diff --git a/packages/loopover-engine/src/miner/cli-subprocess-driver.ts b/packages/loopover-engine/src/miner/cli-subprocess-driver.ts
index b8c66ee659..6b6fcc77ad 100644
--- a/packages/loopover-engine/src/miner/cli-subprocess-driver.ts
+++ b/packages/loopover-engine/src/miner/cli-subprocess-driver.ts
@@ -92,15 +92,22 @@ const CODING_AGENT_ENV_ALLOWLIST = [
  *  - `--output-format json` produces a single parseable JSON result on stdout, matching `claudeErrorStatus`'s
  *    own `JSON.parse(stdout.trim())` assumption (which was already written for this shape, just never
  *    actually triggered because this flag was never passed).
- *  - `--permission-mode acceptEdits` is the same edit-permission scope the Agent-SDK driver already uses
- *    (#4267) -- file edits run unattended inside the scoped worktree, nothing broader.
+ *  - `--permission-mode acceptEdits` alone (the CLI's own edit-permission scope, matching the label the
+ *    Agent-SDK driver's `permissionMode` also uses, #4267) only auto-approves file EDIT tool calls -- it
+ *    does NOT grant `Read` or `Bash`, so a real task (which needs both to explore the repo and run tests)
+ *    got every one of those calls denied in a headless `--print` invocation with no TTY to resolve an
+ *    interactive prompt, silently producing zero real work every time (#6840). `--allowedTools Read Bash`
+ *    grants exactly the two additional tool classes the task actually needs, confirmed via a live
+ *    end-to-end reproduction (zero denials, a real fix + test committed) -- deliberately narrower than
+ *    `--permission-mode bypassPermissions`, which also disables edit-scope confirmation and any other
+ *    safety rail the CLI has, not just the Read/Bash gap this task actually hits.
  *  There is no turn-budget flag on the real CLI (verified via `claude --help`) and no acceptance-criteria
  *  flag either -- the coding agent discovers `task.acceptanceCriteriaPath` itself via its own Read tool
  *  inside the scoped working directory, exactly like the Agent-SDK driver already does (agent-sdk-driver.ts
  *  never passes it as a distinct option either; only `task.instructions` is forwarded as the prompt there
  *  too). The wall-clock `timeoutMs` (already implemented) is this provider's only real turn/cost ceiling. */
 export function defaultClaudeCliArgs(task: CodingAgentDriverTask): string[] {
-  return ["--print", "--output-format", "json", "--permission-mode", "acceptEdits", task.instructions];
+  return ["--print", "--output-format", "json", "--permission-mode", "acceptEdits", "--allowedTools", "Read", "Bash", "--", task.instructions];
 }
 
 /** Real, verified `codex exec` non-interactive argv (confirmed against `codex exec --help`, #5135
diff --git a/test/unit/cli-subprocess-driver.test.ts b/test/unit/cli-subprocess-driver.test.ts
index 5c8f77b0cc..126b529a01 100644
--- a/test/unit/cli-subprocess-driver.test.ts
+++ b/test/unit/cli-subprocess-driver.test.ts
@@ -41,10 +41,24 @@ describe("createCliSubprocessCodingAgentDriver (#4266)", () => {
       "json",
       "--permission-mode",
       "acceptEdits",
+      "--allowedTools",
+      "Read",
+      "Bash",
+      "--",
       "Fix the pagination bug.",
     ]);
   });
 
+  it("#6840: grants Read and Bash in addition to acceptEdits -- acceptEdits alone denies every Read/Bash tool call, silently blocking all real work", async () => {
+    const { spawn, calls } = fakeSpawn({ stdout: "done", code: 0 });
+    const driver = createCliSubprocessCodingAgentDriver({ command: "claude", spawn });
+    await driver.run(TASK);
+    const args = calls[0]?.args ?? [];
+    const allowedToolsIndex = args.indexOf("--allowedTools");
+    expect(allowedToolsIndex).toBeGreaterThan(-1);
+    expect(args.slice(allowedToolsIndex + 1, allowedToolsIndex + 3)).toEqual(["Read", "Bash"]);
+  });
+
   it("uses codex's own real default argv (the exec subcommand, not claude's flags)", async () => {
     const { spawn, calls } = fakeSpawn({ stdout: "done", code: 0 });
     const driver = createCliSubprocessCodingAgentDriver({ command: "codex", spawn });