diff --git a/workspace/claude_sdk_executor.py b/workspace/claude_sdk_executor.py
index 8f8ce7e8..f702eef5 100644
--- a/workspace/claude_sdk_executor.py
+++ b/workspace/claude_sdk_executor.py
@@ -50,6 +50,7 @@ from executor_helpers import (
     commit_memory,
     extract_message_text,
     get_a2a_instructions,
+    get_hma_instructions,
     get_mcp_server_path,
     get_system_prompt,
     read_delegation_results,
@@ -211,12 +212,12 @@ class ClaudeSDKExecutor(AgentExecutor):
         return CONFIG_MOUNT
 
     def _build_system_prompt(self) -> str | None:
-        """Compose system prompt from file + A2A delegation instructions."""
+        """Compose system prompt from file + A2A + HMA memory instructions."""
         base = get_system_prompt(self.config_path, fallback=self.system_prompt)
         a2a = get_a2a_instructions(mcp=True)
-        if base and a2a:
-            return f"{base}\n\n{a2a}"
-        return base or a2a
+        hma = get_hma_instructions()
+        parts = [p for p in (base, a2a, hma) if p]
+        return "\n\n".join(parts) if parts else None
 
     def _prepare_prompt(self, user_input: str) -> str:
         """Prepend delegation results that arrived while idle."""
diff --git a/workspace/executor_helpers.py b/workspace/executor_helpers.py
index 5bc50c90..0d6e2d85 100644
--- a/workspace/executor_helpers.py
+++ b/workspace/executor_helpers.py
@@ -290,6 +290,31 @@ def get_a2a_instructions(mcp: bool = True) -> str:
     return _A2A_INSTRUCTIONS_MCP if mcp else _A2A_INSTRUCTIONS_CLI
 
 
+_HMA_INSTRUCTIONS = """## Hierarchical Memory (HMA)
+You have persistent memory tools that survive across sessions and restarts:
+
+- **commit_memory(content, scope)**: Save important information.
+  - LOCAL: private to you only (default)
+  - TEAM: shared with your parent workspace and siblings (same team)
+  - GLOBAL: shared with the entire org (only root workspaces can write)
+
+- **recall_memory(query)**: Search your accessible memories. Returns LOCAL + TEAM + GLOBAL matches.
+
+**When to use memory:**
+- After making a decision or learning something non-obvious → commit_memory("decision X because Y", scope="TEAM")
+- Before starting work → recall_memory("what did the team decide about X")
+- When you discover org-wide knowledge (repo locations, API patterns, conventions) → commit_memory(fact, scope="GLOBAL") if you are a root workspace, or scope="TEAM" to share with your team
+- After completing a task → commit_memory("completed task X, PR #N opened", scope="TEAM") so your lead and teammates know
+
+**Memory is automatically recalled** at the start of each new session. Use it proactively during work to share context.
+"""
+
+
+def get_hma_instructions() -> str:
+    """Return HMA memory instructions for system-prompt injection."""
+    return _HMA_INSTRUCTIONS
+
+
 # ========================================================================
 # Misc text helpers
 # ========================================================================
diff --git a/workspace/tests/test_claude_sdk_executor.py b/workspace/tests/test_claude_sdk_executor.py
index e3781ad9..ac3b0c3d 100644
--- a/workspace/tests/test_claude_sdk_executor.py
+++ b/workspace/tests/test_claude_sdk_executor.py
@@ -479,7 +479,8 @@ def test_build_system_prompt_combines_base_and_a2a_via_fixture():
     """Direct test bypassing the execute() path."""
     e = _make_executor()
     with patch("claude_sdk_executor.get_system_prompt", return_value="BASE"), \
-         patch("claude_sdk_executor.get_a2a_instructions", return_value="A2A"):
+         patch("claude_sdk_executor.get_a2a_instructions", return_value="A2A"), \
+         patch("claude_sdk_executor.get_hma_instructions", return_value=""):
         out = e._build_system_prompt()
     assert out == "BASE\n\nA2A"
 
@@ -487,17 +488,31 @@ def test_build_system_prompt_combines_base_and_a2a_via_fixture():
 def test_build_system_prompt_base_only():
     e = _make_executor()
     with patch("claude_sdk_executor.get_system_prompt", return_value="BASE"), \
-         patch("claude_sdk_executor.get_a2a_instructions", return_value=""):
+         patch("claude_sdk_executor.get_a2a_instructions", return_value=""), \
+         patch("claude_sdk_executor.get_hma_instructions", return_value=""):
         assert e._build_system_prompt() == "BASE"
 
 
 def test_build_system_prompt_a2a_only():
     e = _make_executor()
     with patch("claude_sdk_executor.get_system_prompt", return_value=None), \
-         patch("claude_sdk_executor.get_a2a_instructions", return_value="A2A"):
+         patch("claude_sdk_executor.get_a2a_instructions", return_value="A2A"), \
+         patch("claude_sdk_executor.get_hma_instructions", return_value=""):
         assert e._build_system_prompt() == "A2A"
 
 
+def test_build_system_prompt_includes_hma():
+    """HMA instructions are appended when present."""
+    e = _make_executor()
+    with patch("claude_sdk_executor.get_system_prompt", return_value="BASE"), \
+         patch("claude_sdk_executor.get_a2a_instructions", return_value="A2A"), \
+         patch("claude_sdk_executor.get_hma_instructions", return_value="## Hierarchical Memory"):
+        out = e._build_system_prompt()
+    assert "BASE" in out
+    assert "A2A" in out
+    assert "## Hierarchical Memory" in out
+
+
 def test_prepare_prompt_no_delegation_returns_unchanged():
     e = _make_executor()
     with patch("claude_sdk_executor.read_delegation_results", return_value=""):