diff --git a/AGENTS.md b/AGENTS.md
index 0a0a4d8..7e05a6b 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,7 +6,7 @@ Square Control is a couche 1 product (P40, workstation domain): a local, single-
 window layout tool for macOS. A pure Rust layout core decides frames; a Swift shell
 owns the hotkeys and the Accessibility calls. `project.v1.yaml` owns current state;
 `PROTOCOL.txt` owns the measurement protocol of the probes. Fleet doctrine comes from:
-https://raw.githubusercontent.com/libre-ai/project-governance/migrate/recover-code/docs/method/CONTEXT-TEMPLATE.md
+https://raw.githubusercontent.com/libre-ai/project-governance/HEAD/docs/method/CONTEXT-TEMPLATE.md
 
 ## Domain doctrine
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2e418a0..2c1a41c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,6 +1,6 @@
 # Contributing
 
-Square Control follows the [Libre AI contribution policy](https://github.com/libre-ai/project-governance/blob/migrate/recover-code/CONTRIBUTING.md).
+Square Control follows the [Libre AI contribution policy](https://github.com/libre-ai/project-governance/blob/HEAD/CONTRIBUTING.md).
 Every commit must satisfy the Developer Certificate of Origin with an author-matching
 `Signed-off-by` trailer. No Contributor License Agreement grants proprietary relicensing.
 
@@ -18,4 +18,4 @@ screenshots or personal data. Probe results are committed as produced, after the
 that governs them.
 
 Suspected vulnerabilities, exposed secrets and exploit details must never enter a public
-issue or pull request. Use the [private fleet security intake](https://github.com/libre-ai/project-governance/security/advisories/new).
+issue or pull request. Report them privately as [SECURITY.md](SECURITY.md) describes.
diff --git a/REUSE.toml b/REUSE.toml
index 4d53088..f028138 100644
--- a/REUSE.toml
+++ b/REUSE.toml
@@ -12,7 +12,7 @@ SPDX-License-Identifier = "EUPL-1.2"
 # Editorial documentation and first-party project records (LICENSING.md, "Documentation").
 # The probe protocol and the raw probe results are records of measurements, not executable specification.
 [[annotations]]
-path = ["README.md", "PROTOCOL.txt", "CONTRIBUTING.md", "probes/results/**"]
+path = ["README.md", "PROTOCOL.txt", "CONTRIBUTING.md", "SECURITY.md", "probes/results/**"]
 precedence = "override"
 SPDX-FileCopyrightText = "2026 Libre AI contributors"
 SPDX-License-Identifier = "CC-BY-4.0"
diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 0000000..e1f4c81
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,46 @@
+# Security policy
+
+Square Control is a local macOS window layout tool. It has no network service, no account,
+no telemetry and no model; its isolation boundary is the macOS user account. It acts on other
+applications' windows through the Accessibility API, under a per-user grant, and keeps a
+state file private to that user.
+
+## Supported versions
+
+Square Control is not released, not distributed and not signed for third parties. Security
+fixes target the default branch only; there is no release branch and no backport.
+
+## Reporting a vulnerability
+
+Do not put a suspected vulnerability, an exposed secret or exploit detail in a public issue
+or pull request.
+
+Report privately through GitHub private vulnerability reporting on this repository:
+
+<https://github.com/libre-ai/square-control/security/advisories/new>
+
+The fleet intake in `project-governance` reaches the same maintainer and may be used instead:
+
+<https://github.com/libre-ai/project-governance/security/advisories/new>
+
+Include the commit concerned, the macOS version and architecture, the impact, and a minimal
+reproduction. Remove window titles, screenshots, machine paths and any personal data from
+what you attach.
+
+There is no security mailing address, and this policy promises no response deadline.
+
+## Relevant findings
+
+In scope, for example:
+
+- a way for the tool to move, read or act on windows beyond the documented layout actions;
+- the release binary importing a symbol outside its closed list, declaring a URL scheme,
+  opening a network connection or carrying a machine path;
+- the state file becoming readable by another user, or carrying window titles or other
+  personal data;
+- a crafted window geometry or state file that makes the core or the shell crash, hang or
+  write outside its state file.
+
+The Accessibility grant itself is a macOS permission the user gives: a report that only
+restates what that grant allows any granted application to do is not a finding about
+Square Control.