diff --git a/v2/crates/wifi-densepose-bfld/src/ha_discovery.rs b/v2/crates/wifi-densepose-bfld/src/ha_discovery.rs
new file mode 100644
index 00000000..1f4881d8
--- /dev/null
+++ b/v2/crates/wifi-densepose-bfld/src/ha_discovery.rs
@@ -0,0 +1,160 @@
+//! Home Assistant MQTT auto-discovery payload publisher. ADR-122 §2.1.
+//!
+//! Generates the JSON config messages HA expects on
+//! `homeassistant/<type>/<unique_id>/config` to auto-create the six BFLD
+//! entities. Class-gated identically to the state-topic router
+//! (`mqtt_topics.rs`): `identity_risk` discovery is only published at exactly
+//! `PrivacyClass::Anonymous`.
+//!
+//! Discovery payloads should be published **once per node session**, retained
+//! by the broker (`retain = true`) so HA finds them on next start. The
+//! `RumqttPublisher` exposes a `with_retain(true)` builder for this; the
+//! state-topic loop must keep `retain = false` to avoid stale-state flapping.
+
+#![cfg(feature = "std")]
+
+use crate::mqtt_topics::TopicMessage;
+use crate::PrivacyClass;
+
+/// Render every HA-DISCO config message for the given node at `class`. Returns
+/// an empty `Vec` for classes < `Anonymous` (HA doesn't see raw / derived).
+#[must_use]
+pub fn render_discovery_payloads(node_id: &str, class: PrivacyClass) -> Vec<TopicMessage> {
+    if class.as_u8() < PrivacyClass::Anonymous.as_u8() {
+        return Vec::new();
+    }
+
+    let mut out = Vec::with_capacity(6);
+
+    out.push(config_message(
+        "binary_sensor",
+        node_id,
+        "presence",
+        "BFLD Presence",
+        Some("occupancy"),
+        None,
+        None,
+    ));
+    out.push(config_message(
+        "sensor",
+        node_id,
+        "motion",
+        "BFLD Motion",
+        None,
+        None,
+        Some("diagnostic"),
+    ));
+    out.push(config_message(
+        "sensor",
+        node_id,
+        "person_count",
+        "BFLD Person Count",
+        None,
+        Some("people"),
+        None,
+    ));
+    out.push(config_message(
+        "sensor",
+        node_id,
+        "zone_activity",
+        "BFLD Zone Activity",
+        None,
+        None,
+        Some("diagnostic"),
+    ));
+    out.push(config_message(
+        "sensor",
+        node_id,
+        "confidence",
+        "BFLD Confidence",
+        None,
+        None,
+        Some("diagnostic"),
+    ));
+
+    // identity_risk discovery only at class 2. Class 3 computes but doesn't
+    // publish — therefore HA should not even see the entity exist.
+    if class == PrivacyClass::Anonymous {
+        out.push(config_message(
+            "sensor",
+            node_id,
+            "identity_risk",
+            "BFLD Identity Risk",
+            None,
+            None,
+            Some("diagnostic"),
+        ));
+    }
+
+    out
+}
+
+fn config_message(
+    ha_type: &str,
+    node_id: &str,
+    entity: &str,
+    name: &str,
+    device_class: Option<&str>,
+    unit_of_measurement: Option<&str>,
+    entity_category: Option<&str>,
+) -> TopicMessage {
+    let unique_id = format!("{node_id}_bfld_{entity}");
+    let topic = format!("homeassistant/{ha_type}/{unique_id}/config");
+    let state_topic = format!("ruview/{node_id}/bfld/{entity}/state");
+
+    let mut payload = String::with_capacity(256);
+    payload.push('{');
+    push_str_field(&mut payload, "name", name, true);
+    push_str_field(&mut payload, "unique_id", &unique_id, false);
+    push_str_field(&mut payload, "state_topic", &state_topic, false);
+    if let Some(dc) = device_class {
+        push_str_field(&mut payload, "device_class", dc, false);
+    }
+    if let Some(unit) = unit_of_measurement {
+        push_str_field(&mut payload, "unit_of_measurement", unit, false);
+    }
+    if let Some(cat) = entity_category {
+        push_str_field(&mut payload, "entity_category", cat, false);
+    }
+    payload.push_str(",\"device\":{");
+    push_str_field(&mut payload, "identifiers", node_id, true);
+    push_str_field(
+        &mut payload,
+        "name",
+        &format!("RuView Seed {node_id}"),
+        false,
+    );
+    push_str_field(&mut payload, "model", "BFLD", false);
+    push_str_field(&mut payload, "manufacturer", "RuView", false);
+    payload.push('}');
+    payload.push('}');
+
+    TopicMessage { topic, payload }
+}
+
+fn push_str_field(out: &mut String, key: &str, value: &str, first: bool) {
+    if !first {
+        out.push(',');
+    }
+    out.push('"');
+    out.push_str(key);
+    out.push_str("\":\"");
+    // Minimal JSON escaping for the values BFLD controls — node_id is ASCII
+    // alphanumeric + dash by convention, names are operator-controlled. A
+    // future iter can swap to serde_json::to_string for full escape coverage.
+    for ch in value.chars() {
+        match ch {
+            '"' => out.push_str("\\\""),
+            '\\' => out.push_str("\\\\"),
+            '\n' => out.push_str("\\n"),
+            '\r' => out.push_str("\\r"),
+            '\t' => out.push_str("\\t"),
+            c if (c as u32) < 0x20 => {
+                let escape = format!("\\u{:04x}", c as u32);
+                out.push_str(&escape);
+            }
+            c => out.push(c),
+        }
+    }
+    out.push('"');
+}
diff --git a/v2/crates/wifi-densepose-bfld/src/lib.rs b/v2/crates/wifi-densepose-bfld/src/lib.rs
index 4a593cd1..ba1d9cc8 100644
--- a/v2/crates/wifi-densepose-bfld/src/lib.rs
+++ b/v2/crates/wifi-densepose-bfld/src/lib.rs
@@ -22,6 +22,8 @@ pub mod emitter;
 pub mod event;
 pub mod frame;
 #[cfg(feature = "std")]
+pub mod ha_discovery;
+#[cfg(feature = "std")]
 pub mod mqtt_topics;
 #[cfg(feature = "std")]
 pub mod identity_features;
@@ -45,6 +47,8 @@ pub use emitter::{BfldEmitter, SensingInputs};
 #[cfg(feature = "std")]
 pub use event::BfldEvent;
 #[cfg(feature = "std")]
+pub use ha_discovery::render_discovery_payloads;
+#[cfg(feature = "std")]
 pub use mqtt_topics::{publish_event, render_events, CapturePublisher, Publish, TopicMessage};
 #[cfg(feature = "mqtt")]
 pub use rumqttc_publisher::RumqttPublisher;
diff --git a/v2/crates/wifi-densepose-bfld/tests/ha_discovery.rs b/v2/crates/wifi-densepose-bfld/tests/ha_discovery.rs
new file mode 100644
index 00000000..9563757f
--- /dev/null
+++ b/v2/crates/wifi-densepose-bfld/tests/ha_discovery.rs
@@ -0,0 +1,129 @@
+//! Acceptance tests for ADR-122 §2.1 — HA auto-discovery payloads.
+
+#![cfg(feature = "std")]
+
+use wifi_densepose_bfld::{render_discovery_payloads, PrivacyClass};
+
+fn topics(class: PrivacyClass) -> Vec<String> {
+    render_discovery_payloads("seed-01", class)
+        .into_iter()
+        .map(|m| m.topic)
+        .collect()
+}
+
+#[test]
+fn raw_and_derived_classes_produce_no_discovery_payloads() {
+    for class in [PrivacyClass::Raw, PrivacyClass::Derived] {
+        assert!(
+            render_discovery_payloads("seed-01", class).is_empty(),
+            "class {class:?} must not emit HA discovery",
+        );
+    }
+}
+
+#[test]
+fn anonymous_class_produces_six_discovery_payloads() {
+    let ts = topics(PrivacyClass::Anonymous);
+    assert_eq!(ts.len(), 6);
+}
+
+#[test]
+fn restricted_class_omits_identity_risk_discovery() {
+    let ts = topics(PrivacyClass::Restricted);
+    assert_eq!(ts.len(), 5, "Restricted: 5 entities, no identity_risk");
+    assert!(
+        !ts.iter().any(|t| t.contains("identity_risk")),
+        "Restricted must not advertise identity_risk entity to HA",
+    );
+}
+
+#[test]
+fn discovery_topic_format_matches_ha_convention() {
+    let ts = topics(PrivacyClass::Anonymous);
+    assert!(ts.contains(&"homeassistant/binary_sensor/seed-01_bfld_presence/config".into()));
+    assert!(ts.contains(&"homeassistant/sensor/seed-01_bfld_motion/config".into()));
+    assert!(ts.contains(&"homeassistant/sensor/seed-01_bfld_person_count/config".into()));
+    assert!(ts.contains(&"homeassistant/sensor/seed-01_bfld_zone_activity/config".into()));
+    assert!(ts.contains(&"homeassistant/sensor/seed-01_bfld_confidence/config".into()));
+    assert!(ts.contains(&"homeassistant/sensor/seed-01_bfld_identity_risk/config".into()));
+}
+
+#[test]
+fn presence_payload_carries_occupancy_device_class() {
+    let msgs = render_discovery_payloads("seed-01", PrivacyClass::Anonymous);
+    let pres = msgs
+        .iter()
+        .find(|m| m.topic.contains("presence"))
+        .expect("presence config");
+    assert!(pres.payload.contains("\"device_class\":\"occupancy\""));
+}
+
+#[test]
+fn motion_payload_marked_as_diagnostic() {
+    let msgs = render_discovery_payloads("seed-01", PrivacyClass::Anonymous);
+    let motion = msgs
+        .iter()
+        .find(|m| m.topic.contains("motion"))
+        .expect("motion config");
+    assert!(motion.payload.contains("\"entity_category\":\"diagnostic\""));
+}
+
+#[test]
+fn person_count_payload_carries_unit_of_measurement() {
+    let msgs = render_discovery_payloads("seed-01", PrivacyClass::Anonymous);
+    let pc = msgs
+        .iter()
+        .find(|m| m.topic.contains("person_count"))
+        .expect("person_count config");
+    assert!(pc.payload.contains("\"unit_of_measurement\":\"people\""));
+}
+
+#[test]
+fn every_payload_contains_unique_id_and_state_topic_pointing_at_correct_state_topic() {
+    let msgs = render_discovery_payloads("seed-99", PrivacyClass::Anonymous);
+    for msg in &msgs {
+        // unique_id is required for HA to dedupe entity creation.
+        assert!(
+            msg.payload.contains("\"unique_id\":\""),
+            "missing unique_id in {msg:?}",
+        );
+        // state_topic must point back at the BFLD `ruview/<node>/bfld/<entity>/state` path.
+        assert!(
+            msg.payload.contains("\"state_topic\":\"ruview/seed-99/bfld/"),
+            "state_topic wrong in {msg:?}",
+        );
+        // Device block ties all six entities to one HA device.
+        assert!(msg.payload.contains("\"device\":{"));
+        assert!(msg.payload.contains("\"identifiers\":\"seed-99\""));
+        assert!(msg.payload.contains("\"manufacturer\":\"RuView\""));
+    }
+}
+
+#[test]
+fn unique_id_matches_topic_segment() {
+    let msgs = render_discovery_payloads("seed-01", PrivacyClass::Anonymous);
+    for msg in &msgs {
+        // topic is homeassistant/<type>/<unique_id>/config — the unique_id segment
+        // must appear in the payload too.
+        let parts: Vec<&str> = msg.topic.split('/').collect();
+        assert_eq!(parts.len(), 4, "topic shape wrong: {}", msg.topic);
+        assert_eq!(parts[0], "homeassistant");
+        assert_eq!(parts[3], "config");
+        let unique_id_from_topic = parts[2];
+        let needle = format!("\"unique_id\":\"{unique_id_from_topic}\"");
+        assert!(
+            msg.payload.contains(&needle),
+            "unique_id mismatch between topic and payload: {msg:?}",
+        );
+    }
+}
+
+#[test]
+fn class_2_discovery_includes_identity_risk_explicitly() {
+    let msgs = render_discovery_payloads("seed-01", PrivacyClass::Anonymous);
+    let risk = msgs
+        .iter()
+        .find(|m| m.topic.contains("identity_risk"))
+        .expect("identity_risk config must be present at class 2");
+    assert!(risk.payload.contains("\"entity_category\":\"diagnostic\""));
+}