diff --git a/packages/cli/src/commands/agent/archive.ts b/packages/cli/src/commands/agent/archive.ts
index 0a857c748..b439b6049 100644
--- a/packages/cli/src/commands/agent/archive.ts
+++ b/packages/cli/src/commands/agent/archive.ts
@@ -83,7 +83,8 @@ export async function runArchiveCommand(
       const error: CommandError = {
         code: 'AGENT_RUNNING',
         message: `Agent ${agentId.slice(0, 7)} is currently running`,
-        details: 'Use --force to archive a running agent, or stop it first with: paseo agent stop',
+        details:
+          'Use --force to archive a running agent (it will interrupt the active run), or stop it first with: paseo agent stop',
       }
       throw error
     }
diff --git a/packages/cli/src/commands/agent/index.ts b/packages/cli/src/commands/agent/index.ts
index 4004e2911..c87a0a0db 100644
--- a/packages/cli/src/commands/agent/index.ts
+++ b/packages/cli/src/commands/agent/index.ts
@@ -117,7 +117,7 @@ export function createAgentCommand(): Command {
     .command('archive')
     .description('Archive an agent (soft-delete)')
     .argument('<id>', 'Agent ID (or prefix)')
-    .option('--force', 'Force archive running agent')
+    .option('--force', 'Force archive running agent (interrupts active run first)')
     .option('--json', 'Output in JSON format')
     .option('--host <host>', 'Daemon host:port (default: localhost:6767)')
     .action(withOutput(runArchiveCommand))
diff --git a/packages/server/src/server/daemon-client.e2e.test.ts b/packages/server/src/server/daemon-client.e2e.test.ts
index fbce2eee4..b0a2ff0e0 100644
--- a/packages/server/src/server/daemon-client.e2e.test.ts
+++ b/packages/server/src/server/daemon-client.e2e.test.ts
@@ -196,6 +196,64 @@ describe("daemon client E2E", () => {
     await expect(ctx.client.archiveAgent(randomUUID())).rejects.toThrow();
   }, 10000);
 
+  test("interrupts a running agent before archiving", async () => {
+    const cwd = tmpCwd();
+    try {
+      const created = await ctx.client.createAgent({
+        config: {
+          ...getFullAccessConfig("codex"),
+          cwd,
+        },
+      });
+
+      await ctx.client.sendMessage(
+        created.id,
+        "Use your shell tool to run `sleep 30` and then confirm when done."
+      );
+      await ctx.client.waitForAgentUpsert(
+        created.id,
+        (snapshot) => snapshot.status === "running",
+        15000
+      );
+
+      const result = await ctx.client.archiveAgent(created.id);
+      expect(result.archivedAt).toBeTruthy();
+
+      const archived = await ctx.client.fetchAgent(created.id);
+      expect(archived).not.toBeNull();
+      expect(archived?.archivedAt).toBeTruthy();
+      expect(archived?.status).not.toBe("running");
+
+      const runningAgents = await ctx.client.fetchAgents({
+        filter: { includeArchived: true, statuses: ["running"] },
+      });
+      expect(
+        runningAgents.entries.some((entry) => entry.agent.id === created.id)
+      ).toBe(false);
+    } finally {
+      rmSync(cwd, { recursive: true, force: true });
+    }
+  }, 60000);
+
+  test("rejects send_agent_message for archived agents", async () => {
+    const cwd = tmpCwd();
+    try {
+      const created = await ctx.client.createAgent({
+        config: {
+          ...getFullAccessConfig("codex"),
+          cwd,
+        },
+      });
+
+      await ctx.client.archiveAgent(created.id);
+      await expect(
+        ctx.client.sendMessage(created.id, "Say hello and nothing else")
+      ).rejects.toThrow("archived");
+    } finally {
+      rmSync(cwd, { recursive: true, force: true });
+    }
+  }, 30000);
+
   test("returns home-scoped directory suggestions", async () => {
     const insideHomeDir = mkdtempSync(path.join(homedir(), "paseo-dir-suggestion-"));
     const outsideHomeDir = mkdtempSync(path.join(tmpdir(), "paseo-dir-suggestion-outside-"));
diff --git a/packages/server/src/server/session.ts b/packages/server/src/server/session.ts
index 63e0bd0f5..c87f48090 100644
--- a/packages/server/src/server/session.ts
+++ b/packages/server/src/server/session.ts
@@ -1674,6 +1674,10 @@ export class Session {
   private async handleArchiveAgentRequest(agentId: string, requestId: string): Promise<void> {
     this.sessionLogger.info({ agentId }, `Archiving agent ${agentId}`)
 
+    if (this.agentManager.getAgent(agentId)) {
+      await this.interruptAgentIfRunning(agentId)
+    }
+
     const archivedAt = new Date().toISOString()
 
     const existing = await this.agentStorage.get(agentId)
@@ -1717,6 +1721,11 @@ export class Session {
     })
   }
 
+  private async getArchivedAt(agentId: string): Promise<string | null> {
+    const record = await this.agentStorage.get(agentId)
+    return record?.archivedAt ?? null
+  }
+
   private async handleUpdateAgentRequest(
     agentId: string,
     name: string | undefined,
@@ -2308,6 +2317,16 @@ export class Session {
       return
     }
 
+    const archivedAt = await this.getArchivedAt(agentId)
+    if (archivedAt) {
+      this.handleAgentRunError(
+        agentId,
+        new Error(`Agent ${agentId} is archived`),
+        'Refusing to send prompt to archived agent'
+      )
+      return
+    }
+
     try {
       await this.interruptAgentIfRunning(agentId)
     } catch (error) {
@@ -5250,6 +5269,20 @@ export class Session {
     try {
       const agentId = resolved.agentId
 
+      const archivedAt = await this.getArchivedAt(agentId)
+      if (archivedAt) {
+        this.emit({
+          type: 'send_agent_message_response',
+          payload: {
+            requestId: msg.requestId,
+            agentId,
+            accepted: false,
+            error: `Agent ${agentId} is archived`,
+          },
+        })
+        return
+      }
+
       await this.ensureAgentLoaded(agentId)
       await this.interruptAgentIfRunning(agentId)