diff --git a/.gitignore b/.gitignore
index 98fe346e..08336315 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,8 +17,9 @@ dist/
 downloads/
 eggs/
 .eggs/
-lib/
-lib64/
+# Root-only: unanchored `lib/` would ignore Next.js `ui/lib/`
+/lib/
+/lib64/
 parts/
 sdist/
 var/
diff --git a/ui/__tests__/lib/api-client.test.ts b/ui/__tests__/lib/api-client.test.ts
new file mode 100644
index 00000000..e0c8dcc7
--- /dev/null
+++ b/ui/__tests__/lib/api-client.test.ts
@@ -0,0 +1,28 @@
+import { createRun, listRuns, getSettings } from '@/lib/api-client'
+
+global.fetch = jest.fn()
+
+beforeEach(() => jest.clearAllMocks())
+
+test('createRun POSTs to /api/runs and returns run summary', async () => {
+  const mockRun = { id: 'abc123', ticker: 'NVDA', status: 'queued' }
+  ;(fetch as jest.Mock).mockResolvedValueOnce({
+    ok: true,
+    json: async () => mockRun,
+  })
+  const result = await createRun({
+    ticker: 'NVDA', date: '2024-05-10',
+    llm_provider: 'openai', deep_think_llm: 'gpt-5.2',
+    quick_think_llm: 'gpt-5-mini', max_debate_rounds: 1,
+    max_risk_discuss_rounds: 1,
+  })
+  expect(fetch).toHaveBeenCalledWith('/api/runs', expect.objectContaining({ method: 'POST' }))
+  expect(result.id).toBe('abc123')
+})
+
+test('listRuns GETs /api/runs', async () => {
+  ;(fetch as jest.Mock).mockResolvedValueOnce({ ok: true, json: async () => [] })
+  const result = await listRuns()
+  expect(fetch).toHaveBeenCalledWith('/api/runs')
+  expect(Array.isArray(result)).toBe(true)
+})
diff --git a/ui/lib/api-client.ts b/ui/lib/api-client.ts
new file mode 100644
index 00000000..b8074e64
--- /dev/null
+++ b/ui/lib/api-client.ts
@@ -0,0 +1,33 @@
+import type { RunConfig, RunSummary } from './types/run'
+import type { Settings } from './types/settings'
+
+const API = process.env.NEXT_PUBLIC_API_URL ?? ''
+
+async function apiFetch<T>(path: string, init?: RequestInit): Promise<T> {
+  const res = init
+    ? await fetch(`${API}${path}`, {
+        headers: { 'Content-Type': 'application/json' },
+        ...init,
+      })
+    : await fetch(`${API}${path}`)
+  if (!res.ok) throw new Error(`API error ${res.status}: ${path}`)
+  return res.json() as Promise<T>
+}
+
+export const createRun = (config: RunConfig): Promise<RunSummary> =>
+  apiFetch('/api/runs', { method: 'POST', body: JSON.stringify(config) })
+
+export const listRuns = (): Promise<RunSummary[]> =>
+  apiFetch('/api/runs')
+
+export const getRun = (id: string): Promise<RunSummary> =>
+  apiFetch(`/api/runs/${id}`)
+
+export const getSettings = (): Promise<Settings> =>
+  apiFetch('/api/settings')
+
+export const updateSettings = (settings: Settings): Promise<Settings> =>
+  apiFetch('/api/settings', { method: 'PUT', body: JSON.stringify(settings) })
+
+export const getRunStreamUrl = (id: string): string =>
+  `${process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:8000'}/api/runs/${id}/stream`
diff --git a/ui/lib/sse.ts b/ui/lib/sse.ts
new file mode 100644
index 00000000..dc700d13
--- /dev/null
+++ b/ui/lib/sse.ts
@@ -0,0 +1,42 @@
+export type SSEHandlers = {
+  onAgentStart?: (data: { step: string; turn: number }) => void
+  onAgentComplete?: (data: { step: string; turn: number; report: string }) => void
+  onRunComplete?: (data: { decision: string; run_id: string }) => void
+  onRunError?: (data: { message: string }) => void
+  onOpen?: () => void
+}
+
+export function createSSEConnection(url: string, handlers: SSEHandlers): () => void {
+  const source = new EventSource(url)
+
+  source.onopen = () => handlers.onOpen?.()
+
+  source.onerror = () => {
+    handlers.onRunError?.({ message: 'SSE connection error' })
+    source.close()
+  }
+
+  source.addEventListener('agent:start', (e: MessageEvent) => {
+    try { handlers.onAgentStart?.(JSON.parse(e.data)) }
+    catch { handlers.onRunError?.({ message: 'Failed to parse event data' }) }
+  })
+
+  source.addEventListener('agent:complete', (e: MessageEvent) => {
+    try { handlers.onAgentComplete?.(JSON.parse(e.data)) }
+    catch { handlers.onRunError?.({ message: 'Failed to parse event data' }) }
+  })
+
+  source.addEventListener('run:complete', (e: MessageEvent) => {
+    try { handlers.onRunComplete?.(JSON.parse(e.data)) }
+    catch { handlers.onRunError?.({ message: 'Failed to parse event data' }) }
+    source.close()
+  })
+
+  source.addEventListener('run:error', (e: MessageEvent) => {
+    try { handlers.onRunError?.(JSON.parse(e.data)) }
+    catch { handlers.onRunError?.({ message: 'Failed to parse event data' }) }
+    source.close()
+  })
+
+  return () => source.close()
+}
diff --git a/ui/lib/types/agents.ts b/ui/lib/types/agents.ts
new file mode 100644
index 00000000..fff402dc
--- /dev/null
+++ b/ui/lib/types/agents.ts
@@ -0,0 +1,6 @@
+import type { AgentStep } from './run'
+
+export type Decision = 'BUY' | 'SELL' | 'HOLD'
+export type DebateTurn = { speaker: string; text: string }
+export type PhaseReport = { step: AgentStep; content: string }
+export type StepStatus = 'pending' | 'running' | 'done'
diff --git a/ui/lib/types/run.ts b/ui/lib/types/run.ts
new file mode 100644
index 00000000..3947976e
--- /dev/null
+++ b/ui/lib/types/run.ts
@@ -0,0 +1,72 @@
+export type AgentStep =
+  | 'market_analyst'
+  | 'news_analyst'
+  | 'fundamentals_analyst'
+  | 'social_analyst'
+  | 'bull_researcher'
+  | 'bear_researcher'
+  | 'research_manager'
+  | 'trader'
+  | 'aggressive_analyst'
+  | 'conservative_analyst'
+  | 'neutral_analyst'
+  | 'risk_judge'
+
+export const AGENT_STEPS: AgentStep[] = [
+  'market_analyst', 'news_analyst', 'fundamentals_analyst', 'social_analyst',
+  'bull_researcher', 'bear_researcher', 'research_manager',
+  'trader',
+  'aggressive_analyst', 'conservative_analyst', 'neutral_analyst', 'risk_judge',
+]
+
+export const AGENT_STEP_LABELS: Record<AgentStep, string> = {
+  market_analyst:       'Market',
+  news_analyst:         'News',
+  fundamentals_analyst: 'Fundamentals',
+  social_analyst:       'Social',
+  bull_researcher:      'Bull Researcher',
+  bear_researcher:      'Bear Researcher',
+  research_manager:     'Research Manager',
+  trader:               'Trader',
+  aggressive_analyst:   'Aggressive',
+  conservative_analyst: 'Conservative',
+  neutral_analyst:      'Neutral',
+  risk_judge:           'Risk Judge',
+}
+
+export const STEP_PHASE: Record<AgentStep, 'analysts' | 'researchers' | 'trader' | 'risk'> = {
+  market_analyst:       'analysts',
+  news_analyst:         'analysts',
+  fundamentals_analyst: 'analysts',
+  social_analyst:       'analysts',
+  bull_researcher:      'researchers',
+  bear_researcher:      'researchers',
+  research_manager:     'researchers',
+  trader:               'trader',
+  aggressive_analyst:   'risk',
+  conservative_analyst: 'risk',
+  neutral_analyst:      'risk',
+  risk_judge:           'risk',
+}
+
+export type RunStatus = 'queued' | 'running' | 'complete' | 'error'
+
+export type RunConfig = {
+  ticker: string
+  date: string
+  llm_provider: string
+  deep_think_llm: string
+  quick_think_llm: string
+  max_debate_rounds: number
+  max_risk_discuss_rounds: number
+  enabled_analysts?: string[]
+}
+
+export type RunSummary = {
+  id: string
+  ticker: string
+  date: string
+  status: RunStatus
+  decision: 'BUY' | 'SELL' | 'HOLD' | null
+  created_at: string
+}
diff --git a/ui/lib/types/settings.ts b/ui/lib/types/settings.ts
new file mode 100644
index 00000000..b9671ec7
--- /dev/null
+++ b/ui/lib/types/settings.ts
@@ -0,0 +1,7 @@
+export type Settings = {
+  deep_think_llm: string
+  quick_think_llm: string
+  llm_provider: string
+  max_debate_rounds: number
+  max_risk_discuss_rounds: number
+}