diff --git a/src/amplifier_app_opencode/prereqs.py b/src/amplifier_app_opencode/prereqs.py
index f6ea9b1..50735e4 100644
--- a/src/amplifier_app_opencode/prereqs.py
+++ b/src/amplifier_app_opencode/prereqs.py
@@ -52,20 +52,27 @@
 OPENCODE_INSTALL_SH = "https://opencode.ai/install"
 OPENCODE_NPM_PACKAGE = "opencode-ai"
 
-# Minimum amplifier-agent version amplifier-opencode requires. >= 0.12.0 is the
-# first version whose HTTP face honours `provider.config` from the host config
-# we pass via `--host-config`. Below it, `serve` accepted the file but dropped
-# that block on every turn, so `--host-config` silently did less than it does
-# under `run` -- and `debug.rawLlmPayloads` is rejected outright as an unknown
-# key. Since we document `--host-config` as the way to configure the engine, the
-# floor has to be the version where it actually applies.
-# (0.11.0 remains the floor for namespaced reseller model ids
-# (`github-copilot/<model>`), without which Copilot's `claude-sonnet-5` collides
-# with the native anthropic provider's; 0.10.0 for `GET /v1/skills` and
-# `GET /v1/modes`, which the skills and modes bridges read; 0.9.3 for
-# `auth set --stdin`, which onboarding uses to hand the provider key to the
-# agent off-argv. 0.12.0 subsumes all three.)
-MIN_AGENT_VERSION = "0.12.0"
+# Minimum amplifier-agent version amplifier-opencode requires. >= 0.14.0 is the
+# first version whose `serve` lifecycle is correct on Windows. We drive `serve`
+# for every turn, and below it three POSIX assumptions were wrong there. The
+# damaging one: `os.kill(pid, 0)` was used as a benign liveness probe, but on
+# Windows CPython maps `CTRL_C_EVENT` to `GenerateConsoleCtrlEvent`, and since
+# `CTRL_C_EVENT == 0`, signal 0 delivers a real console Ctrl+C to the target's
+# process group -- so `serve status` could interrupt the very server it was
+# reporting on. `signal.SIGKILL` also does not exist on Windows and raised
+# `AttributeError` when escalating a stop, and `start_new_session=True` is a
+# POSIX-only way to detach a restart. 0.14.0 additionally stops refusing to
+# write `serve.json` on Windows, where the 0600/0700 permission verification
+# could never pass against NTFS.
+# (0.12.0 remains the floor for `provider.config` being honoured from the host
+# config we pass via `--host-config`, without which `serve` dropped that block
+# on every turn and `debug.rawLlmPayloads` was rejected as an unknown key;
+# 0.11.0 for namespaced reseller model ids (`github-copilot/<model>`), without
+# which Copilot's `claude-sonnet-5` collides with the native anthropic
+# provider's; 0.10.0 for `GET /v1/skills` and `GET /v1/modes`, which the skills
+# and modes bridges read; 0.9.3 for `auth set --stdin`, which onboarding uses to
+# hand the provider key to the agent off-argv. 0.14.0 subsumes all four.)
+MIN_AGENT_VERSION = "0.14.0"
 # The silent, launch-time auto-install/self-heal targets this exact known-good
 # git tag rather than a moving branch, so a reliability tool never drags users
 # onto un-vetted ``main``. Kept in lockstep with MIN_AGENT_VERSION: to adopt a
diff --git a/tests/e2e/suites/onboarding/conftest.py b/tests/e2e/suites/onboarding/conftest.py
index de52f24..18a5157 100644
--- a/tests/e2e/suites/onboarding/conftest.py
+++ b/tests/e2e/suites/onboarding/conftest.py
@@ -57,7 +57,7 @@
 SENTINEL = "sk-e2e-SENTINEL-DO-NOT-LEAK-abc123"
 
 # Version the fake agent reports for ``--version``. Comfortably above
-# ``prereqs.MIN_AGENT_VERSION`` (0.12.0 as of this writing) so the preflight's
+# ``prereqs.MIN_AGENT_VERSION`` (0.14.0 as of this writing) so the preflight's
 # version-floor check passes without this suite needing to track that constant.
 FAKE_AGENT_VERSION = "99.0.0"