Config: apply config.env before substitution (#1813)

Co-authored-by: SPANISH FLU <spanishflu-est1918@users.noreply.github.com>

CHANGELOG.md

@@ -21,6 +21,7 @@ Status: unreleased.
 - Routing: precompile session key regexes. (#1697) Thanks @Ray0907.
 - TUI: avoid width overflow when rendering selection lists. (#1686) Thanks @mossein.
 - Telegram: keep topic IDs in restart sentinel notifications. (#1807) Thanks @hsrvc.
+- Config: apply config.env before ${VAR} substitution. (#1813) Thanks @spanishflu-est1918.
 
 ## 2026.1.24-3
 

src/config/io.ts

@@ -211,6 +211,11 @@ export function createConfigIO(overrides: ConfigIoDeps = {}) {
         parseJson: (raw) => deps.json5.parse(raw),
       });
 
+      // Apply config.env to process.env BEFORE substitution so ${VAR} can reference config-defined vars
+      if (resolved && typeof resolved === "object" && "env" in resolved) {
+        applyConfigEnv(resolved as ClawdbotConfig, deps.env);
+      }
+
       // Substitute ${VAR} env var references
       const substituted = resolveConfigEnvVars(resolved, deps.env);
 
@@ -365,6 +370,11 @@ export function createConfigIO(overrides: ConfigIoDeps = {}) {
         };
       }
 
+      // Apply config.env to process.env BEFORE substitution so ${VAR} can reference config-defined vars
+      if (resolved && typeof resolved === "object" && "env" in resolved) {
+        applyConfigEnv(resolved as ClawdbotConfig, deps.env);
+      }
+
       // Substitute ${VAR} env var references
       let substituted: unknown;
       try {