diff --git a/src/providers/chatgpt.py b/src/providers/chatgpt.py
new file mode 100644
index 0000000..86707f8
--- /dev/null
+++ b/src/providers/chatgpt.py
@@ -0,0 +1,254 @@
+"""ChatGPT provider — accesses chat.openai.com internal web API."""
+
+import logging
+import os
+from typing import Any
+
+from src.providers.base import BaseProvider, ProviderError
+
+logger = logging.getLogger(__name__)
+
+BASE_URL = "https://chatgpt.com/backend-api"
+
+
+class ChatGPTProvider(BaseProvider):
+    """Provider for ChatGPT conversations via the internal web API.
+
+    Authentication: Authorization: Bearer <CHATGPT_SESSION_TOKEN>
+    Token: __Secure-next-auth.session-token cookie value (a JWT).
+    Typical validity: ~7 days.
+    """
+
+    provider_name = "chatgpt"
+
+    def __init__(self, session_token: str | None = None) -> None:
+        super().__init__()
+        token = session_token or os.getenv("CHATGPT_SESSION_TOKEN", "").strip()
+        if not token:
+            raise ProviderError(
+                self.provider_name,
+                "init",
+                RuntimeError(
+                    "CHATGPT_SESSION_TOKEN is not set. "
+                    "Run 'python -m src.main auth' to configure it."
+                ),
+            )
+        # Never log the token value
+        self._session.headers.update(
+            {
+                "Authorization": f"Bearer {token}",
+                "Referer": "https://chatgpt.com/",
+                "Origin": "https://chatgpt.com",
+            }
+        )
+        logger.debug("[chatgpt] Session initialised (token: [REDACTED])")
+
+    def _handle_401(self) -> None:
+        msg = (
+            "[chatgpt] Authentication failed (401 Unauthorized). "
+            "Your __Secure-next-auth.session-token has likely expired (~7 day lifetime). "
+            "To refresh: open chatgpt.com in Chrome → F12 → Application → Cookies "
+            "→ find '__Secure-next-auth.session-token' → copy the value. "
+            "Then run 'python -m src.main auth' or update CHATGPT_SESSION_TOKEN in .env."
+        )
+        logger.error(msg)
+        raise ProviderError(
+            self.provider_name,
+            "authentication",
+            RuntimeError("401 Unauthorized — ChatGPT token expired"),
+        )
+
+    def list_conversations(self, offset: int = 0, limit: int = 100) -> list[dict]:
+        """Fetch one page of conversations.
+
+        Returns:
+            List of conversation summary dicts.
+        """
+        url = f"{BASE_URL}/conversations"
+        params = {"offset": offset, "limit": limit, "order": "updated"}
+        try:
+            data = self._make_request("GET", url, params=params)
+        except ProviderError:
+            raise
+        except Exception as e:
+            raise ProviderError(self.provider_name, "list_conversations", e) from e
+
+        if not isinstance(data, dict):
+            self._warn_unexpected_schema("list_conversations", "root")
+            return []
+
+        items = data.get("items")
+        if items is None:
+            self._warn_unexpected_schema("list_conversations", "items")
+            return []
+
+        return items
+
+    def get_conversation(self, conv_id: str) -> dict:
+        """Fetch full conversation detail for a single ID."""
+        url = f"{BASE_URL}/conversation/{conv_id}"
+        try:
+            data = self._make_request("GET", url)
+        except ProviderError:
+            raise
+        except Exception as e:
+            raise ProviderError(self.provider_name, "get_conversation", e) from e
+
+        if not isinstance(data, dict):
+            self._warn_unexpected_schema("get_conversation", "root")
+            return {}
+
+        return data
+
+    def normalize_conversation(self, raw: dict) -> dict:
+        """Transform ChatGPT raw schema to the common normalized schema.
+
+        ChatGPT stores messages in a nested ``mapping`` dict where each node
+        has an ``id``, ``message``, and ``children`` list. We walk the tree
+        from the root node to build a flat ordered message list.
+        """
+        conv_id = raw.get("id", "")
+        title = raw.get("title") or "Untitled"
+        created_at = _ts_to_iso(raw.get("create_time"))
+        updated_at = _ts_to_iso(raw.get("update_time"))
+
+        # Project info — ChatGPT calls it "gizmo_id" or stores project info differently.
+        # As of 2024, personal projects appear as a separate projects API; conversations
+        # linked to a project have a non-null `workspace_id` or similar field.
+        # We use `project_title` if present, else None.
+        project: str | None = raw.get("project_title") or raw.get("workspace_title") or None
+
+        mapping: dict = raw.get("mapping", {})
+        messages = _extract_messages(mapping, raw, conv_id)
+
+        return {
+            "id": conv_id,
+            "title": title,
+            "provider": "chatgpt",
+            "project": project,
+            "created_at": created_at,
+            "updated_at": updated_at,
+            "message_count": len(messages),
+            "messages": messages,
+        }
+
+
+# ---------------------------------------------------------------------------
+# Internal helpers
+# ---------------------------------------------------------------------------
+
+
+def _ts_to_iso(ts: float | int | str | None) -> str:
+    """Convert a Unix timestamp (float) or ISO string to ISO8601."""
+    if ts is None:
+        return ""
+    if isinstance(ts, (int, float)):
+        from datetime import datetime, timezone
+        return datetime.fromtimestamp(float(ts), tz=timezone.utc).isoformat()
+    return str(ts)
+
+
+def _extract_messages(
+    mapping: dict[str, Any], raw: dict, conv_id: str
+) -> list[dict]:
+    """Walk the ChatGPT conversation mapping tree to produce an ordered message list."""
+    if not mapping:
+        logger.warning("[chatgpt] Conversation %s has empty mapping", conv_id[:8])
+        return []
+
+    # Find the root node (the one that has no parent, or whose parent is None/not in mapping)
+    root_id = _find_root(mapping)
+    if root_id is None:
+        logger.warning(
+            "[chatgpt] Could not determine root node for conversation %s", conv_id[:8]
+        )
+        return []
+
+    messages: list[dict] = []
+    visited: set[str] = set()
+
+    def walk(node_id: str) -> None:
+        if node_id in visited:
+            return
+        visited.add(node_id)
+
+        node = mapping.get(node_id, {})
+        msg_data = node.get("message")
+
+        if msg_data:
+            role = msg_data.get("author", {}).get("role", "")
+            # Skip system/tool messages silently unless they have visible content
+            if role in ("user", "assistant"):
+                content_obj = msg_data.get("content", {})
+                content_type = content_obj.get("content_type", "text")
+                text = _extract_text(content_obj, conv_id, node_id)
+
+                if content_type != "text":
+                    logger.warning(
+                        "[chatgpt] Skipping %s content in conversation %s message %s "
+                        "— rich content not yet supported (see FUTURE.md)",
+                        content_type,
+                        conv_id[:8],
+                        node_id[:8],
+                    )
+                elif text:
+                    ts = msg_data.get("create_time")
+                    messages.append(
+                        {
+                            "role": role,
+                            "content": text,
+                            "content_type": "text",
+                            "timestamp": _ts_to_iso(ts) if ts else None,
+                        }
+                    )
+                else:
+                    logger.debug(
+                        "[chatgpt] Skipping empty message in conversation %s", conv_id[:8]
+                    )
+
+        # Walk children in order (ChatGPT typically has one child per node in a linear chat)
+        for child_id in node.get("children", []):
+            walk(child_id)
+
+    walk(root_id)
+    return messages
+
+
+def _find_root(mapping: dict[str, Any]) -> str | None:
+    """Find the root node ID — the node whose parent is absent or None."""
+    child_ids: set[str] = set()
+    for node in mapping.values():
+        for child in node.get("children", []):
+            child_ids.add(child)
+
+    for node_id in mapping:
+        if node_id not in child_ids:
+            return node_id
+
+    return None
+
+
+def _extract_text(content_obj: dict, conv_id: str, node_id: str) -> str:
+    """Extract plain text from a ChatGPT content object."""
+    parts = content_obj.get("parts", [])
+    if not parts:
+        return ""
+
+    text_parts = []
+    for part in parts:
+        if isinstance(part, str):
+            text_parts.append(part)
+        elif isinstance(part, dict):
+            # Could be an image or file reference — skip and warn
+            part_type = part.get("content_type", "unknown")
+            if part_type != "text":
+                logger.warning(
+                    "[chatgpt] Skipping %s attachment in conversation %s "
+                    "— rich content not yet supported (see FUTURE.md)",
+                    part_type,
+                    conv_id[:8],
+                )
+            else:
+                text_parts.append(part.get("text", ""))
+
+    return "\n".join(t for t in text_parts if t)
diff --git a/src/providers/claude.py b/src/providers/claude.py
new file mode 100644
index 0000000..54f0588
--- /dev/null
+++ b/src/providers/claude.py
@@ -0,0 +1,274 @@
+"""Claude provider — accesses claude.ai internal web API."""
+
+import logging
+import os
+
+from src.providers.base import BaseProvider, ProviderError
+
+logger = logging.getLogger(__name__)
+
+BASE_URL = "https://claude.ai/api"
+
+
+class ClaudeProvider(BaseProvider):
+    """Provider for Claude conversations via the internal web API.
+
+    Authentication: Cookie: sessionKey=<CLAUDE_SESSION_KEY>
+    Token: sessionKey cookie value from claude.ai.
+    Typical validity: ~30 days (opaque; expiry cannot be decoded client-side).
+    """
+
+    provider_name = "claude"
+
+    def __init__(self, session_key: str | None = None) -> None:
+        super().__init__()
+        key = session_key or os.getenv("CLAUDE_SESSION_KEY", "").strip()
+        if not key:
+            raise ProviderError(
+                self.provider_name,
+                "init",
+                RuntimeError(
+                    "CLAUDE_SESSION_KEY is not set. "
+                    "Run 'python -m src.main auth' to configure it."
+                ),
+            )
+        # Set cookie header; never log the key value
+        self._session.headers.update(
+            {
+                "Cookie": f"sessionKey={key}",
+                "Referer": "https://claude.ai/",
+                "Origin": "https://claude.ai",
+            }
+        )
+        self._org_id: str | None = None  # cached per session
+        logger.debug("[claude] Session initialised (key: [REDACTED])")
+
+    def _handle_401(self) -> None:
+        msg = (
+            "[claude] Authentication failed (401 Unauthorized). "
+            "Your sessionKey has likely expired (~30 day lifetime). "
+            "Note: Claude session keys are opaque — a 401 is the only expiry signal. "
+            "To refresh: open claude.ai in Chrome → F12 → Application → Cookies "
+            "→ find 'sessionKey' → copy the value. "
+            "Then run 'python -m src.main auth' or update CLAUDE_SESSION_KEY in .env."
+        )
+        logger.error(msg)
+        raise ProviderError(
+            self.provider_name,
+            "authentication",
+            RuntimeError("401 Unauthorized — Claude session key expired"),
+        )
+
+    def _get_org_id(self) -> str:
+        """Fetch and cache the organization ID (required for all Claude API calls)."""
+        if self._org_id:
+            return self._org_id
+
+        logger.debug("[claude] Bootstrapping: fetching organization ID")
+        url = f"{BASE_URL}/organizations"
+        try:
+            data = self._make_request("GET", url)
+        except ProviderError:
+            raise
+        except Exception as e:
+            raise ProviderError(self.provider_name, "get_org_id", e) from e
+
+        if not isinstance(data, list) or not data:
+            self._warn_unexpected_schema("get_org_id", "organizations array")
+            raise ProviderError(
+                self.provider_name,
+                "get_org_id",
+                RuntimeError("organizations endpoint returned empty or unexpected response"),
+            )
+
+        org = data[0]
+        org_id = org.get("uuid") or org.get("id")
+        if not org_id:
+            self._warn_unexpected_schema("get_org_id", "uuid/id")
+            raise ProviderError(
+                self.provider_name,
+                "get_org_id",
+                RuntimeError("Could not find organization ID in response"),
+            )
+
+        self._org_id = org_id
+        logger.debug("[claude] Got org_id: %s", org_id)
+        return org_id
+
+    def list_conversations(self, offset: int = 0, limit: int = 100) -> list[dict]:
+        """Fetch one page of conversations.
+
+        Claude's API may use cursor-based pagination. We attempt offset-based
+        first (via query param); if the response includes a ``next_cursor``
+        field, a WARNING is logged indicating manual investigation is needed.
+        """
+        org_id = self._get_org_id()
+        url = f"{BASE_URL}/organizations/{org_id}/chat_conversations"
+        params: dict = {"limit": limit}
+        if offset > 0:
+            params["offset"] = offset
+
+        try:
+            data = self._make_request("GET", url, params=params)
+        except ProviderError:
+            raise
+        except Exception as e:
+            raise ProviderError(self.provider_name, "list_conversations", e) from e
+
+        # Handle both list and dict responses
+        if isinstance(data, list):
+            conversations = data
+        elif isinstance(data, dict):
+            conversations = data.get("conversations") or data.get("chats") or []
+            if not conversations and data:
+                # Check for unexpected pagination mechanism
+                if "next_cursor" in data or "cursor" in data or "next" in data:
+                    logger.warning(
+                        "[claude] API returned cursor-based pagination — "
+                        "only first page will be fetched. "
+                        "Please report this at GitHub Issues."
+                    )
+        else:
+            self._warn_unexpected_schema("list_conversations", "root")
+            return []
+
+        return conversations
+
+    def get_conversation(self, conv_id: str) -> dict:
+        """Fetch full conversation detail for a single ID."""
+        org_id = self._get_org_id()
+        url = f"{BASE_URL}/organizations/{org_id}/chat_conversations/{conv_id}"
+        try:
+            data = self._make_request("GET", url)
+        except ProviderError:
+            raise
+        except Exception as e:
+            raise ProviderError(self.provider_name, "get_conversation", e) from e
+
+        if not isinstance(data, dict):
+            self._warn_unexpected_schema("get_conversation", "root")
+            return {}
+
+        return data
+
+    def normalize_conversation(self, raw: dict) -> dict:
+        """Transform Claude raw schema to the common normalized schema."""
+        conv_id = raw.get("uuid") or raw.get("id", "")
+        title = raw.get("name") or raw.get("title") or "Untitled"
+        created_at = raw.get("created_at") or raw.get("create_time") or ""
+        updated_at = raw.get("updated_at") or raw.get("update_time") or ""
+
+        # Project name — Claude may nest project info as project.name
+        project_data = raw.get("project") or {}
+        project: str | None = (
+            project_data.get("name")
+            if isinstance(project_data, dict)
+            else project_data
+        ) or None
+
+        # Messages
+        raw_messages = raw.get("chat_messages") or raw.get("messages") or []
+        messages = []
+
+        for msg in raw_messages:
+            role = _map_role(msg.get("sender") or msg.get("role", ""))
+            if not role:
+                continue
+
+            # Content can be a string or a list of content blocks
+            content_raw = msg.get("content") or msg.get("text") or ""
+            content, skipped_types = _extract_claude_text(content_raw, conv_id)
+
+            for ctype in skipped_types:
+                logger.warning(
+                    "[claude] Skipping %s content in conversation %s "
+                    "— rich content not yet supported (see FUTURE.md)",
+                    ctype,
+                    conv_id[:8],
+                )
+
+            timestamp = msg.get("created_at") or msg.get("timestamp") or None
+
+            if content is None:
+                logger.debug("[claude] Skipping empty message in conversation %s", conv_id[:8])
+                continue
+
+            messages.append(
+                {
+                    "role": role,
+                    "content": content,
+                    "content_type": "text",
+                    "timestamp": timestamp,
+                }
+            )
+
+        return {
+            "id": conv_id,
+            "title": title,
+            "provider": "claude",
+            "project": project,
+            "created_at": created_at,
+            "updated_at": updated_at,
+            "message_count": len(messages),
+            "messages": messages,
+        }
+
+
+# ---------------------------------------------------------------------------
+# Internal helpers
+# ---------------------------------------------------------------------------
+
+
+def _map_role(sender: str) -> str | None:
+    """Map Claude sender strings to normalized roles."""
+    mapping = {
+        "human": "user",
+        "user": "user",
+        "assistant": "assistant",
+        "claude": "assistant",
+        "ai": "assistant",
+        "system": "system",
+    }
+    return mapping.get(sender.lower()) if sender else None
+
+
+def _extract_claude_text(
+    content: str | list | dict, conv_id: str
+) -> tuple[str | None, list[str]]:
+    """Extract plain text from a Claude content field.
+
+    Returns:
+        (text_or_None, list_of_skipped_content_types)
+    """
+    skipped: list[str] = []
+
+    if isinstance(content, str):
+        text = content.strip()
+        return (text if text else None), skipped
+
+    if isinstance(content, list):
+        parts: list[str] = []
+        for block in content:
+            if isinstance(block, str):
+                parts.append(block)
+            elif isinstance(block, dict):
+                btype = block.get("type", "text")
+                if btype == "text":
+                    t = block.get("text", "").strip()
+                    if t:
+                        parts.append(t)
+                else:
+                    skipped.append(btype)
+        text = "\n".join(parts).strip()
+        return (text if text else None), skipped
+
+    if isinstance(content, dict):
+        btype = content.get("type", "text")
+        if btype == "text":
+            text = content.get("text", "").strip()
+            return (text if text else None), skipped
+        else:
+            skipped.append(btype)
+            return None, skipped
+
+    return None, skipped