diff --git a/src/main/core/agent-hooks/agent-hook-service.ts b/src/main/core/agent-hooks/agent-hook-service.ts
index dd5ac8b93..53b9fae45 100644
--- a/src/main/core/agent-hooks/agent-hook-service.ts
+++ b/src/main/core/agent-hooks/agent-hook-service.ts
@@ -6,6 +6,7 @@ import { telemetryService } from '@main/lib/telemetry';
 import { agentEventChannel, type AgentEvent } from '@shared/events/agentEvents';
 import { conversationChangedChannel } from '@shared/events/conversationEvents';
 import { enrichEvent } from './event-enricher';
+import { handleProviderSessionHook } from './handle-provider-session-hook';
 import { HookServer } from './hook-server';
 import { isAppFocused, maybeShowNotification } from './notification';
 
@@ -14,6 +15,11 @@ class AgentHookService implements IInitializable, IDisposable {
 
   async initialize(): Promise<void> {
     await this.server.start(async (raw) => {
+      if (raw.type === 'session') {
+        await handleProviderSessionHook(raw);
+        return;
+      }
+
       const event = await enrichEvent(raw);
       event.source = 'hook';
       const appFocused = isAppFocused();
diff --git a/src/main/core/agent-hooks/agent-notify-command.test.ts b/src/main/core/agent-hooks/agent-notify-command.test.ts
index f78d8e375..e02e85530 100644
--- a/src/main/core/agent-hooks/agent-notify-command.test.ts
+++ b/src/main/core/agent-hooks/agent-notify-command.test.ts
@@ -66,6 +66,9 @@ describe('makeOpenCodePluginContent', () => {
     const content = makeOpenCodePluginContent();
 
     expect(content).toContain('EMDASH_HOOK_PORT');
+    expect(content).toContain("event.type === 'session.created'");
+    expect(content).toContain('event.properties?.info?.parentID');
+    expect(content).toContain('event.properties?.info?.id');
     expect(content).toContain("event.type === 'session.idle'");
     expect(content).toContain("event.type === 'session.error'");
     expect(content).toContain("'X-Emdash-Event-Type': payload.type");
diff --git a/src/main/core/agent-hooks/handle-provider-session-hook.ts b/src/main/core/agent-hooks/handle-provider-session-hook.ts
new file mode 100644
index 000000000..a22df6f99
--- /dev/null
+++ b/src/main/core/agent-hooks/handle-provider-session-hook.ts
@@ -0,0 +1,27 @@
+import { saveProviderSessionId } from '@main/core/conversations/save-provider-session-id';
+import { log } from '@main/lib/logger';
+import { parsePtyId } from '@shared/ptyId';
+import type { RawHookRequest } from './hook-server';
+
+export async function handleProviderSessionHook(raw: RawHookRequest): Promise<void> {
+  const parsed = parsePtyId(raw.ptyId);
+  if (!parsed || parsed.providerId !== 'opencode') return;
+
+  let body: Record<string, unknown> = {};
+  if (raw.body) {
+    try {
+      const value: unknown = JSON.parse(raw.body);
+      if (typeof value === 'object' && value !== null) {
+        body = value as Record<string, unknown>;
+      }
+    } catch {
+      log.warn('handleProviderSessionHook: invalid JSON body', { ptyId: raw.ptyId });
+      return;
+    }
+  }
+
+  const providerSessionId = body.provider_session_id ?? body.providerSessionId;
+  if (typeof providerSessionId !== 'string' || providerSessionId.length === 0) return;
+
+  await saveProviderSessionId(parsed.conversationId, providerSessionId);
+}
diff --git a/src/main/core/agent-hooks/opencode-notifications-plugin.js b/src/main/core/agent-hooks/opencode-notifications-plugin.js
index c1315f6f6..c779bfa12 100644
--- a/src/main/core/agent-hooks/opencode-notifications-plugin.js
+++ b/src/main/core/agent-hooks/opencode-notifications-plugin.js
@@ -28,6 +28,18 @@ export const EmdashNotifications = async () => ({
 });
 
 function toEmdashPayload(event) {
+  if (event.type === 'session.created') {
+    if (event.properties?.info?.parentID) return;
+    const sessionID = event.properties?.info?.id;
+    if (typeof sessionID !== 'string' || sessionID.length === 0) return;
+    return {
+      type: 'session',
+      body: {
+        provider_session_id: sessionID,
+      },
+    };
+  }
+
   if (event.type === 'session.idle') {
     return {
       type: 'notification',
diff --git a/src/main/core/conversations/createConversation.ts b/src/main/core/conversations/createConversation.ts
index 6c37e34af..c1865dd7f 100644
--- a/src/main/core/conversations/createConversation.ts
+++ b/src/main/core/conversations/createConversation.ts
@@ -5,6 +5,7 @@ import { db } from '@main/db/client';
 import { conversations } from '@main/db/schema';
 import { log } from '@main/lib/logger';
 import { telemetryService } from '@main/lib/telemetry';
+import { serializeConversationConfig } from '@shared/conversation-config';
 import { type Conversation, type CreateConversationParams } from '@shared/conversations';
 import { resolveTask } from '../projects/utils';
 import { conversationEvents } from './conversation-events';
@@ -21,7 +22,7 @@ export async function createConversation(params: CreateConversationParams): Prom
   const config =
     params.autoApprove === undefined
       ? undefined
-      : JSON.stringify({ autoApprove: params.autoApprove });
+      : serializeConversationConfig({ autoApprove: params.autoApprove });
 
   const [row] = await db
     .insert(conversations)
diff --git a/src/main/core/conversations/impl/agent-command.test.ts b/src/main/core/conversations/impl/agent-command.test.ts
index 53c8eb2bb..015ac88ac 100644
--- a/src/main/core/conversations/impl/agent-command.test.ts
+++ b/src/main/core/conversations/impl/agent-command.test.ts
@@ -169,7 +169,7 @@ describe('buildAgentCommand', () => {
     {
       providerId: 'opencode',
       freshArgs: ['--prompt', 'Fix the bug'],
-      resumeArgs: ['--continue'],
+      resumeArgs: ['--session', 'conv-1'],
     },
     { providerId: 'grok', freshArgs: [], resumeArgs: ['-r'] },
     { providerId: 'copilot', freshArgs: ['Fix the bug'], resumeArgs: ['--resume'] },
diff --git a/src/main/core/conversations/impl/local-conversation.ts b/src/main/core/conversations/impl/local-conversation.ts
index 53e7b6730..784633b48 100644
--- a/src/main/core/conversations/impl/local-conversation.ts
+++ b/src/main/core/conversations/impl/local-conversation.ts
@@ -22,6 +22,7 @@ import type { Conversation } from '@shared/conversations';
 import { agentSessionExitedChannel } from '@shared/events/agentEvents';
 import { makePtyId } from '@shared/ptyId';
 import { makePtySessionId } from '@shared/ptySessionId';
+import { resolveAgentSessionCommandArgs } from '../resolve-agent-session-command';
 import { buildAgentSessionCommand } from './agent-command';
 import { scheduleInitialPromptInjection } from './keystroke-injection';
 import { resolveProviderEnv } from './provider-env';
@@ -97,12 +98,13 @@ export class LocalConversationProvider implements ConversationProvider {
 
     const providerConfig = await providerOverrideSettings.getItem(conversation.providerId);
     const providerDef = getProvider(conversation.providerId);
+    const agentSession = resolveAgentSessionCommandArgs(conversation, isResuming);
     const { command, args } = buildAgentSessionCommand({
       providerId: conversation.providerId,
       providerConfig,
       autoApprove: conversation.autoApprove,
-      sessionId: conversation.id,
-      isResuming,
+      sessionId: agentSession.sessionId,
+      isResuming: agentSession.isResuming,
       initialPrompt,
     });
     const providerEnv = resolveProviderEnv(providerConfig, {
diff --git a/src/main/core/conversations/impl/ssh-conversation.ts b/src/main/core/conversations/impl/ssh-conversation.ts
index 492e71d5a..e25415039 100644
--- a/src/main/core/conversations/impl/ssh-conversation.ts
+++ b/src/main/core/conversations/impl/ssh-conversation.ts
@@ -17,6 +17,7 @@ import type { AgentSessionConfig } from '@shared/agent-session';
 import type { Conversation } from '@shared/conversations';
 import { agentSessionExitedChannel } from '@shared/events/agentEvents';
 import { makePtySessionId } from '@shared/ptySessionId';
+import { resolveAgentSessionCommandArgs } from '../resolve-agent-session-command';
 import { buildAgentSessionCommand } from './agent-command';
 import { scheduleInitialPromptInjection } from './keystroke-injection';
 import { resolveProviderEnv } from './provider-env';
@@ -90,12 +91,13 @@ export class SshConversationProvider implements ConversationProvider {
     });
 
     const providerConfig = await providerOverrideSettings.getItem(conversation.providerId);
+    const agentSession = resolveAgentSessionCommandArgs(conversation, isResuming);
     const { command, args } = buildAgentSessionCommand({
       providerId: conversation.providerId,
       providerConfig,
       autoApprove: conversation.autoApprove,
-      sessionId: conversation.id,
-      isResuming,
+      sessionId: agentSession.sessionId,
+      isResuming: agentSession.isResuming,
       initialPrompt,
     });
     const providerEnv = resolveProviderEnv(providerConfig, {
@@ -115,7 +117,7 @@ export class SshConversationProvider implements ConversationProvider {
       shellSetup: this.shellSetup,
       tmuxSessionName,
       autoApprove: conversation.autoApprove ?? false,
-      resume: isResuming,
+      resume: agentSession.isResuming,
     };
 
     const profile = await this.proxy.getRemoteShellProfile();
diff --git a/src/main/core/conversations/resolve-agent-session-command.test.ts b/src/main/core/conversations/resolve-agent-session-command.test.ts
new file mode 100644
index 000000000..0178356fc
--- /dev/null
+++ b/src/main/core/conversations/resolve-agent-session-command.test.ts
@@ -0,0 +1,40 @@
+import { describe, expect, it } from 'vitest';
+import type { Conversation } from '@shared/conversations';
+import { resolveAgentSessionCommandArgs } from './resolve-agent-session-command';
+
+function makeConversation(overrides: Partial<Conversation> = {}): Conversation {
+  return {
+    id: 'conv-1',
+    projectId: 'proj-1',
+    taskId: 'task-1',
+    providerId: 'opencode',
+    title: 'Test',
+    lastInteractedAt: null,
+    isInitialConversation: false,
+    ...overrides,
+  };
+}
+
+describe('resolveAgentSessionCommandArgs', () => {
+  it('uses stored OpenCode session id when resuming', () => {
+    expect(
+      resolveAgentSessionCommandArgs(makeConversation({ providerSessionId: 'ses_abc123' }), true)
+    ).toEqual({ sessionId: 'ses_abc123', isResuming: true });
+  });
+
+  it('starts fresh when resuming OpenCode without a stored session id', () => {
+    expect(resolveAgentSessionCommandArgs(makeConversation(), true)).toEqual({
+      sessionId: 'conv-1',
+      isResuming: false,
+    });
+  });
+
+  it('passes through for non-OpenCode providers', () => {
+    expect(
+      resolveAgentSessionCommandArgs(
+        makeConversation({ providerId: 'claude', providerSessionId: 'ses_ignored' }),
+        true
+      )
+    ).toEqual({ sessionId: 'conv-1', isResuming: true });
+  });
+});
diff --git a/src/main/core/conversations/resolve-agent-session-command.ts b/src/main/core/conversations/resolve-agent-session-command.ts
new file mode 100644
index 000000000..234d92125
--- /dev/null
+++ b/src/main/core/conversations/resolve-agent-session-command.ts
@@ -0,0 +1,22 @@
+import { log } from '@main/lib/logger';
+import type { Conversation } from '@shared/conversations';
+
+/** OpenCode `--continue` resumes the last global session, not per Emdash chat. */
+export function resolveAgentSessionCommandArgs(
+  conversation: Conversation,
+  isResuming: boolean
+): { sessionId: string; isResuming: boolean } {
+  if (conversation.providerId === 'opencode' && isResuming) {
+    if (conversation.providerSessionId) {
+      return { sessionId: conversation.providerSessionId, isResuming: true };
+    }
+    log.warn('resolveAgentSessionCommandArgs: OpenCode resume skipped — no providerSessionId', {
+      conversationId: conversation.id,
+      taskId: conversation.taskId,
+      projectId: conversation.projectId,
+    });
+    return { sessionId: conversation.id, isResuming: false };
+  }
+
+  return { sessionId: conversation.id, isResuming };
+}
diff --git a/src/main/core/conversations/save-provider-session-id.ts b/src/main/core/conversations/save-provider-session-id.ts
new file mode 100644
index 000000000..b6d0a46f8
--- /dev/null
+++ b/src/main/core/conversations/save-provider-session-id.ts
@@ -0,0 +1,56 @@
+import { eq } from 'drizzle-orm';
+import { db } from '@main/db/client';
+import { conversations } from '@main/db/schema';
+import { events } from '@main/lib/events';
+import { log } from '@main/lib/logger';
+import {
+  isOpenCodeProviderSessionId,
+  parseConversationConfig,
+  serializeConversationConfig,
+} from '@shared/conversation-config';
+import { conversationChangedChannel } from '@shared/events/conversationEvents';
+
+export async function saveProviderSessionId(
+  conversationId: string,
+  providerSessionId: string
+): Promise<void> {
+  if (!isOpenCodeProviderSessionId(providerSessionId)) {
+    log.warn('saveProviderSessionId: ignored invalid OpenCode session id', {
+      conversationId,
+      providerSessionId,
+    });
+    return;
+  }
+
+  const [row] = await db
+    .select({
+      config: conversations.config,
+      projectId: conversations.projectId,
+      taskId: conversations.taskId,
+    })
+    .from(conversations)
+    .where(eq(conversations.id, conversationId))
+    .limit(1);
+
+  if (!row) return;
+
+  const config = parseConversationConfig(row.config);
+  if (config.providerSessionId === providerSessionId) return;
+
+  const nextConfig = serializeConversationConfig({
+    ...config,
+    providerSessionId,
+  });
+
+  await db
+    .update(conversations)
+    .set({ config: nextConfig, updatedAt: new Date().toISOString() })
+    .where(eq(conversations.id, conversationId));
+
+  events.emit(conversationChangedChannel, {
+    conversationId,
+    taskId: row.taskId,
+    projectId: row.projectId,
+    changes: { providerSessionId },
+  });
+}
diff --git a/src/main/core/conversations/utils.ts b/src/main/core/conversations/utils.ts
index 7296ae4bb..df07e9ba4 100644
--- a/src/main/core/conversations/utils.ts
+++ b/src/main/core/conversations/utils.ts
@@ -1,18 +1,21 @@
 import { type ConversationRow } from '@main/db/schema';
 import { type AgentProviderId } from '@shared/agent-provider-registry';
+import { parseConversationConfig } from '@shared/conversation-config';
 import { type Conversation } from '@shared/conversations';
 
 export function mapConversationRowToConversation(
   row: ConversationRow,
   resume: boolean = false
 ): Conversation {
+  const config = parseConversationConfig(row.config);
   return {
     id: row.id,
     title: row.title,
     taskId: row.taskId,
     projectId: row.projectId,
     providerId: row.provider as AgentProviderId,
-    autoApprove: row.config ? JSON.parse(row.config).autoApprove : undefined,
+    autoApprove: config.autoApprove,
+    providerSessionId: config.providerSessionId,
     resume: resume,
     lastInteractedAt: row.lastInteractedAt ?? null,
     isInitialConversation: row.isInitialConversation,
diff --git a/src/shared/agent-provider-registry.ts b/src/shared/agent-provider-registry.ts
index 329440b92..91b5e79bf 100644
--- a/src/shared/agent-provider-registry.ts
+++ b/src/shared/agent-provider-registry.ts
@@ -270,7 +270,9 @@ export const AGENT_PROVIDERS: AgentProviderDefinition[] = [
     versionArgs: ['--version'],
     cli: 'opencode',
     initialPromptFlag: '--prompt',
-    resumeFlag: '--continue',
+    resumeFlag: '--session',
+    sessionIdFlag: '--session',
+    sessionIdOnResumeOnly: true,
     icon: 'opencode.png',
     alt: 'OpenCode CLI',
     invertInDark: true,
diff --git a/src/shared/conversation-config.test.ts b/src/shared/conversation-config.test.ts
new file mode 100644
index 000000000..34f320341
--- /dev/null
+++ b/src/shared/conversation-config.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, it } from 'vitest';
+import {
+  isOpenCodeProviderSessionId,
+  parseConversationConfig,
+  serializeConversationConfig,
+} from './conversation-config';
+
+describe('parseConversationConfig', () => {
+  it('parses autoApprove and providerSessionId', () => {
+    expect(
+      parseConversationConfig(JSON.stringify({ autoApprove: true, providerSessionId: 'ses_abc' }))
+    ).toEqual({ autoApprove: true, providerSessionId: 'ses_abc' });
+  });
+
+  it('returns empty config for invalid JSON', () => {
+    expect(parseConversationConfig('not-json')).toEqual({});
+  });
+});
+
+describe('isOpenCodeProviderSessionId', () => {
+  it('accepts OpenCode session ids', () => {
+    expect(isOpenCodeProviderSessionId('ses_0123456789abcdef')).toBe(true);
+  });
+
+  it('rejects non-OpenCode ids', () => {
+    expect(isOpenCodeProviderSessionId('conv-1')).toBe(false);
+    expect(isOpenCodeProviderSessionId('ses_')).toBe(false);
+  });
+});
+
+describe('serializeConversationConfig', () => {
+  it('round-trips known fields', () => {
+    const raw = serializeConversationConfig({
+      autoApprove: false,
+      providerSessionId: 'ses_xyz',
+    });
+    expect(parseConversationConfig(raw)).toEqual({
+      autoApprove: false,
+      providerSessionId: 'ses_xyz',
+    });
+  });
+});
diff --git a/src/shared/conversation-config.ts b/src/shared/conversation-config.ts
new file mode 100644
index 000000000..2a5527860
--- /dev/null
+++ b/src/shared/conversation-config.ts
@@ -0,0 +1,32 @@
+const OPENCODE_SESSION_ID_PATTERN = /^ses_.+/;
+
+export function isOpenCodeProviderSessionId(value: string): boolean {
+  return OPENCODE_SESSION_ID_PATTERN.test(value);
+}
+
+export type ConversationConfig = {
+  autoApprove?: boolean;
+  /** Provider-native session id (e.g. OpenCode `ses_*`) for resuming the correct chat. */
+  providerSessionId?: string;
+};
+
+export function parseConversationConfig(raw: string | null | undefined): ConversationConfig {
+  if (!raw) return {};
+  try {
+    const parsed: unknown = JSON.parse(raw);
+    if (typeof parsed !== 'object' || parsed === null) return {};
+    const record = parsed as Record<string, unknown>;
+    return {
+      ...(typeof record.autoApprove === 'boolean' ? { autoApprove: record.autoApprove } : {}),
+      ...(typeof record.providerSessionId === 'string'
+        ? { providerSessionId: record.providerSessionId }
+        : {}),
+    };
+  } catch {
+    return {};
+  }
+}
+
+export function serializeConversationConfig(config: ConversationConfig): string {
+  return JSON.stringify(config);
+}
diff --git a/src/shared/conversations.ts b/src/shared/conversations.ts
index 840a74e97..5991d282e 100644
--- a/src/shared/conversations.ts
+++ b/src/shared/conversations.ts
@@ -9,6 +9,8 @@ export type Conversation = {
   lastInteractedAt: string | null;
   resume?: boolean;
   autoApprove?: boolean;
+  /** OpenCode `ses_*` id captured from the provider for per-chat resume. */
+  providerSessionId?: string;
   isInitialConversation: boolean | null;
 };
 
diff --git a/src/shared/events/conversationEvents.ts b/src/shared/events/conversationEvents.ts
index 1c9194004..cd7b2279d 100644
--- a/src/shared/events/conversationEvents.ts
+++ b/src/shared/events/conversationEvents.ts
@@ -5,5 +5,5 @@ export const conversationChangedChannel = defineEvent<{
   conversationId: string;
   taskId: string;
   projectId: string;
-  changes: Partial<Pick<Conversation, 'lastInteractedAt' | 'title'>>;
+  changes: Partial<Pick<Conversation, 'lastInteractedAt' | 'title' | 'providerSessionId'>>;
 }>('conversation:changed');