diff --git a/web/src/types.ts b/web/src/types.ts
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--- /dev/null
+++ b/web/src/types.ts
@@ -0,0 +1,334 @@
+/**
+ * TypeScript types matching the Rustagent V2 daemon API.
+ * Field names, casing, and nullability match Rust serde serialization exactly.
+ */
+
+// Enum types using string literal unions matching Rust serde serialization
+
+/**
+ * Node type enum.
+ * Rust: #[serde(rename_all = "lowercase")]
+ */
+export type NodeType = 'goal' | 'task' | 'decision' | 'option' | 'outcome' | 'observation' | 'revisit';
+
+/**
+ * Edge type enum.
+ * Rust: #[serde(rename_all = "lowercase")]
+ * WARNING: DependsOn serializes as "dependson" (not "depends_on")
+ * and LeadsTo as "leadsto" (not "leads_to"). This is serde's behavior,
+ * not the Display impl.
+ */
+export type EdgeType = 'contains' | 'dependson' | 'leadsto' | 'chosen' | 'rejected' | 'supersedes' | 'informs';
+
+/**
+ * Node status enum.
+ * Rust: #[serde(rename_all = "snake_case")]
+ */
+export type NodeStatus =
+  | 'pending'
+  | 'active'
+  | 'completed'
+  | 'cancelled'
+  | 'ready'
+  | 'claimed'
+  | 'in_progress'
+  | 'review'
+  | 'blocked'
+  | 'failed'
+  | 'decided'
+  | 'superseded'
+  | 'abandoned'
+  | 'chosen'
+  | 'rejected';
+
+/**
+ * Priority enum.
+ * Rust: #[serde(rename_all = "lowercase")]
+ */
+export type Priority = 'critical' | 'high' | 'medium' | 'low';
+
+// Core API response types
+
+/**
+ * Graph node representing a work item.
+ * 15 fields matching the Rust GraphNode struct.
+ */
+export interface GraphNode {
+  id: string;
+  project_id: string;
+  node_type: NodeType;
+  title: string;
+  description: string;
+  status: NodeStatus;
+  priority: Priority | null;
+  assigned_to: string | null;
+  created_by: string | null;
+  labels: string[];
+  created_at: string;
+  started_at: string | null;
+  completed_at: string | null;
+  blocked_reason: string | null;
+  metadata: Record<string, string>;
+}
+
+/**
+ * Graph edge representing a relationship between nodes.
+ * 6 fields matching the Rust GraphEdge struct.
+ */
+export interface GraphEdge {
+  id: string;
+  edge_type: EdgeType;
+  from_node: string;
+  to_node: string;
+  label: string | null;
+  created_at: string;
+}
+
+/**
+ * Project metadata response.
+ */
+export interface ProjectResponse {
+  id: string;
+  name: string;
+  path: string;
+  registered_at: string;
+}
+
+/**
+ * Session tracking agent work on a goal.
+ */
+export interface Session {
+  id: string;
+  project_id: string;
+  goal_id: string;
+  started_at: string;
+  ended_at: string | null;
+  handoff_notes: string | null;
+  agent_ids: string[];
+  summary: string | null;
+}
+
+/**
+ * Currently active agent on a task.
+ */
+export interface ActiveAgent {
+  agent_id: string;
+  task_id: string;
+  task_title: string;
+  task_status: NodeStatus;
+}
+
+// Composite response types
+
+/**
+ * Node with its incoming and outgoing edges.
+ */
+export interface NodeWithEdges {
+  node: GraphNode;
+  incoming_edges: [GraphEdge, GraphNode][];
+  outgoing_edges: [GraphEdge, GraphNode][];
+}
+
+/**
+ * Goal tree structure: nodes and edges for a goal subtree.
+ */
+export interface GoalTree {
+  nodes: GraphNode[];
+  edges: GraphEdge[];
+}
+
+/**
+ * Decision history: nodes and edges for decisions and choices.
+ */
+export interface DecisionHistory {
+  nodes: GraphNode[];
+  edges: GraphEdge[];
+}
+
+/**
+ * Result of exporting a goal to TOML.
+ */
+export interface ExportResult {
+  goal_id: string;
+  toml: string;
+}
+
+/**
+ * Conflict when importing a graph.
+ */
+export interface ImportConflict {
+  node_id: string;
+  field: string;
+  db_value: string;
+  file_value: string;
+}
+
+/**
+ * Result of importing a graph.
+ */
+export interface ImportResult {
+  added_nodes: number;
+  added_edges: number;
+  conflicts: ImportConflict[];
+  skipped_edges: string[];
+  unchanged: number;
+}
+
+/**
+ * Diff result comparing a graph to the database.
+ */
+export interface DiffResult {
+  added_nodes: string[];
+  changed_nodes: [string, string[]][];
+  removed_nodes: string[];
+  added_edges: string[];
+  removed_edges: string[];
+  unchanged_nodes: number;
+  unchanged_edges: number;
+}
+
+// Request body types
+
+/**
+ * Create project request.
+ */
+export interface CreateProjectRequest {
+  name: string;
+  path: string;
+}
+
+/**
+ * Create goal request.
+ */
+export interface CreateGoalRequest {
+  title: string;
+  description: string;
+  priority?: Priority;
+}
+
+/**
+ * Update node request.
+ */
+export interface UpdateNodeRequest {
+  status?: string;
+  title?: string;
+  description?: string;
+  blocked_reason?: string;
+  metadata?: Record<string, string>;
+}
+
+/**
+ * Create child node request.
+ */
+export interface CreateChildRequest {
+  node_type: NodeType;
+  title: string;
+  description: string;
+  priority?: Priority;
+  metadata?: Record<string, string>;
+}
+
+/**
+ * Create edge request.
+ */
+export interface CreateEdgeRequest {
+  edge_type: EdgeType;
+  from_node: string;
+  to_node: string;
+  label?: string;
+}
+
+/**
+ * Search request for nodes.
+ */
+export interface SearchRequest {
+  query: string;
+  node_type?: NodeType;
+  limit?: number;
+}
+
+/**
+ * Import graph request.
+ */
+export interface ImportRequest {
+  toml: string;
+  strategy?: 'merge' | 'theirs' | 'ours';
+}
+
+/**
+ * WebSocket event discriminated union.
+ * Rust: #[serde(tag = "type", rename_all = "snake_case")]
+ * All events have a `type` field for discrimination.
+ */
+export type WsEvent =
+  | {
+      type: 'agent_spawned';
+      agent_id: string;
+      profile: string;
+      goal_id: string;
+    }
+  | {
+      type: 'agent_progress';
+      agent_id: string;
+      turn: number;
+      summary: string;
+    }
+  | {
+      type: 'agent_completed';
+      agent_id: string;
+      outcome_type: string;
+      summary: string;
+      tokens_used: number | null;
+    }
+  | {
+      type: 'node_created';
+      parent_id: string | null;
+      id: string;
+      project_id: string;
+      node_type: NodeType;
+      title: string;
+      description: string;
+      status: NodeStatus;
+      priority: Priority | null;
+      assigned_to: string | null;
+      created_by: string | null;
+      labels: string[];
+      created_at: string;
+      started_at: string | null;
+      completed_at: string | null;
+      blocked_reason: string | null;
+      metadata: Record<string, string>;
+    }
+  | {
+      type: 'node_status_changed';
+      node_id: string;
+      node_type: string;
+      old_status: string;
+      new_status: string;
+    }
+  | {
+      type: 'edge_created';
+      id: string;
+      edge_type: EdgeType;
+      from_node: string;
+      to_node: string;
+      label: string | null;
+      created_at: string;
+    }
+  | {
+      type: 'session_ended';
+      session_id: string;
+      handoff_notes: string | null;
+    }
+  | {
+      type: 'tool_execution';
+      agent_id: string;
+      tool: string;
+      args: unknown;
+      result: string;
+    }
+  | {
+      type: 'orchestrator_state_changed';
+      goal_id: string;
+      state: string;
+    };