diff --git a/docker/scripts/grok-cli-agent-entrypoint.sh b/docker/scripts/grok-cli-agent-entrypoint.sh
index 33ee3ddd..a9e7fe59 100755
--- a/docker/scripts/grok-cli-agent-entrypoint.sh
+++ b/docker/scripts/grok-cli-agent-entrypoint.sh
@@ -36,6 +36,10 @@ fi
 RUN_LOG="/tmp/grok-run.json"
 ERR_LOG="/tmp/grok-run.err"
 WORKSPACE="${ROBOCO_WORKSPACE:-$PWD}"
+# The role blueprint reaches grok as its system prompt via ~/.grok/AGENTS.md (a
+# global instruction file grok loads regardless of --cwd, verified live — the
+# `--system-prompt-override`/`--rules` flags are ignored in headless mode). The
+# render step above (grok_cli_config) wrote it from the mounted system prompt.
 # NOTE: grok generates its own session id and ignores a requested one (`-s` does
 # not pin it), so we do NOT pass a session id in; usage capture below reads the
 # real id back out of the JSON run log instead.
diff --git a/roboco/agent_sdk/grok_cli_session.py b/roboco/agent_sdk/grok_cli_session.py
index c2fcfdaf..b699140e 100644
--- a/roboco/agent_sdk/grok_cli_session.py
+++ b/roboco/agent_sdk/grok_cli_session.py
@@ -193,6 +193,9 @@ class GrokCliSession:  # pragma: no cover - needs the live grok binary
             *self._role_args,
             *self._extra_args,
         ]
+        # The role blueprint reaches grok as its system prompt via the global
+        # ~/.grok/AGENTS.md the main writes (not a per-turn flag — the headless
+        # --system-prompt-override is ignored).
         if self._session_id:
             argv += ["-r", self._session_id]
         return argv
diff --git a/roboco/agent_sdk/grok_intake_main.py b/roboco/agent_sdk/grok_intake_main.py
index 71b9ae8a..2e060180 100644
--- a/roboco/agent_sdk/grok_intake_main.py
+++ b/roboco/agent_sdk/grok_intake_main.py
@@ -28,7 +28,11 @@ from roboco.agent_sdk.intake_main import (
     make_message_source,
     make_relay_sink,
 )
-from roboco.llm.providers.grok_cli_config import GROK_CONFIG_PATH, render_config_toml
+from roboco.llm.providers.grok_cli_config import (
+    GROK_CONFIG_PATH,
+    render_config_toml,
+    write_agents_md,
+)
 
 if TYPE_CHECKING:
     from collections.abc import AsyncIterator
@@ -80,6 +84,8 @@ async def main() -> None:  # pragma: no cover - needs the live container + grok
     cwd = os.environ.get("ROBOCO_WORKSPACE", "/data/workspace")
 
     _render_grok_config(base_url, session_id)
+    # Install the role blueprint as grok's global system prompt (~/.grok/AGENTS.md).
+    write_agents_md()
 
     queue: asyncio.Queue[str | None] = asyncio.Queue()
     client = httpx.AsyncClient(timeout=30.0)
diff --git a/roboco/agent_sdk/grok_secretary_main.py b/roboco/agent_sdk/grok_secretary_main.py
index a4576fe5..e2d3aa4f 100644
--- a/roboco/agent_sdk/grok_secretary_main.py
+++ b/roboco/agent_sdk/grok_secretary_main.py
@@ -24,7 +24,11 @@ from roboco.agent_sdk.grok_cli_session import GrokCliSession
 from roboco.agent_sdk.intake_driver import IntakeDriver
 from roboco.agent_sdk.intake_main import build_receiver, make_message_source
 from roboco.agent_sdk.secretary_main import make_relay_sink
-from roboco.llm.providers.grok_cli_config import GROK_CONFIG_PATH, render_config_toml
+from roboco.llm.providers.grok_cli_config import (
+    GROK_CONFIG_PATH,
+    render_config_toml,
+    write_agents_md,
+)
 
 if TYPE_CHECKING:
     from collections.abc import AsyncIterator
@@ -78,6 +82,8 @@ async def main() -> None:  # pragma: no cover - needs the live container + grok
     cwd = os.environ.get("ROBOCO_WORKSPACE", "/app")
 
     _render_grok_config(base_url)
+    # Install the role blueprint as grok's global system prompt (~/.grok/AGENTS.md).
+    write_agents_md()
 
     queue: asyncio.Queue[str | None] = asyncio.Queue()
     client = httpx.AsyncClient(timeout=30.0)
diff --git a/roboco/llm/providers/grok_cli_config.py b/roboco/llm/providers/grok_cli_config.py
index 5beebae1..91251511 100644
--- a/roboco/llm/providers/grok_cli_config.py
+++ b/roboco/llm/providers/grok_cli_config.py
@@ -41,6 +41,16 @@ from roboco.services.gateway.role_config import get_role_config
 # grok reads its global config from ``$HOME/.grok/config.toml`` (the agent's HOME
 # is ``/home/agent``; the host ``auth.json`` is mounted alongside it).
 GROK_CONFIG_PATH = Path.home() / ".grok" / "config.toml"
+# grok loads ``$HOME/.grok/AGENTS.md`` as a GLOBAL instruction file regardless of
+# --cwd (verified live; the --system-prompt-override / --rules flags are ignored
+# in headless mode). This is how the RoboCo role blueprint becomes grok's system
+# prompt — the parity analogue of the Claude path's --system-prompt-file — without
+# writing into (and polluting) the agent's git workspace.
+GROK_AGENTS_PATH = Path.home() / ".grok" / "AGENTS.md"
+# The composed role blueprint the orchestrator mounts into every agent container.
+SYSTEM_PROMPT_PATH = Path(
+    os.environ.get("ROBOCO_SYSTEM_PROMPT", "/app/system-prompt.md")
+)
 # The entrypoint reads the computed flags (one token per line) from this file.
 GROK_ARGS_PATH = Path(os.environ.get("ROBOCO_GROK_ARGS_FILE", "/tmp/roboco-grok-args"))
 
@@ -178,8 +188,27 @@ def _load_mcp_config(path: str) -> dict[str, Any]:
         return {}
 
 
+def write_agents_md(
+    *, source: Path = SYSTEM_PROMPT_PATH, dest: Path = GROK_AGENTS_PATH
+) -> bool:
+    """Install the mounted role blueprint as grok's global system prompt.
+
+    Copies the composed prompt to ``~/.grok/AGENTS.md`` (the global instruction
+    file grok honours in headless mode). Best-effort: returns False and writes
+    nothing if the source is absent / unreadable, so a missing prompt never fails
+    the render.
+    """
+    try:
+        blueprint = source.read_text(encoding="utf-8")
+    except OSError:
+        return False
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    dest.write_text(blueprint, encoding="utf-8")
+    return True
+
+
 def main() -> int:
-    """Entrypoint: write ``~/.grok/config.toml`` + the per-role args file."""
+    """Entrypoint: write ``~/.grok/config.toml`` + AGENTS.md + the per-role args."""
     agent_id = os.environ.get("ROBOCO_AGENT_ID", "")
     mcp_path = os.environ.get("ROBOCO_MCP_CONFIG", "/app/mcp-config.json")
     try:
@@ -193,6 +222,7 @@ def main() -> int:
     GROK_CONFIG_PATH.write_text(
         render_config_toml(_load_mcp_config(mcp_path)), encoding="utf-8"
     )
+    write_agents_md()
     GROK_ARGS_PATH.write_text(
         "\n".join(grok_cli_args(agent_id, max_turns=max_turns)) + "\n", encoding="utf-8"
     )
diff --git a/tests/unit/llm/providers/test_grok_cli_config.py b/tests/unit/llm/providers/test_grok_cli_config.py
index d6a61ab9..9833468f 100644
--- a/tests/unit/llm/providers/test_grok_cli_config.py
+++ b/tests/unit/llm/providers/test_grok_cli_config.py
@@ -8,6 +8,8 @@ from typing import TYPE_CHECKING
 from roboco.llm.providers import grok_cli_config as gc
 
 if TYPE_CHECKING:
+    from pathlib import Path
+
     import pytest
 
 _SAMPLE_MCP = {
@@ -42,6 +44,20 @@ def test_render_config_toml_empty_when_no_servers() -> None:
     assert gc.render_config_toml({"mcpServers": {}}) == ""
 
 
+def test_write_agents_md_installs_the_blueprint(tmp_path: Path) -> None:
+    src = tmp_path / "system-prompt.md"
+    src.write_text("You are the RoboCo intake interviewer.", encoding="utf-8")
+    dest = tmp_path / ".grok" / "AGENTS.md"
+    assert gc.write_agents_md(source=src, dest=dest) is True
+    assert dest.read_text(encoding="utf-8") == "You are the RoboCo intake interviewer."
+
+
+def test_write_agents_md_noops_when_source_absent(tmp_path: Path) -> None:
+    dest = tmp_path / ".grok" / "AGENTS.md"
+    assert gc.write_agents_md(source=tmp_path / "absent.md", dest=dest) is False
+    assert not dest.exists()
+
+
 def test_developer_flags(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.delenv("ROBOCO_GROK_REASONING_EFFORT", raising=False)
     args = gc.grok_cli_args("be-dev-1")