diff --git a/src/timmy/thinking.py b/src/timmy/thinking.py
index d934803..f543f19 100644
--- a/src/timmy/thinking.py
+++ b/src/timmy/thinking.py
@@ -43,6 +43,7 @@ SEED_TYPES = (
     "freeform",
     "sovereignty",
     "observation",
+    "workspace",
 )
 
 # Existential reflection prompts — Timmy picks one at random
@@ -263,6 +264,9 @@ class ThinkingEngine:
         # Post-hook: file Gitea issues for actionable observations
         await self._maybe_file_issues()
 
+        # Post-hook: check workspace for new messages from Hermes
+        await self._check_workspace()
+
         # Post-hook: update MEMORY.md with latest reflection
         self._update_memory(thought)
 
@@ -616,6 +620,29 @@ class ThinkingEngine:
             logger.debug("Task queue query failed: %s", exc)
             pass
 
+        # Workspace updates (file-based communication with Hermes)
+        try:
+            from timmy.workspace import workspace_monitor
+
+            updates = workspace_monitor.get_pending_updates()
+            new_corr = updates.get("new_correspondence")
+            new_inbox = updates.get("new_inbox_files", [])
+
+            if new_corr:
+                # Count entries (assuming each entry starts with a timestamp or header)
+                line_count = len([l for l in new_corr.splitlines() if l.strip()])
+                parts.append(
+                    f"Workspace: {line_count} new correspondence entries (latest from: Hermes)"
+                )
+            if new_inbox:
+                files_str = ", ".join(new_inbox[:5])
+                if len(new_inbox) > 5:
+                    files_str += f", ... (+{len(new_inbox) - 5} more)"
+                parts.append(f"Workspace: {len(new_inbox)} new inbox files: {files_str}")
+        except Exception as exc:
+            logger.debug("Workspace check failed: %s", exc)
+            pass
+
         return "\n".join(parts) if parts else ""
 
     def _load_memory_context(self) -> str:
@@ -708,6 +735,8 @@ class ThinkingEngine:
             return seed_type, f"Sovereignty reflection: {prompt}"
         if seed_type == "observation":
             return seed_type, self._seed_from_observation()
+        if seed_type == "workspace":
+            return seed_type, self._seed_from_workspace()
         # freeform — minimal guidance to steer away from repetition
         return seed_type, "Free reflection — explore something you haven't thought about yet today."
 
@@ -778,6 +807,63 @@ class ThinkingEngine:
             logger.debug("Observation seed data unavailable: %s", exc)
         return "\n".join(context_parts)
 
+    def _seed_from_workspace(self) -> str:
+        """Gather workspace updates as thought seed.
+
+        When there are pending workspace updates, include them as context
+        for Timmy to reflect on. Falls back to random seed type if none.
+        """
+        try:
+            from timmy.workspace import workspace_monitor
+
+            updates = workspace_monitor.get_pending_updates()
+            new_corr = updates.get("new_correspondence")
+            new_inbox = updates.get("new_inbox_files", [])
+
+            if new_corr:
+                # Take first 200 chars of the new entry
+                snippet = new_corr[:200].replace("\n", " ")
+                if len(new_corr) > 200:
+                    snippet += "..."
+                return f"New workspace message from Hermes: {snippet}"
+
+            if new_inbox:
+                files_str = ", ".join(new_inbox[:3])
+                if len(new_inbox) > 3:
+                    files_str += f", ... (+{len(new_inbox) - 3} more)"
+                return f"New inbox files from Hermes: {files_str}"
+
+        except Exception as exc:
+            logger.debug("Workspace seed unavailable: %s", exc)
+
+        # Fall back to a random seed type if no workspace updates
+        return "The workspace is quiet. What should I be watching for?"
+
+    async def _check_workspace(self) -> None:
+        """Post-hook: check workspace for updates and mark them as seen.
+
+        This ensures Timmy 'processes' workspace updates even if the seed
+        was different, keeping the state file in sync.
+        """
+        try:
+            from timmy.workspace import workspace_monitor
+
+            updates = workspace_monitor.get_pending_updates()
+            new_corr = updates.get("new_correspondence")
+            new_inbox = updates.get("new_inbox_files", [])
+
+            if new_corr or new_inbox:
+                if new_corr:
+                    line_count = len([l for l in new_corr.splitlines() if l.strip()])
+                    logger.info("Workspace: processed %d new correspondence entries", line_count)
+                if new_inbox:
+                    logger.info("Workspace: processed %d new inbox files: %s", len(new_inbox), new_inbox)
+
+                # Mark as seen to update the state file
+                workspace_monitor.mark_seen()
+        except Exception as exc:
+            logger.debug("Workspace check failed: %s", exc)
+
     # Maximum retries when a generated thought is too similar to recent ones
     _MAX_DEDUP_RETRIES = 2
     # Similarity threshold (0.0 = completely different, 1.0 = identical)
diff --git a/src/timmy/workspace.py b/src/timmy/workspace.py
new file mode 100644
index 0000000..c9d0db9
--- /dev/null
+++ b/src/timmy/workspace.py
@@ -0,0 +1,140 @@
+"""Workspace monitor — tracks file-based communication between Hermes and Timmy.
+
+The workspace/ directory provides file-based communication:
+- workspace/correspondence.md — append-only journal
+- workspace/inbox/ — files from Hermes to Timmy
+- workspace/outbox/ — files from Timmy to Hermes
+
+This module tracks what Timmy has seen and detects new content.
+"""
+
+import json
+import logging
+from pathlib import Path
+
+from config import settings
+
+logger = logging.getLogger(__name__)
+
+_DEFAULT_STATE_PATH = Path("data/workspace_state.json")
+
+
+class WorkspaceMonitor:
+    """Monitors workspace/ directory for new correspondence and inbox files."""
+
+    def __init__(self, state_path: Path = _DEFAULT_STATE_PATH) -> None:
+        self._state_path = state_path
+        self._state: dict = {"last_correspondence_line": 0, "seen_inbox_files": []}
+        self._load_state()
+
+    def _get_workspace_path(self) -> Path:
+        """Get the workspace directory path."""
+        return Path(settings.repo_root) / "workspace"
+
+    def _load_state(self) -> None:
+        """Load persisted state from JSON file."""
+        try:
+            if self._state_path.exists():
+                with open(self._state_path, encoding="utf-8") as f:
+                    loaded = json.load(f)
+                    self._state = {
+                        "last_correspondence_line": loaded.get("last_correspondence_line", 0),
+                        "seen_inbox_files": loaded.get("seen_inbox_files", []),
+                    }
+        except Exception as exc:
+            logger.debug("Failed to load workspace state: %s", exc)
+            self._state = {"last_correspondence_line": 0, "seen_inbox_files": []}
+
+    def _save_state(self) -> None:
+        """Persist state to JSON file."""
+        try:
+            self._state_path.parent.mkdir(parents=True, exist_ok=True)
+            with open(self._state_path, "w", encoding="utf-8") as f:
+                json.dump(self._state, f, indent=2)
+        except Exception as exc:
+            logger.debug("Failed to save workspace state: %s", exc)
+
+    def check_correspondence(self) -> str | None:
+        """Read workspace/correspondence.md and return new entries.
+
+        Returns everything after the last seen line, or None if no new content.
+        """
+        try:
+            workspace = self._get_workspace_path()
+            correspondence_file = workspace / "correspondence.md"
+
+            if not correspondence_file.exists():
+                return None
+
+            content = correspondence_file.read_text(encoding="utf-8")
+            lines = content.splitlines()
+
+            last_seen = self._state.get("last_correspondence_line", 0)
+            if len(lines) <= last_seen:
+                return None
+
+            new_lines = lines[last_seen:]
+            return "\n".join(new_lines)
+        except Exception as exc:
+            logger.debug("Failed to check correspondence: %s", exc)
+            return None
+
+    def check_inbox(self) -> list[str]:
+        """List workspace/inbox/ files and return any not in seen list.
+
+        Returns a list of filenames that are new.
+        """
+        try:
+            workspace = self._get_workspace_path()
+            inbox_dir = workspace / "inbox"
+
+            if not inbox_dir.exists():
+                return []
+
+            seen = set(self._state.get("seen_inbox_files", []))
+            current_files = {f.name for f in inbox_dir.iterdir() if f.is_file()}
+            new_files = sorted(current_files - seen)
+
+            return new_files
+        except Exception as exc:
+            logger.debug("Failed to check inbox: %s", exc)
+            return []
+
+    def get_pending_updates(self) -> dict:
+        """Get all pending workspace updates.
+
+        Returns a dict with keys:
+        - 'new_correspondence': str or None — new entries from correspondence.md
+        - 'new_inbox_files': list[str] — new files in inbox/
+        """
+        return {
+            "new_correspondence": self.check_correspondence(),
+            "new_inbox_files": self.check_inbox(),
+        }
+
+    def mark_seen(self) -> None:
+        """Update state file after processing current content."""
+        try:
+            workspace = self._get_workspace_path()
+
+            # Update correspondence line count
+            correspondence_file = workspace / "correspondence.md"
+            if correspondence_file.exists():
+                content = correspondence_file.read_text(encoding="utf-8")
+                self._state["last_correspondence_line"] = len(content.splitlines())
+
+            # Update inbox seen list
+            inbox_dir = workspace / "inbox"
+            if inbox_dir.exists():
+                current_files = [f.name for f in inbox_dir.iterdir() if f.is_file()]
+                self._state["seen_inbox_files"] = sorted(current_files)
+            else:
+                self._state["seen_inbox_files"] = []
+
+            self._save_state()
+        except Exception as exc:
+            logger.debug("Failed to mark workspace as seen: %s", exc)
+
+
+# Module-level singleton
+workspace_monitor = WorkspaceMonitor()
diff --git a/tests/timmy/test_workspace.py b/tests/timmy/test_workspace.py
new file mode 100644
index 0000000..7951e37
--- /dev/null
+++ b/tests/timmy/test_workspace.py
@@ -0,0 +1,323 @@
+"""Tests for timmy.workspace — Workspace heartbeat monitoring."""
+
+import pytest
+
+from timmy.workspace import WorkspaceMonitor
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _make_monitor(tmp_path, monkeypatch):
+    """Create a WorkspaceMonitor with tmp_path as the repo_root."""
+    # Mock repo_root to use tmp_path
+    monkeypatch.setattr("timmy.workspace.settings", type("obj", (object,), {
+        "repo_root": str(tmp_path)
+    })())
+    
+    state_path = tmp_path / "workspace_state.json"
+    return WorkspaceMonitor(state_path=state_path)
+
+
+def _setup_workspace(tmp_path):
+    """Create the workspace directory structure."""
+    workspace = tmp_path / "workspace"
+    workspace.mkdir()
+    (workspace / "inbox").mkdir()
+    (workspace / "outbox").mkdir()
+    return workspace
+
+
+# ---------------------------------------------------------------------------
+# Basic monitoring
+# ---------------------------------------------------------------------------
+
+
+def test_no_updates_when_empty(tmp_path, monkeypatch):
+    """Fresh monitor with no workspace files should report no updates."""
+    # Don't create workspace dir — monitor should handle gracefully
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    
+    assert updates["new_correspondence"] is None
+    assert updates["new_inbox_files"] == []
+
+
+def test_detects_new_correspondence(tmp_path, monkeypatch):
+    """Writing to correspondence.md should be detected as new entries."""
+    workspace = _setup_workspace(tmp_path)
+    correspondence = workspace / "correspondence.md"
+    
+    # Pre-populate correspondence file
+    correspondence.write_text("Entry 1\nEntry 2\nEntry 3\n")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    # Should detect all 3 lines as new
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] == "Entry 1\nEntry 2\nEntry 3"
+    assert updates["new_inbox_files"] == []
+
+
+def test_detects_new_inbox_file(tmp_path, monkeypatch):
+    """Creating a file in inbox/ should be detected as new."""
+    workspace = _setup_workspace(tmp_path)
+    inbox = workspace / "inbox"
+    
+    # Create a file in inbox
+    (inbox / "message_1.md").write_text("Hello Timmy")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is None
+    assert updates["new_inbox_files"] == ["message_1.md"]
+
+
+def test_detects_multiple_inbox_files(tmp_path, monkeypatch):
+    """Multiple new inbox files should all be detected."""
+    workspace = _setup_workspace(tmp_path)
+    inbox = workspace / "inbox"
+    
+    # Create multiple files
+    (inbox / "message_2.md").write_text("Hello again")
+    (inbox / "task_1.md").write_text("Do something")
+    (inbox / "note.txt").write_text("A note")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_inbox_files"] == ["message_2.md", "note.txt", "task_1.md"]
+
+
+def test_detects_both_correspondence_and_inbox(tmp_path, monkeypatch):
+    """Monitor should detect both correspondence and inbox updates together."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("New journal entry\n")
+    
+    inbox = workspace / "inbox"
+    (inbox / "urgent.md").write_text("Urgent message")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] == "New journal entry"
+    assert updates["new_inbox_files"] == ["urgent.md"]
+
+
+# ---------------------------------------------------------------------------
+# Marking as seen
+# ---------------------------------------------------------------------------
+
+
+def test_mark_seen_clears_pending(tmp_path, monkeypatch):
+    """After mark_seen, get_pending_updates should return empty."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("Line 1\nLine 2\n")
+    
+    inbox = workspace / "inbox"
+    (inbox / "file.md").write_text("Content")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    # First check — should have updates
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is not None
+    assert len(updates["new_inbox_files"]) == 1
+    
+    # Mark as seen
+    monitor.mark_seen()
+    
+    # Second check — should be empty
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is None
+    assert updates["new_inbox_files"] == []
+
+
+def test_mark_seen_persists_line_count(tmp_path, monkeypatch):
+    """mark_seen should remember how many lines we've seen."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("Line 1\nLine 2\nLine 3\n")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    monitor.mark_seen()
+    
+    # Add more lines
+    correspondence.write_text("Line 1\nLine 2\nLine 3\nLine 4\nLine 5\n")
+    
+    # Should only see the new lines
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] == "Line 4\nLine 5"
+
+
+# ---------------------------------------------------------------------------
+# State persistence
+# ---------------------------------------------------------------------------
+
+
+def test_state_persists_across_instances(tmp_path, monkeypatch):
+    """State should be saved and loaded when creating a new monitor instance."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("First entry\n")
+    
+    inbox = workspace / "inbox"
+    (inbox / "first.md").write_text("First")
+    
+    # First monitor instance
+    monitor1 = _make_monitor(tmp_path, monkeypatch)
+    monitor1.mark_seen()
+    
+    # Add new content
+    correspondence.write_text("First entry\nSecond entry\n")
+    (inbox / "second.md").write_text("Second")
+    
+    # Second monitor instance (should load state from file)
+    monitor2 = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor2.get_pending_updates()
+    assert updates["new_correspondence"] == "Second entry"
+    assert updates["new_inbox_files"] == ["second.md"]
+
+
+def test_state_survives_missing_files(tmp_path, monkeypatch):
+    """Monitor should handle missing correspondence file gracefully."""
+    workspace = _setup_workspace(tmp_path)
+    
+    # Create and mark as seen
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("Entry\n")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    monitor.mark_seen()
+    
+    # Delete the file
+    correspondence.unlink()
+    
+    # Should return None gracefully
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is None
+
+
+# ---------------------------------------------------------------------------
+# Edge cases
+# ---------------------------------------------------------------------------
+
+
+def test_empty_correspondence_file(tmp_path, monkeypatch):
+    """Empty correspondence file should return None."""
+    workspace = _setup_workspace(tmp_path)
+    (workspace / "correspondence.md").write_text("")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is None
+
+
+def test_empty_inbox_dir(tmp_path, monkeypatch):
+    """Empty inbox directory should return empty list."""
+    _setup_workspace(tmp_path)
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_inbox_files"] == []
+
+
+def test_missing_inbox_dir(tmp_path, monkeypatch):
+    """Missing inbox directory should return empty list."""
+    workspace = tmp_path / "workspace"
+    workspace.mkdir()
+    # No inbox subdir
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_inbox_files"] == []
+
+
+def test_missing_workspace_dir(tmp_path, monkeypatch):
+    """Missing workspace directory should return empty results."""
+    # No workspace dir at all
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] is None
+    assert updates["new_inbox_files"] == []
+
+
+def test_correspondence_with_blank_lines(tmp_path, monkeypatch):
+    """Correspondence with blank lines should be handled correctly."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("Entry 1\n\nEntry 2\n\n\nEntry 3\n")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] == "Entry 1\n\nEntry 2\n\n\nEntry 3"
+
+
+def test_inbox_ignores_subdirectories(tmp_path, monkeypatch):
+    """Inbox should only list files, not subdirectories."""
+    workspace = _setup_workspace(tmp_path)
+    inbox = workspace / "inbox"
+    
+    (inbox / "file.md").write_text("Content")
+    (inbox / "subdir").mkdir()
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    
+    updates = monitor.get_pending_updates()
+    assert updates["new_inbox_files"] == ["file.md"]
+
+
+def test_deleted_inbox_files_removed_from_state(tmp_path, monkeypatch):
+    """When inbox files are deleted, they should be removed from seen list."""
+    workspace = _setup_workspace(tmp_path)
+    inbox = workspace / "inbox"
+    
+    # Create and see a file
+    (inbox / "temp.md").write_text("Temp")
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    monitor.mark_seen()
+    
+    # Delete the file
+    (inbox / "temp.md").unlink()
+    
+    # mark_seen should update seen list to remove deleted files
+    monitor.mark_seen()
+    
+    # State should now have empty seen list
+    assert monitor._state["seen_inbox_files"] == []
+
+
+def test_correspondence_append_only(tmp_path, monkeypatch):
+    """Correspondence is append-only; modifying existing content doesn't re-notify."""
+    workspace = _setup_workspace(tmp_path)
+    
+    correspondence = workspace / "correspondence.md"
+    correspondence.write_text("Line 1\nLine 2\n")
+    
+    monitor = _make_monitor(tmp_path, monkeypatch)
+    monitor.mark_seen()
+    
+    # Modify the file (truncate and rewrite) — this resets line count
+    # but correspondence.md should be append-only in practice
+    correspondence.write_text("Modified Line 1\nModified Line 2\nLine 3\n")
+    
+    # Line 3 is the only truly new line (we've now seen 2, file has 3)
+    updates = monitor.get_pending_updates()
+    assert updates["new_correspondence"] == "Line 3"