本机服务");
     }
+    await loadOpencodeSdk();
     if (!baseUrl && this.options.embedded) {
       this.server = await this.launchEmbedded(signal);
       baseUrl = this.server.url;
diff --git a/src/main/document-extracted-text.ts b/src/main/document-extracted-text.ts
index da333df2..b85b09b6 100644
--- a/src/main/document-extracted-text.ts
+++ b/src/main/document-extracted-text.ts
@@ -1,8 +1,15 @@
-import { convert } from 'html-to-text'
+import { createLazyRequire } from './lazy-require'
+
+/**
+ * Loads html-to-text on first use instead of at Main startup (P6, ~45 ms).
+ * Synchronous so the text checks keep their signatures.
+ */
+export const loadHtmlToText =
+  createLazyRequire<typeof import('html-to-text')>('html-to-text')
 
 export function hasExtractedDocumentText(content: string): boolean {
   const text = content
     .replace(/!\[[^\]]*\]\([^)]*\)/gu, '')
     .replace(/\[第 \d+ 页图片未保存：[^\]]*\]/gu, '')
-  return Boolean(convert(text, { wordwrap: false }).trim())
+  return Boolean(loadHtmlToText().convert(text, { wordwrap: false }).trim())
 }
diff --git a/src/main/document-result-storage.ts b/src/main/document-result-storage.ts
index 3c7b18be..ef8d02fd 100644
--- a/src/main/document-result-storage.ts
+++ b/src/main/document-result-storage.ts
@@ -1,7 +1,6 @@
 import { randomUUID } from 'node:crypto'
 import { mkdir, readFile, rename, rm, writeFile } from 'node:fs/promises'
 import { basename, dirname, extname, join } from 'node:path'
-import { createCanvas, loadImage } from '@napi-rs/canvas'
 import { documentResultSchema, type DocumentResult } from '../shared/document-result-contracts'
 import type { DocumentParsingSettings } from '../shared/document-parsing-contracts'
 import type { ParsedDocument } from './knowledge/document-parser'
@@ -96,6 +95,8 @@ export class DocumentResultStorage {
     if (!image) throw new Error('解析图片不存在')
     const data = await readFile(join(this.require(id).directory, 'images', imageId))
     if (thumbnail) {
+      // Native canvas loads on first use (P6).
+      const { createCanvas, loadImage } = await import('@napi-rs/canvas')
       const source = await loadImage(data)
       const scale = Math.min(1, 640 / Math.max(source.width, source.height))
       const canvas = createCanvas(Math.max(1, Math.round(source.width * scale)), Math.max(1, Math.round(source.height * scale)))
diff --git a/src/main/http-document-ocr.ts b/src/main/http-document-ocr.ts
index 7c2c34f9..c87a8837 100644
--- a/src/main/http-document-ocr.ts
+++ b/src/main/http-document-ocr.ts
@@ -1,5 +1,4 @@
 import { randomUUID } from 'node:crypto'
-import { loadImage } from '@napi-rs/canvas'
 import { z } from 'zod'
 import {
   maximumDocumentExtractedCharacters,
@@ -131,6 +130,8 @@ export class HttpDocumentOcr {
             : bytes.subarray(0, 8).equals(Buffer.from([137, 80, 78, 71, 13, 10, 26, 10])) ? 'image/png'
               : bytes.toString('ascii', 0, 4) === 'RIFF' && bytes.toString('ascii', 8, 12) === 'WEBP' ? 'image/webp' : undefined
           if (!mimeType) throw new Error('图片格式不支持')
+          // Native canvas loads on first use (P6).
+          const { loadImage } = await import('@napi-rs/canvas')
           const image = await loadImage(bytes)
           if (!image.width || !image.height || image.width * image.height > 40_000_000) throw new Error('图片尺寸无效或超过 4000 万像素')
           imageBytes += bytes.length
diff --git a/src/main/knowledge/document-parser.ts b/src/main/knowledge/document-parser.ts
index 6b40b217..7f833c1f 100644
--- a/src/main/knowledge/document-parser.ts
+++ b/src/main/knowledge/document-parser.ts
@@ -1,4 +1,4 @@
-import { convert } from 'html-to-text'
+import { loadHtmlToText } from '../document-extracted-text'
 import { unzipSync } from 'fflate'
 import { extname } from 'node:path'
 import type { ParsedDocumentImage } from '../http-document-ocr'
@@ -701,7 +701,7 @@ export async function parseDocument(
   } else if (['.docx', '.xlsx', '.pptx'].includes(extension)) {
     sections = parseOfficeArchive(buffer, extension)
   } else if (['.html', '.htm'].includes(extension)) {
-    const content = convert(decodeText(buffer), {
+    const content = loadHtmlToText().convert(decodeText(buffer), {
       wordwrap: false,
       selectors: [
         { selector: 'script', format: 'skip' },
diff --git a/src/main/lazy-require.test.ts b/src/main/lazy-require.test.ts
new file mode 100644
index 00000000..f5694a3f
--- /dev/null
+++ b/src/main/lazy-require.test.ts
@@ -0,0 +1,24 @@
+// @vitest-environment node
+import { describe, expect, it } from 'vitest'
+import { createLazyRequire } from './lazy-require'
+import { loadHtmlToText } from './document-extracted-text'
+import { loadSsh2 } from './ssh/ssh2-module'
+
+describe('createLazyRequire', () => {
+  it('loads a module on first call and returns the cached instance afterwards', () => {
+    const load = createLazyRequire<typeof import('node:path')>('node:path')
+    const first = load()
+    expect(typeof first.join).toBe('function')
+    expect(load()).toBe(first)
+  })
+
+  it('surfaces a missing module at first use, not at import time', () => {
+    const load = createLazyRequire('goodbuddy-module-that-does-not-exist')
+    expect(load).toThrow()
+  })
+
+  it('resolves the deferred Main dependencies', () => {
+    expect(typeof loadHtmlToText().convert).toBe('function')
+    expect(typeof loadSsh2().Client).toBe('function')
+  })
+})
diff --git a/src/main/lazy-require.ts b/src/main/lazy-require.ts
new file mode 100644
index 00000000..afddefb8
--- /dev/null
+++ b/src/main/lazy-require.ts
@@ -0,0 +1,14 @@
+import { createRequire } from 'node:module'
+
+/**
+ * Synchronously loads a dependency on first use instead of at module
+ * evaluation (P6). Main is ESM, but some test fixtures bundle the same code as
+ * CommonJS, where `import.meta.url` is empty and `__filename` exists instead.
+ */
+export function createLazyRequire<T>(specifier: string): () => T {
+  let loaded: T | undefined
+  return () => {
+    loaded ??= createRequire(import.meta.url || __filename)(specifier) as T
+    return loaded
+  }
+}
diff --git a/src/main/render-ocr-pdf.ts b/src/main/render-ocr-pdf.ts
index d8b14914..42db523a 100644
--- a/src/main/render-ocr-pdf.ts
+++ b/src/main/render-ocr-pdf.ts
@@ -1,4 +1,4 @@
-import { createCanvas } from '@napi-rs/canvas'
+// @napi-rs/canvas is a native module (~85 ms to load); load it on first OCR render (P6).
 
 export async function* renderOcrPdf(
   buffer: Buffer,
@@ -6,7 +6,10 @@ export async function* renderOcrPdf(
   signal?: AbortSignal
 ): AsyncGenerator<{ pageNumber: number; data: Buffer; width: number; height: number }> {
   signal?.throwIfAborted()
-  const { getDocument } = await import('pdfjs-dist/legacy/build/pdf.mjs')
+  const [{ getDocument }, { createCanvas }] = await Promise.all([
+    import('pdfjs-dist/legacy/build/pdf.mjs'),
+    import('@napi-rs/canvas')
+  ])
   const task = getDocument({
     data: Uint8Array.from(buffer), disableFontFace: true,
     isOffscreenCanvasSupported: false, useSystemFonts: false, useWorkerFetch: false
diff --git a/src/main/ssh/ssh-connection-pool.ts b/src/main/ssh/ssh-connection-pool.ts
index 85f8af56..3363d7ce 100644
--- a/src/main/ssh/ssh-connection-pool.ts
+++ b/src/main/ssh/ssh-connection-pool.ts
@@ -1,7 +1,7 @@
 import { createHmac, getCiphers, randomBytes } from "node:crypto";
 import { connect as connectLoopback, type Socket } from "node:net";
-import { Client } from "ssh2";
-import type { ClientChannel, ConnectConfig, SFTPWrapper } from "ssh2";
+import type { Client, ClientChannel, ConnectConfig, SFTPWrapper } from "ssh2";
+import { loadSsh2 } from "./ssh2-module";
 import {
   BoundedStagedSftp,
   type BoundedSftpLimits,
@@ -344,7 +344,7 @@ export class Ssh2AuthenticatedConnection implements AuthenticatedSshConnection {
     validatePoolTarget(target);
     validateConnectionIdentity(target, identity);
     const resolvedDependencies: SshConnectionDependencies = {
-      createClient: () => new Client(),
+      createClient: () => new (loadSsh2().Client)(),
       supportedOpenSslCiphers: getCiphers,
       systemAgent: defaultSystemAgent,
       controlPlanePackageInstaller: Buffer.alloc(0),
diff --git a/src/main/ssh/ssh-transport.ts b/src/main/ssh/ssh-transport.ts
index dd1947a2..bd26f198 100644
--- a/src/main/ssh/ssh-transport.ts
+++ b/src/main/ssh/ssh-transport.ts
@@ -1,11 +1,12 @@
 import { createHash, getCiphers } from 'node:crypto'
-import {
+import type {
   Client,
-  type Algorithms,
-  type CipherAlgorithm,
-  type ConnectConfig,
-  type ServerHostKeyAlgorithm
+  Algorithms,
+  CipherAlgorithm,
+  ConnectConfig,
+  ServerHostKeyAlgorithm
 } from 'ssh2'
+import { loadSsh2 } from './ssh2-module'
 import type {
   SshHostConnectionTestResult
 } from '../../shared/ssh-host-contracts'
@@ -336,7 +337,7 @@ export class Ssh2Transport implements SshTransport {
     dependencies: Partial<SshTransportDependencies> = {}
   ) {
     this.dependencies = {
-      createClient: () => new Client(),
+      createClient: () => new (loadSsh2().Client)(),
       now: Date.now,
       supportedOpenSslCiphers: getCiphers,
       systemAgent: defaultSystemAgent,
diff --git a/src/main/ssh/ssh2-module.ts b/src/main/ssh/ssh2-module.ts
new file mode 100644
index 00000000..ab3bd7a8
--- /dev/null
+++ b/src/main/ssh/ssh2-module.ts
@@ -0,0 +1,8 @@
+import { createLazyRequire } from '../lazy-require'
+
+/**
+ * Loads ssh2 on the first SSH connection instead of at Main startup (P6):
+ * evaluating it costs ~65 ms and most sessions never open a remote host.
+ * Synchronous so existing client factories keep their signatures.
+ */
+export const loadSsh2 = createLazyRequire<typeof import('ssh2')>('ssh2')
diff --git a/src/main/terminal/local-terminal-session.ts b/src/main/terminal/local-terminal-session.ts
index e7c775fa..30eaa969 100644
--- a/src/main/terminal/local-terminal-session.ts
+++ b/src/main/terminal/local-terminal-session.ts
@@ -3,7 +3,7 @@ import { constants as fileSystemConstants } from 'node:fs'
 import { access, stat } from 'node:fs/promises'
 import { homedir } from 'node:os'
 import { posix, win32 } from 'node:path'
-import * as nodePty from 'node-pty'
+import type * as nodePty from 'node-pty'
 import type { IDisposable, IPty } from 'node-pty'
 import {
   TERMINAL_LIMITS,
@@ -393,7 +393,9 @@ export class LocalTerminalSession {
           : undefined,
         this.dependencies
       )
-      const spawn = this.dependencies.spawn ?? nodePty.spawn
+      // node-pty is native; load it when the first terminal starts (P6).
+      const spawn = this.dependencies.spawn ??
+        (await import('node-pty')).spawn
       this.pty = spawn(this.launch.shell, spec?.args ?? [], {
         name: 'xterm-256color',
         cols: this.size.cols,