docs(policy): linux-kpi mt76 C exemption (operator-approved 2026-08-04)

AGENTS.md

@@ -439,6 +439,29 @@ duplicate working code with zero functional gain, and the firmware expects `#[re
 packed)]` struct layouts that are most reliably defined in C headers matching the Linux
 source.
 
+### linux-kpi + redbear-mt76 exemption (operator-approved 2026-08-04)
+
+The mt76 C headers (mt76/Connac register and descriptor layouts, matching Linux
+`mt792x_regs.h` and the firmware headers byte-for-byte) and the bounded mt76 C transport
+layer in `redbear-mt7922` are an **exemption** to the Rust-only policy. This subsystem is
+a C-to-Redox driver shim that talks directly to MediaTek MT7922 (mt7921-family) Wi-Fi
+firmware via PCI WFDMA rings. The C headers are the firmware ABI contract. The C
+transport handles ONLY: WFDMA ring init, Connac TX/RX descriptor encode/decode, ROM-patch
+(`WIFI_MT7922_patch_mcu_1_1_hdr.bin`) section parsing + download, WM firmware
+(`WIFI_RAM_CODE_MT7922_1.bin`) transfer, MCU mailbox commands, and subsystem reset.
+
+**Architecture:** C headers = ABI contract (match Linux source 1:1). C transport =
+bounded firmware transport (no control logic). Rust = ALL driver logic: the
+SoftMAC/MLME control plane (scan/auth/assoc/key/regulatory/aggregation policy),
+lifecycle, driver-manager onboarding, netstack bridge, and the wifictl control surface.
+MT7922 is a mac80211 SoftMAC device — the MLME is implemented in Rust (shaped on
+mac80211 ops), never imported from Linux mac80211/cfg80211.
+
+This exemption mirrors the operator-approved linux-kpi + redbear-iwlwifi exemption
+(2026-07-24) and exists for the same reason: the firmware expects `#[repr(C, packed)]`
+struct layouts most reliably defined in C headers matching the Linux source, and the
+transport follows the proven bounded-C-transport pattern.
+
 ## DURABILITY POLICY
 
 Every change to an upstream-owned source tree (anything under `recipes/*/source/`) **must** be