diff --git a/hive-ag3nt/src/mcp.rs b/hive-ag3nt/src/mcp.rs
index 2df48a2..bced8cc 100644
--- a/hive-ag3nt/src/mcp.rs
+++ b/hive-ag3nt/src/mcp.rs
@@ -1383,13 +1383,20 @@ pub fn render_claude_config(agent_binary: &str, socket: &std::path::Path) -> Str
             "env": {}
         }),
     );
-    for (name, spec) in load_extra_mcp() {
+    // Auto-inject HYPERHIVE_STATE_DIR so extra MCP servers can resolve the
+    // agent's durable state dir without the agent author hard-coding it.
+    // User-supplied env takes precedence — we only fill in the missing key.
+    let state_dir = crate::paths::state_dir();
+    for (name, mut spec) in load_extra_mcp() {
         if name == SERVER_NAME {
             tracing::warn!(
                 "extra MCP server name `{SERVER_NAME}` collides with the built-in surface; ignoring",
             );
             continue;
         }
+        spec.env
+            .entry("HYPERHIVE_STATE_DIR".to_owned())
+            .or_insert_with(|| state_dir.display().to_string());
         servers.insert(
             name,
             serde_json::json!({
diff --git a/hive-c0re/src/meta.rs b/hive-c0re/src/meta.rs
index 6774e66..c2d67fa 100644
--- a/hive-c0re/src/meta.rs
+++ b/hive-c0re/src/meta.rs
@@ -273,11 +273,22 @@ fn render_flake(
                 name = name;
                 email = "${name}@hyperhive";
               };
+              # Container-wide env: every service + co-process daemon can
+              # resolve the agent's durable state dir without hard-coding it.
+              environment.variables = {
+                HIVE_LABEL = name;
+                HYPERHIVE_STATE_DIR =
+                  if isManager then "/state"
+                  else "/agents/${name}/state";
+              };
               systemd.services.${service}.environment = {
                 HIVE_PORT = toString port;
                 HIVE_LABEL = name;
                 HIVE_DASHBOARD_PORT = toString dashboardPort;
                 HIVE_OPERATOR_PRONOUNS = operatorPronouns;
+                HYPERHIVE_STATE_DIR =
+                  if isManager then "/state"
+                  else "/agents/${name}/state";
               };
             }
           ];