fix: add cmux __tmux-compat prefix to interactive_bash tool

Extract isCmuxCompatEnvironment to shared module and fix
interactive_bash to resolve cmux executables with the __tmux-compat
prefix, matching all other tmux command paths in the codebase.

src/shared/tmux/cmux-detect.ts

@@ -0,0 +1,11 @@
+/**
+ * Detect whether we are running inside cmux (cmux omo).
+ * When cmux-omo sets up the environment it injects a tmux shim and sets
+ * CMUX_SOCKET_PATH / TMUX. If detected, redirect tmux commands to
+ * `cmux __tmux-compat` so they become native cmux splits instead of
+ * failing because there is no real tmux server running.
+ */
+export function isCmuxCompatEnvironment(): boolean {
+	return Boolean(process.env.CMUX_SOCKET_PATH) ||
+		process.env.TMUX?.includes("cmuxterm") === true
+}

src/shared/tmux/index.ts

@@ -1,4 +1,5 @@
 export * from "./types"
 export * from "./constants"
+export * from "./cmux-detect"
 export * from "./runner"
 export * from "./tmux-utils"

src/shared/tmux/runner.ts

@@ -1,4 +1,5 @@
 import { spawn } from "../bun-spawn-shim"
+import { isCmuxCompatEnvironment } from "./cmux-detect"
 
 type RunTmuxOptions = {
 	retry?: number
@@ -29,18 +30,6 @@ function isTerminalTmuxError(stderr: string): boolean {
 	return TERMINAL_TMUX_ERROR_PATTERN.test(stderr)
 }
 
-/**
- * Detect whether we are running inside cmux (cmux omo).
- * When cmux-omo sets up the environment it injects a tmux shim and sets
- * CMUX_SOCKET_PATH / TMUX. If detected, redirect tmux commands to
- * `cmux __tmux-compat` so they become native cmux splits instead of
- * failing because there is no real tmux server running.
- */
-function isCmuxCompatEnvironment(): boolean {
-	return Boolean(process.env.CMUX_SOCKET_PATH) ||
-		process.env.TMUX?.includes("cmuxterm") === true
-}
-
 function resolveTmuxExecutable(tmuxPath: string): string[] {
 	if (!isCmuxCompatEnvironment()) {
 		return [tmuxPath]

src/tools/interactive-bash/tmux-path-resolver.ts

@@ -1,14 +1,10 @@
 import { spawn } from "../../shared/bun-spawn-shim"
+import { isCmuxCompatEnvironment } from "../../shared/tmux/cmux-detect"
 
 let tmuxPath: string | null = null
 let initPromise: Promise<string | null> | null = null
 let tmuxPathEnvironmentKey: "cmux" | "tmux" | null = null
 
-function isCmuxCompatEnvironment(): boolean {
-  return Boolean(process.env.CMUX_SOCKET_PATH) ||
-    process.env.TMUX?.includes("cmuxterm") === true
-}
-
 function getEnvironmentKey(): "cmux" | "tmux" {
   return isCmuxCompatEnvironment() ? "cmux" : "tmux"
 }

src/tools/interactive-bash/tools.ts

@@ -1,8 +1,19 @@
 import { tool, type ToolDefinition } from "@opencode-ai/plugin/tool"
 import { spawnWithWindowsHide } from "../../shared/spawn-with-windows-hide"
+import { isCmuxCompatEnvironment } from "../../shared/tmux/cmux-detect"
 import { BLOCKED_TMUX_SUBCOMMANDS, DEFAULT_TIMEOUT_MS, INTERACTIVE_BASH_DESCRIPTION } from "./constants"
 import { getCachedTmuxPath } from "./tmux-path-resolver"
 
+function resolveTmuxExecutable(tmuxPath: string): string[] {
+  if (!isCmuxCompatEnvironment()) {
+    return [tmuxPath]
+  }
+
+  const executableName = tmuxPath.split(/[\\/]/).pop()
+  const cmuxExecutable = executableName === "cmux" ? tmuxPath : "cmux"
+  return [cmuxExecutable, "__tmux-compat"]
+}
+
 /**
  * Quote-aware command tokenizer with escape handling
  * Handles single/double quotes and backslash escapes without external dependencies
@@ -90,7 +101,7 @@ tmux capture-pane -p -t ${sessionName} -S -1000
 The Bash tool can execute these commands directly. Do NOT retry with interactive_bash.`
       }
 
-      const proc = spawnWithWindowsHide([tmuxPath, ...parts], {
+      const proc = spawnWithWindowsHide([...resolveTmuxExecutable(tmuxPath), ...parts], {
         stdout: "pipe",
         stderr: "pipe",
       })