feat(cli): add agent stop command

Implements the `agent stop` command for stopping agents.

Features:
- Stop a specific agent by ID (with prefix matching)
- --all flag to stop all running agents
- --cwd flag to stop all agents in a specific directory
- Cancels running agents before terminating them
- Graceful error handling for partially failed stops

Usage:
  paseo agent stop <id>
  paseo agent stop --all
  paseo agent stop --cwd ~/dev/paseo

packages/cli/src/commands/agent/stop.ts

@@ -0,0 +1,131 @@
+import type { Command } from 'commander'
+import { connectToDaemon, getDaemonHost, resolveAgentId } from '../../utils/client.js'
+import type { CommandOptions, SingleResult, OutputSchema, CommandError } from '../../output/index.js'
+
+/** Result type for agent stop command */
+export interface StopResult {
+  stoppedCount: number
+  agentIds: string[]
+}
+
+/** Schema for stop command output */
+export const stopSchema: OutputSchema<StopResult> = {
+  // For quiet mode, output the stopped agent IDs (one per line)
+  idField: (item) => item.agentIds.join('\n'),
+  columns: [{ header: 'STOPPED', field: 'stoppedCount' }],
+}
+
+export interface AgentStopOptions extends CommandOptions {
+  all?: boolean
+  cwd?: string
+}
+
+export type AgentStopResult = SingleResult<StopResult>
+
+export async function runStopCommand(
+  id: string | undefined,
+  options: AgentStopOptions,
+  _command: Command
+): Promise<AgentStopResult> {
+  const host = getDaemonHost({ host: options.host as string | undefined })
+
+  // Validate arguments - need either an id, --all, or --cwd
+  if (!id && !options.all && !options.cwd) {
+    const error: CommandError = {
+      code: 'MISSING_ARGUMENT',
+      message: 'Agent ID required unless --all or --cwd is specified',
+      details: 'Usage: paseo agent stop <id> | --all | --cwd <path>',
+    }
+    throw error
+  }
+
+  let client
+  try {
+    client = await connectToDaemon({ host: options.host as string | undefined })
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    const error: CommandError = {
+      code: 'DAEMON_NOT_RUNNING',
+      message: `Cannot connect to daemon at ${host}: ${message}`,
+      details: 'Start the daemon with: paseo daemon start',
+    }
+    throw error
+  }
+
+  try {
+    // Request session state to get agent information
+    client.requestSessionState()
+
+    // Wait a moment for the session state to be populated
+    await new Promise((resolve) => setTimeout(resolve, 500))
+
+    let agents = client.listAgents()
+    const stoppedIds: string[] = []
+
+    if (options.all) {
+      // Stop all agents (not archived)
+      agents = agents.filter((a) => !a.archivedAt)
+    } else if (options.cwd) {
+      // Stop agents in directory
+      const filterCwd = options.cwd
+      agents = agents.filter((a) => {
+        if (a.archivedAt) return false
+        const agentCwd = a.cwd.replace(/\/$/, '')
+        const targetCwd = filterCwd.replace(/\/$/, '')
+        return agentCwd === targetCwd || agentCwd.startsWith(targetCwd + '/')
+      })
+    } else if (id) {
+      // Stop specific agent
+      const resolvedId = resolveAgentId(id, agents)
+      if (!resolvedId) {
+        const error: CommandError = {
+          code: 'AGENT_NOT_FOUND',
+          message: `No agent found matching: ${id}`,
+          details: 'Use `paseo agent ps` to list available agents',
+        }
+        throw error
+      }
+      agents = agents.filter((a) => a.id === resolvedId)
+    }
+
+    // Stop each agent
+    for (const agent of agents) {
+      try {
+        // Cancel if running
+        if (agent.status === 'running') {
+          await client.cancelAgent(agent.id)
+        }
+        // Delete the agent
+        await client.deleteAgent(agent.id)
+        stoppedIds.push(agent.id)
+      } catch (err) {
+        // Continue stopping other agents even if one fails
+        const message = err instanceof Error ? err.message : String(err)
+        console.error(`Warning: Failed to stop agent ${agent.id.slice(0, 7)}: ${message}`)
+      }
+    }
+
+    await client.close()
+
+    return {
+      type: 'single',
+      data: {
+        stoppedCount: stoppedIds.length,
+        agentIds: stoppedIds,
+      },
+      schema: stopSchema,
+    }
+  } catch (err) {
+    await client.close().catch(() => {})
+    // Re-throw if it's already a CommandError
+    if (err && typeof err === 'object' && 'code' in err) {
+      throw err
+    }
+    const message = err instanceof Error ? err.message : String(err)
+    const error: CommandError = {
+      code: 'STOP_AGENT_FAILED',
+      message: `Failed to stop agent(s): ${message}`,
+    }
+    throw error
+  }
+}

packages/cli/tests/07-agent-stop.test.mts

@@ -0,0 +1,136 @@
+#!/usr/bin/env npx tsx
+
+/**
+ * Phase 6: Agent Stop Command Tests
+ *
+ * Tests the agent stop command - stopping agents (cancel if running, then terminate).
+ * Since daemon may not be running, we test both:
+ * - Help and argument parsing
+ * - Graceful error handling when daemon not running
+ * - All flags are accepted
+ *
+ * Tests:
+ * - agent stop --help shows options
+ * - agent stop requires ID, --all, or --cwd
+ * - agent stop handles daemon not running
+ * - agent stop --all flag is accepted
+ * - agent stop --cwd flag is accepted
+ */
+
+import assert from 'node:assert'
+import { $ } from 'zx'
+import { mkdtemp, rm } from 'fs/promises'
+import { tmpdir } from 'os'
+import { join } from 'path'
+
+$.verbose = false
+
+console.log('=== Agent Stop Command Tests ===\n')
+
+// Get random port that's definitely not in use (never 6767)
+const port = 10000 + Math.floor(Math.random() * 50000)
+const paseoHome = await mkdtemp(join(tmpdir(), 'paseo-test-home-'))
+
+try {
+  // Test 1: agent stop --help shows options
+  {
+    console.log('Test 1: agent stop --help shows options')
+    const result = await $`npx paseo agent stop --help`.nothrow()
+    assert.strictEqual(result.exitCode, 0, 'agent stop --help should exit 0')
+    assert(result.stdout.includes('--all'), 'help should mention --all flag')
+    assert(result.stdout.includes('--cwd'), 'help should mention --cwd option')
+    assert(result.stdout.includes('--host'), 'help should mention --host option')
+    assert(result.stdout.includes('[id]'), 'help should mention optional id argument')
+    console.log('✓ agent stop --help shows options\n')
+  }
+
+  // Test 2: agent stop requires ID, --all, or --cwd
+  {
+    console.log('Test 2: agent stop requires ID, --all, or --cwd')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop`.nothrow()
+    assert.notStrictEqual(result.exitCode, 0, 'should fail without id, --all, or --cwd')
+    const output = result.stdout + result.stderr
+    const hasError =
+      output.toLowerCase().includes('missing') ||
+      output.toLowerCase().includes('required') ||
+      output.toLowerCase().includes('argument') ||
+      output.toLowerCase().includes('id')
+    assert(hasError, 'error should mention missing argument')
+    console.log('✓ agent stop requires ID, --all, or --cwd\n')
+  }
+
+  // Test 3: agent stop handles daemon not running
+  {
+    console.log('Test 3: agent stop handles daemon not running')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop abc123`.nothrow()
+    // Should fail because daemon not running
+    assert.notStrictEqual(result.exitCode, 0, 'should fail when daemon not running')
+    const output = result.stdout + result.stderr
+    const hasError =
+      output.toLowerCase().includes('daemon') ||
+      output.toLowerCase().includes('connect') ||
+      output.toLowerCase().includes('cannot')
+    assert(hasError, 'error message should mention connection issue')
+    console.log('✓ agent stop handles daemon not running\n')
+  }
+
+  // Test 4: agent stop --all flag is accepted
+  {
+    console.log('Test 4: agent stop --all flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop --all`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --all flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop --all flag is accepted\n')
+  }
+
+  // Test 5: agent stop --cwd flag is accepted
+  {
+    console.log('Test 5: agent stop --cwd flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop --cwd /tmp`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --cwd flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop --cwd flag is accepted\n')
+  }
+
+  // Test 6: agent stop with ID and --host flag is accepted
+  {
+    console.log('Test 6: agent stop with ID and --host flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop abc123 --host localhost:${port}`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --host flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop with ID and --host flag is accepted\n')
+  }
+
+  // Test 7: agent shows stop in subcommands
+  {
+    console.log('Test 7: agent --help shows stop subcommand')
+    const result = await $`npx paseo agent --help`.nothrow()
+    assert.strictEqual(result.exitCode, 0, 'agent --help should exit 0')
+    assert(result.stdout.includes('stop'), 'help should mention stop subcommand')
+    console.log('✓ agent --help shows stop subcommand\n')
+  }
+
+  // Test 8: -q (quiet) flag is accepted with agent stop
+  {
+    console.log('Test 8: -q (quiet) flag is accepted with agent stop')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo -q agent stop abc123`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept -q flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ -q (quiet) flag is accepted with agent stop\n')
+  }
+} finally {
+  // Clean up temp directory
+  await rm(paseoHome, { recursive: true, force: true })
+}
+
+console.log('=== All agent stop tests passed ===')