diff --git a/src/main.el b/src/main.el
index e094698..2ff0b7f 100644
--- a/src/main.el
+++ b/src/main.el
@@ -804,6 +804,37 @@ fn handle_request(method: String, path: String, body: String) -> String {
         return "{\"url\":\"" + proj_url + "\",\"anon_key\":\"" + anon_key + "\"}"
     }
 
+    // ── Soul health diagnostic — surfaces raw signal from in-container soul ──
+    if str_eq(path, "/api/soul-health") {
+        if str_eq(method, "GET") {
+            let soul_base: String = state_get("__soul_url__")
+            // Probe 1: bare GET / — does ANYTHING listen?
+            let probe_root: String = http_get(soul_base + "/")
+            let probe_root_len: Int = str_len(probe_root)
+            // Probe 2: /healthz if soul has one
+            let probe_health: String = http_get(soul_base + "/healthz")
+            let probe_health_len: Int = str_len(probe_health)
+            // Probe 3: empty POST to /dharma/recv — does that route exist?
+            let probe_dharma_empty: String = http_post(soul_base + "/dharma/recv", "")
+            let probe_dharma_empty_len: Int = str_len(probe_dharma_empty)
+            // Probe 4: minimal valid envelope to /dharma/recv
+            let probe_envelope: String = "{\"channel\":\"health-probe\",\"from\":\"web-tier\",\"content\":\"{}\"}"
+            let probe_dharma: String = http_post(soul_base + "/dharma/recv", probe_envelope)
+            let probe_dharma_len: Int = str_len(probe_dharma)
+            // Escape body content for embedding in JSON response
+            let root_safe: String = str_replace(str_replace(probe_root, "\\", "\\\\"), "\"", "\\\"")
+            let health_safe: String = str_replace(str_replace(probe_health, "\\", "\\\\"), "\"", "\\\"")
+            let de_safe: String = str_replace(str_replace(probe_dharma_empty, "\\", "\\\\"), "\"", "\\\"")
+            let dharma_safe: String = str_replace(str_replace(probe_dharma, "\\", "\\\\"), "\"", "\\\"")
+            // Truncate via str_slice(s, 0, N); str_slice clamps end to len
+            let root_trunc: String = str_slice(root_safe, 0, 200)
+            let health_trunc: String = str_slice(health_safe, 0, 200)
+            let de_trunc: String = str_slice(de_safe, 0, 200)
+            let dharma_trunc: String = str_slice(dharma_safe, 0, 400)
+            return "{\"soul_url\":\"" + soul_base + "\",\"probe_root\":{\"len\":" + int_to_str(probe_root_len) + ",\"body_first_200\":\"" + root_trunc + "\"},\"probe_healthz\":{\"len\":" + int_to_str(probe_health_len) + ",\"body_first_200\":\"" + health_trunc + "\"},\"probe_dharma_empty\":{\"len\":" + int_to_str(probe_dharma_empty_len) + ",\"body_first_200\":\"" + de_trunc + "\"},\"probe_dharma_envelope\":{\"len\":" + int_to_str(probe_dharma_len) + ",\"body_first_400\":\"" + dharma_trunc + "\"}}"
+        }
+    }
+
     // ── Demo chat — proxies to the demo soul at 7772 ─────────────────────────
     if str_eq(path, "/api/demo") {
         if str_eq(method, "POST") {