diff --git a/Makefile b/Makefile
index 866e23f8b9..3a5b8534f8 100644
--- a/Makefile
+++ b/Makefile
@@ -213,7 +213,10 @@ build/icon.png: docs/img/logo.webp scripts/generate-icons.ts
 	@bun scripts/generate-icons.ts png
 
 ## Quality checks (can run in parallel)
-static-check: lint typecheck fmt-check check-eager-imports ## Run all static checks (includes startup performance checks)
+static-check: lint typecheck fmt-check check-eager-imports check-bench-agent ## Run all static checks (includes startup performance checks)
+
+check-bench-agent: ## Verify terminal-bench agent configuration and imports
+	@./scripts/check-bench-agent.sh
 
 lint: node_modules/.installed ## Run ESLint (typecheck runs in separate target)
 	@./scripts/lint.sh
diff --git a/benchmarks/terminal_bench/mux-run.sh b/benchmarks/terminal_bench/mux-run.sh
index 89e0ba4b06..52cc14ab48 100644
--- a/benchmarks/terminal_bench/mux-run.sh
+++ b/benchmarks/terminal_bench/mux-run.sh
@@ -77,7 +77,7 @@ ensure_git_repo "${project_path}"
 log "starting mux agent session for ${project_path}"
 cd "${MUX_APP_ROOT}"
 
-cmd=(bun src/debug/agentSessionCli.ts
+cmd=(bun src/cli/debug/agentSessionCli.ts
   --config-root "${MUX_CONFIG_ROOT}"
   --project-path "${project_path}"
   --workspace-path "${project_path}"
diff --git a/docs/benchmarking.md b/docs/benchmarking.md
index 4afbf2f064..d35ac0f67e 100644
--- a/docs/benchmarking.md
+++ b/docs/benchmarking.md
@@ -65,7 +65,7 @@ The adapter lives in `benchmarks/terminal_bench/mux_agent.py`. For each task it:
 
 1. Copies the mux repository (package manifests + `src/`) into `/tmp/mux-app` inside the container.
 2. Ensures Bun exists, then runs `bun install --frozen-lockfile`.
-3. Launches `src/debug/agentSessionCli.ts` to prepare workspace metadata and stream the instruction, storing state under `MUX_CONFIG_ROOT` (default `/root/.mux`).
+3. Launches `src/cli/debug/agentSessionCli.ts` to prepare workspace metadata and stream the instruction, storing state under `MUX_CONFIG_ROOT` (default `/root/.mux`).
 
 `MUX_MODEL` accepts either the mux colon form (`anthropic:claude-sonnet-4-5`) or the Terminal-Bench slash form (`anthropic/claude-sonnet-4-5`); the adapter normalises whichever you provide.
 
diff --git a/scripts/check-bench-agent.sh b/scripts/check-bench-agent.sh
new file mode 100755
index 0000000000..09b693ad06
--- /dev/null
+++ b/scripts/check-bench-agent.sh
@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# This script verifies that the terminal-bench agent entry point
+# referenced in mux-run.sh is valid and can be executed (imports resolve).
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+MUX_RUN_SH="$REPO_ROOT/benchmarks/terminal_bench/mux-run.sh"
+
+echo "Checking terminal-bench agent configuration..."
+
+if [[ ! -f "$MUX_RUN_SH" ]]; then
+  echo "❌ Error: $MUX_RUN_SH not found"
+  exit 1
+fi
+
+# Extract the agent CLI path from mux-run.sh
+# Looks for line like: cmd=(bun src/cli/debug/agentSessionCli.ts
+CLI_PATH_MATCH=$(grep -o "bun src/.*\.ts" "$MUX_RUN_SH" | head -1 | cut -d' ' -f2)
+
+if [[ -z "$CLI_PATH_MATCH" ]]; then
+  echo "❌ Error: Could not find agent CLI path in $MUX_RUN_SH"
+  exit 1
+fi
+
+FULL_CLI_PATH="$REPO_ROOT/$CLI_PATH_MATCH"
+
+echo "Found agent CLI path: $CLI_PATH_MATCH"
+
+if [[ ! -f "$FULL_CLI_PATH" ]]; then
+  echo "❌ Error: Referenced file $FULL_CLI_PATH does not exist"
+  exit 1
+fi
+
+echo "Verifying agent CLI startup (checking imports)..."
+
+# Run with --help or no args to check if it boots without crashing on imports
+# We expect it to fail with "Unknown option" or "workspace-path required" but NOT with "Module not found" or "worker error"
+if ! output=$(bun "$FULL_CLI_PATH" --help 2>&1); then
+  # It failed, which is expected (no args/bad args), but we need to check WHY
+  exit_code=$?
+
+  # Check for known import/worker errors
+  if echo "$output" | grep -qE "Module not found|Worker error|Cannot find module"; then
+    echo "❌ Error: Agent CLI failed to start due to import/worker errors:"
+    echo "$output"
+    exit 1
+  fi
+
+  # If it failed just because of arguments, that's fine - it means the code loaded.
+  echo "✅ Agent CLI loaded successfully (ignoring argument errors)"
+else
+  echo "✅ Agent CLI ran successfully"
+fi
+
+echo "Terminal-bench agent check passed."
diff --git a/src/node/utils/main/workerPool.ts b/src/node/utils/main/workerPool.ts
index df2ee321ce..40968276c6 100644
--- a/src/node/utils/main/workerPool.ts
+++ b/src/node/utils/main/workerPool.ts
@@ -1,5 +1,5 @@
 import { Worker } from "node:worker_threads";
-import { join, dirname, sep } from "node:path";
+import { join, dirname, sep, extname } from "node:path";
 
 interface WorkerRequest {
   messageId: number;
@@ -37,7 +37,17 @@ const hasDist = pathParts.includes("dist");
 const srcIndex = pathParts.lastIndexOf("src");
 
 let workerDir: string;
-if (srcIndex !== -1 && !hasDist) {
+let workerFile = "tokenizer.worker.js";
+
+// Check if we're running under Bun (not Node with ts-jest)
+// ts-jest transpiles .ts files but runs them via Node, which can't load .ts workers
+const isBun = !!(process as unknown as { isBun?: boolean }).isBun;
+
+if (isBun && extname(__filename) === ".ts") {
+  // Running from source via Bun - use .ts worker directly
+  workerDir = currentDir;
+  workerFile = "tokenizer.worker.ts";
+} else if (srcIndex !== -1 && !hasDist) {
   // Replace 'src' with 'dist' in the path (only if not already in dist)
   pathParts[srcIndex] = "dist";
   workerDir = pathParts.join(sep);
@@ -45,7 +55,7 @@ if (srcIndex !== -1 && !hasDist) {
   workerDir = currentDir;
 }
 
-const workerPath = join(workerDir, "tokenizer.worker.js");
+const workerPath = join(workerDir, workerFile);
 const worker = new Worker(workerPath);
 
 // Handle messages from worker