diff --git a/TODO.AI.md b/TODO.AI.md
index 4933d10..3c42d90 100644
--- a/TODO.AI.md
+++ b/TODO.AI.md
@@ -7,6 +7,18 @@
   and the container exits 1 (empty days value passed to `openssl req -days`). The file is
   generated, so the fix belongs in the upstream gen-dockerfile template, then regenerate.
 
+## Fixed — existing runners kept a stale server address and could not reach Gitea (start-runners)
+
+- `act_runner register` stores the server address in each `reg/runner-N/.runner`, and `start-runners`
+  skips registration when that file exists. Runners registered before the `127.0.0.1` default (when it
+  was the container IP) kept e.g. `http://172.17.0.3:80`; after a restart that IP no longer belongs to
+  Gitea, so every `Declare` call hung until the 60s client timeout (`deadline_exceeded`).
+- `start-runners` now rewrites `address` in each existing `.runner` to the current `SERVER_ADDRESS` on
+  every start (logged as `Updating runner-N server address`). Registration, UUIDs and labels untouched.
+- Verified: fresh start of 5 runners, then all 5 `.runner` files forced to `172.17.0.3:80` and the
+  container recreated on the same volumes: all 5 rewritten to `127.0.0.1:80`, 0 errors, and all 5 listed
+  online in Gitea's `action_runner` table (last_online seconds ago).
+
 ## Fixed — app.ini migrated for Gitea 28.0.0 (template + startup)
 
 - Audited against the Gitea source and the 28.0.0 binary's own startup log. Findings: `[security]
diff --git a/rootfs/usr/local/bin/start-runners b/rootfs/usr/local/bin/start-runners
index 636fa10..f770769 100755
--- a/rootfs/usr/local/bin/start-runners
+++ b/rootfs/usr/local/bin/start-runners
@@ -151,6 +151,12 @@ __register_runner() {
 			return 1
 		fi
 	fi
+	# .runner stores the server address from registration; a container IP baked in earlier goes stale
+	# after a restart, so point it at the current SERVER_ADDRESS every start
+	if [ -f "$runner_dir/.runner" ] && ! grep -q -F -- "\"address\": \"$SERVER_ADDRESS\"" "$runner_dir/.runner"; then
+		__log "Updating $runner_name server address to $SERVER_ADDRESS"
+		sed -i "s|\"address\": *\"[^\"]*\"|\"address\": \"$SERVER_ADDRESS\"|" "$runner_dir/.runner"
+	fi
 	__log "Runner $runner_name registered"
 }
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