refactor(providers): centralize message handling in provider module

Move provider-specific normalizeMessage and fetchHistory logic out of the legacy
server/providers adapters and into the refactored provider classes so callers can
depend on the main provider contract instead of parallel adapter plumbing.

Add a providers service to resolve concrete providers through the registry and
delegate message normalization/history loading from realtime handlers and the
unified messages route. Add shared TypeScript message/history types and normalized
message helpers so provider implementations and callers use the same contract.

Remove the old adapter registry/files now that Claude, Codex, Cursor, and Gemini
implement the required behavior directly.

server/modules/providers/list/claude/claude.provider.ts

@@ -1,5 +1,57 @@
+import { getSessionMessages } from '@/projects.js';
 import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
 import { ClaudeMcpProvider } from '@/modules/providers/list/claude/claude-mcp.provider.js';
+import type { FetchHistoryOptions, FetchHistoryResult, NormalizedMessage } from '@/shared/types.js';
+import { createNormalizedMessage, generateMessageId, readObjectRecord } from '@/shared/utils.js';
+
+const PROVIDER = 'claude';
+
+type RawProviderMessage = Record<string, any>;
+
+type ClaudeToolResult = {
+  content: unknown;
+  isError: boolean;
+  subagentTools?: unknown;
+  toolUseResult?: unknown;
+};
+
+type ClaudeHistoryResult =
+  | RawProviderMessage[]
+  | {
+      messages?: RawProviderMessage[];
+      total?: number;
+      hasMore?: boolean;
+    };
+
+const loadClaudeSessionMessages = getSessionMessages as unknown as (
+  projectName: string,
+  sessionId: string,
+  limit: number | null,
+  offset: number,
+) => Promise<ClaudeHistoryResult>;
+
+/**
+ * Claude writes internal command and system reminder entries into history.
+ * Those are useful for the CLI but should not appear in the user-facing chat.
+ */
+const INTERNAL_CONTENT_PREFIXES = [
+  '<command-name>',
+  '<command-message>',
+  '<command-args>',
+  '<local-command-stdout>',
+  '<system-reminder>',
+  'Caveat:',
+  'This session is being continued from a previous',
+  '[Request interrupted',
+] as const;
+
+function isInternalContent(content: string): boolean {
+  return INTERNAL_CONTENT_PREFIXES.some((prefix) => content.startsWith(prefix));
+}
+
+function readRawProviderMessage(raw: unknown): RawProviderMessage | null {
+  return readObjectRecord(raw) as RawProviderMessage | null;
+}
 
 export class ClaudeProvider extends AbstractProvider {
   readonly mcp = new ClaudeMcpProvider();
@@ -7,4 +59,260 @@ export class ClaudeProvider extends AbstractProvider {
   constructor() {
     super('claude');
   }
+
+  /**
+   * Normalizes one Claude JSONL entry or live SDK stream event into the shared
+   * message shape consumed by REST and WebSocket clients.
+   */
+  normalizeMessage(rawMessage: unknown, sessionId: string | null): NormalizedMessage[] {
+    const raw = readRawProviderMessage(rawMessage);
+    if (!raw) {
+      return [];
+    }
+
+    if (raw.type === 'content_block_delta' && raw.delta?.text) {
+      return [createNormalizedMessage({ kind: 'stream_delta', content: raw.delta.text, sessionId, provider: PROVIDER })];
+    }
+    if (raw.type === 'content_block_stop') {
+      return [createNormalizedMessage({ kind: 'stream_end', sessionId, provider: PROVIDER })];
+    }
+
+    const messages: NormalizedMessage[] = [];
+    const ts = raw.timestamp || new Date().toISOString();
+    const baseId = raw.uuid || generateMessageId('claude');
+
+    if (raw.message?.role === 'user' && raw.message?.content) {
+      if (Array.isArray(raw.message.content)) {
+        for (const part of raw.message.content) {
+          if (part.type === 'tool_result') {
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_tr_${part.tool_use_id}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'tool_result',
+              toolId: part.tool_use_id,
+              content: typeof part.content === 'string' ? part.content : JSON.stringify(part.content),
+              isError: Boolean(part.is_error),
+              subagentTools: raw.subagentTools,
+              toolUseResult: raw.toolUseResult,
+            }));
+          } else if (part.type === 'text') {
+            const text = part.text || '';
+            if (text && !isInternalContent(text)) {
+              messages.push(createNormalizedMessage({
+                id: `${baseId}_text`,
+                sessionId,
+                timestamp: ts,
+                provider: PROVIDER,
+                kind: 'text',
+                role: 'user',
+                content: text,
+              }));
+            }
+          }
+        }
+
+        if (messages.length === 0) {
+          const textParts = raw.message.content
+            .filter((part: RawProviderMessage) => part.type === 'text')
+            .map((part: RawProviderMessage) => part.text)
+            .filter(Boolean)
+            .join('\n');
+          if (textParts && !isInternalContent(textParts)) {
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_text`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'text',
+              role: 'user',
+              content: textParts,
+            }));
+          }
+        }
+      } else if (typeof raw.message.content === 'string') {
+        const text = raw.message.content;
+        if (text && !isInternalContent(text)) {
+          messages.push(createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'text',
+            role: 'user',
+            content: text,
+          }));
+        }
+      }
+      return messages;
+    }
+
+    if (raw.type === 'thinking' && raw.message?.content) {
+      messages.push(createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'thinking',
+        content: raw.message.content,
+      }));
+      return messages;
+    }
+
+    if (raw.type === 'tool_use' && raw.toolName) {
+      messages.push(createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_use',
+        toolName: raw.toolName,
+        toolInput: raw.toolInput,
+        toolId: raw.toolCallId || baseId,
+      }));
+      return messages;
+    }
+
+    if (raw.type === 'tool_result') {
+      messages.push(createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_result',
+        toolId: raw.toolCallId || '',
+        content: raw.output || '',
+        isError: false,
+      }));
+      return messages;
+    }
+
+    if (raw.message?.role === 'assistant' && raw.message?.content) {
+      if (Array.isArray(raw.message.content)) {
+        let partIndex = 0;
+        for (const part of raw.message.content) {
+          if (part.type === 'text' && part.text) {
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_${partIndex}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'text',
+              role: 'assistant',
+              content: part.text,
+            }));
+          } else if (part.type === 'tool_use') {
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_${partIndex}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'tool_use',
+              toolName: part.name,
+              toolInput: part.input,
+              toolId: part.id,
+            }));
+          } else if (part.type === 'thinking' && part.thinking) {
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_${partIndex}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'thinking',
+              content: part.thinking,
+            }));
+          }
+          partIndex++;
+        }
+      } else if (typeof raw.message.content === 'string') {
+        messages.push(createNormalizedMessage({
+          id: baseId,
+          sessionId,
+          timestamp: ts,
+          provider: PROVIDER,
+          kind: 'text',
+          role: 'assistant',
+          content: raw.message.content,
+        }));
+      }
+      return messages;
+    }
+
+    return messages;
+  }
+
+  /**
+   * Loads Claude JSONL history for a project/session and returns normalized
+   * messages, preserving the existing pagination behavior from projects.js.
+   */
+  async fetchHistory(
+    sessionId: string,
+    options: FetchHistoryOptions = {},
+  ): Promise<FetchHistoryResult> {
+    const { projectName, limit = null, offset = 0 } = options;
+    if (!projectName) {
+      return { messages: [], total: 0, hasMore: false, offset: 0, limit: null };
+    }
+
+    let result: ClaudeHistoryResult;
+    try {
+      result = await loadClaudeSessionMessages(projectName, sessionId, limit, offset);
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.warn(`[ClaudeProvider] Failed to load session ${sessionId}:`, message);
+      return { messages: [], total: 0, hasMore: false, offset: 0, limit: null };
+    }
+
+    const rawMessages = Array.isArray(result) ? result : (result.messages || []);
+    const total = Array.isArray(result) ? rawMessages.length : (result.total || 0);
+    const hasMore = Array.isArray(result) ? false : Boolean(result.hasMore);
+
+    const toolResultMap = new Map<string, ClaudeToolResult>();
+    for (const raw of rawMessages) {
+      if (raw.message?.role === 'user' && Array.isArray(raw.message?.content)) {
+        for (const part of raw.message.content) {
+          if (part.type === 'tool_result' && part.tool_use_id) {
+            toolResultMap.set(part.tool_use_id, {
+              content: part.content,
+              isError: Boolean(part.is_error),
+              subagentTools: raw.subagentTools,
+              toolUseResult: raw.toolUseResult,
+            });
+          }
+        }
+      }
+    }
+
+    const normalized: NormalizedMessage[] = [];
+    for (const raw of rawMessages) {
+      normalized.push(...this.normalizeMessage(raw, sessionId));
+    }
+
+    for (const msg of normalized) {
+      if (msg.kind === 'tool_use' && msg.toolId && toolResultMap.has(msg.toolId)) {
+        const toolResult = toolResultMap.get(msg.toolId);
+        if (!toolResult) {
+          continue;
+        }
+
+        msg.toolResult = {
+          content: typeof toolResult.content === 'string'
+            ? toolResult.content
+            : JSON.stringify(toolResult.content),
+          isError: toolResult.isError,
+          toolUseResult: toolResult.toolUseResult,
+        };
+        msg.subagentTools = toolResult.subagentTools;
+      }
+    }
+
+    return {
+      messages: normalized,
+      total,
+      hasMore,
+      offset,
+      limit,
+    };
+  }
 }

server/modules/providers/list/codex/codex.provider.ts

@@ -1,5 +1,31 @@
+import { getCodexSessionMessages } from '@/projects.js';
 import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
 import { CodexMcpProvider } from '@/modules/providers/list/codex/codex-mcp.provider.js';
+import type { FetchHistoryOptions, FetchHistoryResult, NormalizedMessage } from '@/shared/types.js';
+import { createNormalizedMessage, generateMessageId, readObjectRecord } from '@/shared/utils.js';
+
+const PROVIDER = 'codex';
+
+type RawProviderMessage = Record<string, any>;
+
+type CodexHistoryResult =
+  | RawProviderMessage[]
+  | {
+      messages?: RawProviderMessage[];
+      total?: number;
+      hasMore?: boolean;
+      tokenUsage?: unknown;
+    };
+
+const loadCodexSessionMessages = getCodexSessionMessages as unknown as (
+  sessionId: string,
+  limit: number | null,
+  offset: number,
+) => Promise<CodexHistoryResult>;
+
+function readRawProviderMessage(raw: unknown): RawProviderMessage | null {
+  return readObjectRecord(raw) as RawProviderMessage | null;
+}
 
 export class CodexProvider extends AbstractProvider {
   readonly mcp = new CodexMcpProvider();
@@ -7,4 +33,300 @@ export class CodexProvider extends AbstractProvider {
   constructor() {
     super('codex');
   }
+
+  /**
+   * Normalizes a persisted Codex JSONL entry.
+   *
+   * Live Codex SDK events are transformed before they reach normalizeMessage(),
+   * while history entries already use a compact message/tool shape from projects.js.
+   */
+  private normalizeHistoryEntry(raw: RawProviderMessage, sessionId: string | null): NormalizedMessage[] {
+    const ts = raw.timestamp || new Date().toISOString();
+    const baseId = raw.uuid || generateMessageId('codex');
+
+    if (raw.message?.role === 'user') {
+      const content = typeof raw.message.content === 'string'
+        ? raw.message.content
+        : Array.isArray(raw.message.content)
+          ? raw.message.content
+              .map((part: string | RawProviderMessage) => typeof part === 'string' ? part : part?.text || '')
+              .filter(Boolean)
+              .join('\n')
+          : String(raw.message.content || '');
+      if (!content.trim()) {
+        return [];
+      }
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'text',
+        role: 'user',
+        content,
+      })];
+    }
+
+    if (raw.message?.role === 'assistant') {
+      const content = typeof raw.message.content === 'string'
+        ? raw.message.content
+        : Array.isArray(raw.message.content)
+          ? raw.message.content
+              .map((part: string | RawProviderMessage) => typeof part === 'string' ? part : part?.text || '')
+              .filter(Boolean)
+              .join('\n')
+          : '';
+      if (!content.trim()) {
+        return [];
+      }
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'text',
+        role: 'assistant',
+        content,
+      })];
+    }
+
+    if (raw.type === 'thinking' || raw.isReasoning) {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'thinking',
+        content: raw.message?.content || '',
+      })];
+    }
+
+    if (raw.type === 'tool_use' || raw.toolName) {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_use',
+        toolName: raw.toolName || 'Unknown',
+        toolInput: raw.toolInput,
+        toolId: raw.toolCallId || baseId,
+      })];
+    }
+
+    if (raw.type === 'tool_result') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_result',
+        toolId: raw.toolCallId || '',
+        content: raw.output || '',
+        isError: Boolean(raw.isError),
+      })];
+    }
+
+    return [];
+  }
+
+  /**
+   * Normalizes either a Codex history entry or a transformed live SDK event.
+   */
+  normalizeMessage(rawMessage: unknown, sessionId: string | null): NormalizedMessage[] {
+    const raw = readRawProviderMessage(rawMessage);
+    if (!raw) {
+      return [];
+    }
+
+    if (raw.message?.role) {
+      return this.normalizeHistoryEntry(raw, sessionId);
+    }
+
+    const ts = raw.timestamp || new Date().toISOString();
+    const baseId = raw.uuid || generateMessageId('codex');
+
+    if (raw.type === 'item') {
+      switch (raw.itemType) {
+        case 'agent_message':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'text',
+            role: 'assistant',
+            content: raw.message?.content || '',
+          })];
+        case 'reasoning':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'thinking',
+            content: raw.message?.content || '',
+          })];
+        case 'command_execution':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: 'Bash',
+            toolInput: { command: raw.command },
+            toolId: baseId,
+            output: raw.output,
+            exitCode: raw.exitCode,
+            status: raw.status,
+          })];
+        case 'file_change':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: 'FileChanges',
+            toolInput: raw.changes,
+            toolId: baseId,
+            status: raw.status,
+          })];
+        case 'mcp_tool_call':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: raw.tool || 'MCP',
+            toolInput: raw.arguments,
+            toolId: baseId,
+            server: raw.server,
+            result: raw.result,
+            error: raw.error,
+            status: raw.status,
+          })];
+        case 'web_search':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: 'WebSearch',
+            toolInput: { query: raw.query },
+            toolId: baseId,
+          })];
+        case 'todo_list':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: 'TodoList',
+            toolInput: { items: raw.items },
+            toolId: baseId,
+          })];
+        case 'error':
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'error',
+            content: raw.message?.content || 'Unknown error',
+          })];
+        default:
+          return [createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'tool_use',
+            toolName: raw.itemType || 'Unknown',
+            toolInput: raw.item || raw,
+            toolId: baseId,
+          })];
+      }
+    }
+
+    if (raw.type === 'turn_complete') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'complete',
+      })];
+    }
+    if (raw.type === 'turn_failed') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'error',
+        content: raw.error?.message || 'Turn failed',
+      })];
+    }
+
+    return [];
+  }
+
+  /**
+   * Loads Codex JSONL history and keeps token usage metadata when projects.js
+   * provides it.
+   */
+  async fetchHistory(
+    sessionId: string,
+    options: FetchHistoryOptions = {},
+  ): Promise<FetchHistoryResult> {
+    const { limit = null, offset = 0 } = options;
+
+    let result: CodexHistoryResult;
+    try {
+      result = await loadCodexSessionMessages(sessionId, limit, offset);
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.warn(`[CodexProvider] Failed to load session ${sessionId}:`, message);
+      return { messages: [], total: 0, hasMore: false, offset: 0, limit: null };
+    }
+
+    const rawMessages = Array.isArray(result) ? result : (result.messages || []);
+    const total = Array.isArray(result) ? rawMessages.length : (result.total || 0);
+    const hasMore = Array.isArray(result) ? false : Boolean(result.hasMore);
+    const tokenUsage = Array.isArray(result) ? undefined : result.tokenUsage;
+
+    const normalized: NormalizedMessage[] = [];
+    for (const raw of rawMessages) {
+      normalized.push(...this.normalizeHistoryEntry(raw, sessionId));
+    }
+
+    const toolResultMap = new Map<string, NormalizedMessage>();
+    for (const msg of normalized) {
+      if (msg.kind === 'tool_result' && msg.toolId) {
+        toolResultMap.set(msg.toolId, msg);
+      }
+    }
+    for (const msg of normalized) {
+      if (msg.kind === 'tool_use' && msg.toolId && toolResultMap.has(msg.toolId)) {
+        const toolResult = toolResultMap.get(msg.toolId);
+        if (toolResult) {
+          msg.toolResult = { content: toolResult.content, isError: toolResult.isError };
+        }
+      }
+    }
+
+    return {
+      messages: normalized,
+      total,
+      hasMore,
+      offset,
+      limit,
+      tokenUsage,
+    };
+  }
 }

server/modules/providers/list/cursor/cursor.provider.ts

@@ -1,5 +1,36 @@
+import crypto from 'node:crypto';
+import os from 'node:os';
+import path from 'node:path';
+
 import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
 import { CursorMcpProvider } from '@/modules/providers/list/cursor/cursor-mcp.provider.js';
+import type { FetchHistoryOptions, FetchHistoryResult, NormalizedMessage } from '@/shared/types.js';
+import { createNormalizedMessage, generateMessageId, readObjectRecord } from '@/shared/utils.js';
+
+const PROVIDER = 'cursor';
+
+type RawProviderMessage = Record<string, any>;
+
+type CursorDbBlob = {
+  rowid: number;
+  id: string;
+  data?: Buffer;
+};
+
+type CursorJsonBlob = CursorDbBlob & {
+  parsed: RawProviderMessage;
+};
+
+type CursorMessageBlob = {
+  id: string;
+  sequence: number;
+  rowid: number;
+  content: RawProviderMessage;
+};
+
+function readRawProviderMessage(raw: unknown): RawProviderMessage | null {
+  return readObjectRecord(raw) as RawProviderMessage | null;
+}
 
 export class CursorProvider extends AbstractProvider {
   readonly mcp = new CursorMcpProvider();
@@ -7,4 +38,363 @@ export class CursorProvider extends AbstractProvider {
   constructor() {
     super('cursor');
   }
+
+  /**
+   * Loads Cursor's SQLite blob DAG and returns message blobs in conversation
+   * order. Cursor history is stored as content-addressed blobs rather than JSONL.
+   */
+  private async loadCursorBlobs(sessionId: string, projectPath: string): Promise<CursorMessageBlob[]> {
+    const sqlite3Module = await import('sqlite3');
+    const sqlite3 = sqlite3Module.default;
+    const { open } = await import('sqlite');
+
+    const cwdId = crypto.createHash('md5').update(projectPath || process.cwd()).digest('hex');
+    const storeDbPath = path.join(os.homedir(), '.cursor', 'chats', cwdId, sessionId, 'store.db');
+
+    const db = await open({
+      filename: storeDbPath,
+      driver: sqlite3.Database,
+      mode: sqlite3.OPEN_READONLY,
+    });
+
+    try {
+      const allBlobs = await db.all('SELECT rowid, id, data FROM blobs') as CursorDbBlob[];
+
+      const blobMap = new Map<string, CursorDbBlob>();
+      const parentRefs = new Map<string, string[]>();
+      const childRefs = new Map<string, string[]>();
+      const jsonBlobs: CursorJsonBlob[] = [];
+
+      for (const blob of allBlobs) {
+        blobMap.set(blob.id, blob);
+
+        if (blob.data && blob.data[0] === 0x7B) {
+          try {
+            const parsed = JSON.parse(blob.data.toString('utf8')) as RawProviderMessage;
+            jsonBlobs.push({ ...blob, parsed });
+          } catch {
+            // Cursor can include binary or partial blobs; only JSON blobs become messages.
+          }
+        } else if (blob.data) {
+          const parents: string[] = [];
+          let i = 0;
+          while (i < blob.data.length - 33) {
+            if (blob.data[i] === 0x0A && blob.data[i + 1] === 0x20) {
+              const parentHash = blob.data.slice(i + 2, i + 34).toString('hex');
+              if (blobMap.has(parentHash)) {
+                parents.push(parentHash);
+              }
+              i += 34;
+            } else {
+              i++;
+            }
+          }
+          if (parents.length > 0) {
+            parentRefs.set(blob.id, parents);
+            for (const parentId of parents) {
+              if (!childRefs.has(parentId)) {
+                childRefs.set(parentId, []);
+              }
+              childRefs.get(parentId)?.push(blob.id);
+            }
+          }
+        }
+      }
+
+      const visited = new Set<string>();
+      const sorted: CursorDbBlob[] = [];
+      const visit = (nodeId: string): void => {
+        if (visited.has(nodeId)) {
+          return;
+        }
+        visited.add(nodeId);
+        for (const parentId of parentRefs.get(nodeId) || []) {
+          visit(parentId);
+        }
+        const blob = blobMap.get(nodeId);
+        if (blob) {
+          sorted.push(blob);
+        }
+      };
+
+      for (const blob of allBlobs) {
+        if (!parentRefs.has(blob.id)) {
+          visit(blob.id);
+        }
+      }
+      for (const blob of allBlobs) {
+        visit(blob.id);
+      }
+
+      const messageOrder = new Map<string, number>();
+      let orderIndex = 0;
+      for (const blob of sorted) {
+        if (blob.data && blob.data[0] !== 0x7B) {
+          for (const jsonBlob of jsonBlobs) {
+            try {
+              const idBytes = Buffer.from(jsonBlob.id, 'hex');
+              if (blob.data.includes(idBytes) && !messageOrder.has(jsonBlob.id)) {
+                messageOrder.set(jsonBlob.id, orderIndex++);
+              }
+            } catch {
+              // Ignore malformed blob ids that cannot be decoded as hex.
+            }
+          }
+        }
+      }
+
+      const sortedJsonBlobs = jsonBlobs.sort((a, b) => {
+        const aOrder = messageOrder.get(a.id) ?? Number.MAX_SAFE_INTEGER;
+        const bOrder = messageOrder.get(b.id) ?? Number.MAX_SAFE_INTEGER;
+        return aOrder !== bOrder ? aOrder - bOrder : a.rowid - b.rowid;
+      });
+
+      const messages: CursorMessageBlob[] = [];
+      for (let idx = 0; idx < sortedJsonBlobs.length; idx++) {
+        const blob = sortedJsonBlobs[idx];
+        const parsed = blob.parsed;
+        const role = parsed?.role || parsed?.message?.role;
+        if (role === 'system') {
+          continue;
+        }
+        messages.push({
+          id: blob.id,
+          sequence: idx + 1,
+          rowid: blob.rowid,
+          content: parsed,
+        });
+      }
+
+      return messages;
+    } finally {
+      await db.close();
+    }
+  }
+
+  /**
+   * Normalizes live Cursor CLI NDJSON events. Persisted Cursor history is
+   * normalized from SQLite blobs in fetchHistory().
+   */
+  normalizeMessage(rawMessage: unknown, sessionId: string | null): NormalizedMessage[] {
+    const raw = readRawProviderMessage(rawMessage);
+    if (raw?.type === 'assistant' && raw.message?.content?.[0]?.text) {
+      return [createNormalizedMessage({
+        kind: 'stream_delta',
+        content: raw.message.content[0].text,
+        sessionId,
+        provider: PROVIDER,
+      })];
+    }
+
+    if (typeof rawMessage === 'string' && rawMessage.trim()) {
+      return [createNormalizedMessage({
+        kind: 'stream_delta',
+        content: rawMessage,
+        sessionId,
+        provider: PROVIDER,
+      })];
+    }
+
+    return [];
+  }
+
+  /**
+   * Fetches and paginates Cursor session history from its project-scoped store.db.
+   */
+  async fetchHistory(
+    sessionId: string,
+    options: FetchHistoryOptions = {},
+  ): Promise<FetchHistoryResult> {
+    const { projectPath = '', limit = null, offset = 0 } = options;
+
+    try {
+      const blobs = await this.loadCursorBlobs(sessionId, projectPath);
+      const allNormalized = this.normalizeCursorBlobs(blobs, sessionId);
+
+      if (limit !== null && limit > 0) {
+        const start = offset;
+        const page = allNormalized.slice(start, start + limit);
+        return {
+          messages: page,
+          total: allNormalized.length,
+          hasMore: start + limit < allNormalized.length,
+          offset,
+          limit,
+        };
+      }
+
+      return {
+        messages: allNormalized,
+        total: allNormalized.length,
+        hasMore: false,
+        offset: 0,
+        limit: null,
+      };
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.warn(`[CursorProvider] Failed to load session ${sessionId}:`, message);
+      return { messages: [], total: 0, hasMore: false, offset: 0, limit: null };
+    }
+  }
+
+  /**
+   * Converts Cursor SQLite message blobs into normalized messages and attaches
+   * matching tool results to their tool_use entries.
+   */
+  private normalizeCursorBlobs(blobs: CursorMessageBlob[], sessionId: string | null): NormalizedMessage[] {
+    const messages: NormalizedMessage[] = [];
+    const toolUseMap = new Map<string, NormalizedMessage>();
+    const baseTime = Date.now();
+
+    for (let i = 0; i < blobs.length; i++) {
+      const blob = blobs[i];
+      const content = blob.content;
+      const ts = new Date(baseTime + (blob.sequence ?? i) * 100).toISOString();
+      const baseId = blob.id || generateMessageId('cursor');
+
+      try {
+        if (!content?.role || !content?.content) {
+          if (content?.message?.role && content?.message?.content) {
+            if (content.message.role === 'system') {
+              continue;
+            }
+            const role = content.message.role === 'user' ? 'user' : 'assistant';
+            let text = '';
+            if (Array.isArray(content.message.content)) {
+              text = content.message.content
+                .map((part: string | RawProviderMessage) => typeof part === 'string' ? part : part?.text || '')
+                .filter(Boolean)
+                .join('\n');
+            } else if (typeof content.message.content === 'string') {
+              text = content.message.content;
+            }
+            if (text?.trim()) {
+              messages.push(createNormalizedMessage({
+                id: baseId,
+                sessionId,
+                timestamp: ts,
+                provider: PROVIDER,
+                kind: 'text',
+                role,
+                content: text,
+                sequence: blob.sequence,
+                rowid: blob.rowid,
+              }));
+            }
+          }
+          continue;
+        }
+
+        if (content.role === 'system') {
+          continue;
+        }
+
+        if (content.role === 'tool') {
+          const toolItems = Array.isArray(content.content) ? content.content : [];
+          for (const item of toolItems) {
+            if (item?.type !== 'tool-result') {
+              continue;
+            }
+            const toolCallId = item.toolCallId || content.id;
+            messages.push(createNormalizedMessage({
+              id: `${baseId}_tr`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'tool_result',
+              toolId: toolCallId,
+              content: item.result || '',
+              isError: false,
+            }));
+          }
+          continue;
+        }
+
+        const role = content.role === 'user' ? 'user' : 'assistant';
+
+        if (Array.isArray(content.content)) {
+          for (let partIdx = 0; partIdx < content.content.length; partIdx++) {
+            const part = content.content[partIdx];
+
+            if (part?.type === 'text' && part?.text) {
+              messages.push(createNormalizedMessage({
+                id: `${baseId}_${partIdx}`,
+                sessionId,
+                timestamp: ts,
+                provider: PROVIDER,
+                kind: 'text',
+                role,
+                content: part.text,
+                sequence: blob.sequence,
+                rowid: blob.rowid,
+              }));
+            } else if (part?.type === 'reasoning' && part?.text) {
+              messages.push(createNormalizedMessage({
+                id: `${baseId}_${partIdx}`,
+                sessionId,
+                timestamp: ts,
+                provider: PROVIDER,
+                kind: 'thinking',
+                content: part.text,
+              }));
+            } else if (part?.type === 'tool-call' || part?.type === 'tool_use') {
+              const rawToolName = part.toolName || part.name || 'Unknown Tool';
+              const toolName = rawToolName === 'ApplyPatch' ? 'Edit' : rawToolName;
+              const toolId = part.toolCallId || part.id || `tool_${i}_${partIdx}`;
+              const message = createNormalizedMessage({
+                id: `${baseId}_${partIdx}`,
+                sessionId,
+                timestamp: ts,
+                provider: PROVIDER,
+                kind: 'tool_use',
+                toolName,
+                toolInput: part.args || part.input,
+                toolId,
+              });
+              messages.push(message);
+              toolUseMap.set(toolId, message);
+            }
+          }
+        } else if (typeof content.content === 'string' && content.content.trim()) {
+          messages.push(createNormalizedMessage({
+            id: baseId,
+            sessionId,
+            timestamp: ts,
+            provider: PROVIDER,
+            kind: 'text',
+            role,
+            content: content.content,
+            sequence: blob.sequence,
+            rowid: blob.rowid,
+          }));
+        }
+      } catch (error) {
+        console.warn('Error normalizing cursor blob:', error);
+      }
+    }
+
+    for (const msg of messages) {
+      if (msg.kind === 'tool_result' && msg.toolId && toolUseMap.has(msg.toolId)) {
+        const toolUse = toolUseMap.get(msg.toolId);
+        if (toolUse) {
+          toolUse.toolResult = {
+            content: msg.content,
+            isError: msg.isError,
+          };
+        }
+      }
+    }
+
+    messages.sort((a, b) => {
+      if (a.sequence !== undefined && b.sequence !== undefined) {
+        return a.sequence - b.sequence;
+      }
+      if (a.rowid !== undefined && b.rowid !== undefined) {
+        return a.rowid - b.rowid;
+      }
+      return new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime();
+    });
+
+    return messages;
+  }
 }

server/modules/providers/list/gemini/gemini.provider.ts

@@ -1,5 +1,17 @@
+import sessionManager from '@/sessionManager.js';
+import { getGeminiCliSessionMessages } from '@/projects.js';
 import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
 import { GeminiMcpProvider } from '@/modules/providers/list/gemini/gemini-mcp.provider.js';
+import type { FetchHistoryOptions, FetchHistoryResult, NormalizedMessage } from '@/shared/types.js';
+import { createNormalizedMessage, generateMessageId, readObjectRecord } from '@/shared/utils.js';
+
+const PROVIDER = 'gemini';
+
+type RawProviderMessage = Record<string, any>;
+
+function readRawProviderMessage(raw: unknown): RawProviderMessage | null {
+  return readObjectRecord(raw) as RawProviderMessage | null;
+}
 
 export class GeminiProvider extends AbstractProvider {
   readonly mcp = new GeminiMcpProvider();
@@ -7,4 +19,214 @@ export class GeminiProvider extends AbstractProvider {
   constructor() {
     super('gemini');
   }
+
+  /**
+   * Normalizes live Gemini stream-json events into the shared message shape.
+   *
+   * Gemini history uses a different session file shape, so fetchHistory handles
+   * that separately after loading raw persisted messages.
+   */
+  normalizeMessage(rawMessage: unknown, sessionId: string | null): NormalizedMessage[] {
+    const raw = readRawProviderMessage(rawMessage);
+    if (!raw) {
+      return [];
+    }
+
+    const ts = raw.timestamp || new Date().toISOString();
+    const baseId = raw.uuid || generateMessageId('gemini');
+
+    if (raw.type === 'message' && raw.role === 'assistant') {
+      const content = raw.content || '';
+      const messages: NormalizedMessage[] = [];
+      if (content) {
+        messages.push(createNormalizedMessage({
+          id: baseId,
+          sessionId,
+          timestamp: ts,
+          provider: PROVIDER,
+          kind: 'stream_delta',
+          content,
+        }));
+      }
+      if (raw.delta !== true) {
+        messages.push(createNormalizedMessage({
+          sessionId,
+          timestamp: ts,
+          provider: PROVIDER,
+          kind: 'stream_end',
+        }));
+      }
+      return messages;
+    }
+
+    if (raw.type === 'tool_use') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_use',
+        toolName: raw.tool_name,
+        toolInput: raw.parameters || {},
+        toolId: raw.tool_id || baseId,
+      })];
+    }
+
+    if (raw.type === 'tool_result') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'tool_result',
+        toolId: raw.tool_id || '',
+        content: raw.output === undefined ? '' : String(raw.output),
+        isError: raw.status === 'error',
+      })];
+    }
+
+    if (raw.type === 'result') {
+      const messages = [createNormalizedMessage({
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'stream_end',
+      })];
+      if (raw.stats?.total_tokens) {
+        messages.push(createNormalizedMessage({
+          sessionId,
+          timestamp: ts,
+          provider: PROVIDER,
+          kind: 'status',
+          text: 'Complete',
+          tokens: raw.stats.total_tokens,
+          canInterrupt: false,
+        }));
+      }
+      return messages;
+    }
+
+    if (raw.type === 'error') {
+      return [createNormalizedMessage({
+        id: baseId,
+        sessionId,
+        timestamp: ts,
+        provider: PROVIDER,
+        kind: 'error',
+        content: raw.error || raw.message || 'Unknown Gemini streaming error',
+      })];
+    }
+
+    return [];
+  }
+
+  /**
+   * Loads Gemini history from the in-memory session manager first, then falls
+   * back to Gemini CLI session files on disk.
+   */
+  async fetchHistory(
+    sessionId: string,
+    _options: FetchHistoryOptions = {},
+  ): Promise<FetchHistoryResult> {
+    let rawMessages: RawProviderMessage[];
+    try {
+      rawMessages = sessionManager.getSessionMessages(sessionId) as RawProviderMessage[];
+
+      if (rawMessages.length === 0) {
+        rawMessages = await getGeminiCliSessionMessages(sessionId) as RawProviderMessage[];
+      }
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.warn(`[GeminiProvider] Failed to load session ${sessionId}:`, message);
+      return { messages: [], total: 0, hasMore: false, offset: 0, limit: null };
+    }
+
+    const normalized: NormalizedMessage[] = [];
+    for (let i = 0; i < rawMessages.length; i++) {
+      const raw = rawMessages[i];
+      const ts = raw.timestamp || new Date().toISOString();
+      const baseId = raw.uuid || generateMessageId('gemini');
+
+      const role = raw.message?.role || raw.role;
+      const content = raw.message?.content || raw.content;
+
+      if (!role || !content) {
+        continue;
+      }
+
+      const normalizedRole = role === 'user' ? 'user' : 'assistant';
+
+      if (Array.isArray(content)) {
+        for (let partIdx = 0; partIdx < content.length; partIdx++) {
+          const part = content[partIdx];
+          if (part.type === 'text' && part.text) {
+            normalized.push(createNormalizedMessage({
+              id: `${baseId}_${partIdx}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'text',
+              role: normalizedRole,
+              content: part.text,
+            }));
+          } else if (part.type === 'tool_use') {
+            normalized.push(createNormalizedMessage({
+              id: `${baseId}_${partIdx}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'tool_use',
+              toolName: part.name,
+              toolInput: part.input,
+              toolId: part.id || generateMessageId('gemini_tool'),
+            }));
+          } else if (part.type === 'tool_result') {
+            normalized.push(createNormalizedMessage({
+              id: `${baseId}_${partIdx}`,
+              sessionId,
+              timestamp: ts,
+              provider: PROVIDER,
+              kind: 'tool_result',
+              toolId: part.tool_use_id || '',
+              content: part.content === undefined ? '' : String(part.content),
+              isError: Boolean(part.is_error),
+            }));
+          }
+        }
+      } else if (typeof content === 'string' && content.trim()) {
+        normalized.push(createNormalizedMessage({
+          id: baseId,
+          sessionId,
+          timestamp: ts,
+          provider: PROVIDER,
+          kind: 'text',
+          role: normalizedRole,
+          content,
+        }));
+      }
+    }
+
+    const toolResultMap = new Map<string, NormalizedMessage>();
+    for (const msg of normalized) {
+      if (msg.kind === 'tool_result' && msg.toolId) {
+        toolResultMap.set(msg.toolId, msg);
+      }
+    }
+    for (const msg of normalized) {
+      if (msg.kind === 'tool_use' && msg.toolId && toolResultMap.has(msg.toolId)) {
+        const toolResult = toolResultMap.get(msg.toolId);
+        if (toolResult) {
+          msg.toolResult = { content: toolResult.content, isError: toolResult.isError };
+        }
+      }
+    }
+
+    return {
+      messages: normalized,
+      total: normalized.length,
+      hasMore: false,
+      offset: 0,
+      limit: null,
+    };
+  }
 }

server/modules/providers/provider.registry.ts

@@ -14,7 +14,7 @@ const providers: Record<LLMProvider, IProvider> = {
 };
 
 /**
- * Central registry for resolving provider MCP implementations by id.
+ * Central registry for resolving concrete provider implementations by id.
  */
 export const providerRegistry = {
   listProviders(): IProvider[] {

server/modules/providers/services/providers.service.ts

@@ -0,0 +1,36 @@
+import { providerRegistry } from '@/modules/providers/provider.registry.js';
+import type {
+  FetchHistoryOptions,
+  FetchHistoryResult,
+  LLMProvider,
+  NormalizedMessage,
+} from '@/shared/types.js';
+
+/**
+ * Application service for provider message operations.
+ *
+ * Callers pass a provider id and this service resolves the concrete provider
+ * class, keeping normalization/history call sites decoupled from implementation
+ * file layout.
+ */
+export const providersService = {
+  listProviderIds(): LLMProvider[] {
+    return providerRegistry.listProviders().map((provider) => provider.id);
+  },
+
+  normalizeMessage(
+    providerName: string,
+    raw: unknown,
+    sessionId: string | null,
+  ): NormalizedMessage[] {
+    return providerRegistry.resolveProvider(providerName).normalizeMessage(raw, sessionId);
+  },
+
+  fetchHistory(
+    providerName: string,
+    sessionId: string,
+    options?: FetchHistoryOptions,
+  ): Promise<FetchHistoryResult> {
+    return providerRegistry.resolveProvider(providerName).fetchHistory(sessionId, options);
+  },
+};

server/modules/providers/shared/base/abstract.provider.ts

@@ -1,8 +1,16 @@
 import type { IProvider, IProviderMcpRuntime } from '@/shared/interfaces.js';
-import type { LLMProvider } from '@/shared/types.js';
+import type {
+  FetchHistoryOptions,
+  FetchHistoryResult,
+  LLMProvider,
+  NormalizedMessage,
+} from '@/shared/types.js';
 
 /**
- * Shared MCP-only provider base.
+ * Shared provider base.
+ *
+ * Concrete providers must implement message normalization and history loading
+ * because both behaviors depend on each provider's native SDK/CLI event format.
  */
 export abstract class AbstractProvider implements IProvider {
   readonly id: LLMProvider;
@@ -11,4 +19,11 @@ export abstract class AbstractProvider implements IProvider {
   protected constructor(id: LLMProvider) {
     this.id = id;
   }
+
+  abstract normalizeMessage(raw: unknown, sessionId: string | null): NormalizedMessage[];
+
+  abstract fetchHistory(
+    sessionId: string,
+    options?: FetchHistoryOptions,
+  ): Promise<FetchHistoryResult>;
 }