Bound Copilot safeoutputs -32602 empty-args retry loops with SDK session circuit-breaker

[Copilot]

Reviewer workflows were spending the full step timeout when the Copilot turn repeatedly called write-once safeoutputs tools with empty arguments (-32602: Empty arguments are not allowed) and never converged. This change adds a bounded failure path so those turns terminate quickly instead of burning 15 minutes.

• SDK guardrail: repeated empty-argument safeoutputs rejection

  • In actions/setup/js/copilot_sdk_session.cjs, added detection for consecutive -32602 empty-argument rejections on the same safeoutputs tool.
  • Introduced a circuit-breaker threshold (2 consecutive failures per tool) and early session disconnect when exceeded.
  • Emits a structured guard event:
    • guard.safeoutputs_empty_args_rejections_exceeded
  • Upgrades terminal guidance in the error path to explicitly stop empty-arg retries and prefer tools/list (single schema inspection) or noop.

• Failure classification remains scoped

  • Guard only applies to mcpServerName === "safeoutputs" and only on failed tool completions matching the empty-args rejection pattern.
  • Non-matching failures and single occurrences continue through existing retry/error paths.

• Targeted coverage for the new behavior

  • In actions/setup/js/copilot_sdk_driver.test.cjs, added tests for:
    • fast-fail after repeated empty-arg -32602 rejections for the same safeoutputs tool;
    • no guard trigger on a single rejection.

const isSafeOutputsEmptyArgsRejection =
  mcpServerName === "safeoutputs" &&
  !success &&
  SAFEOUTPUTS_EMPTY_ARGS_REJECTION_PATTERN.test(resultText);

if (isSafeOutputsEmptyArgsRejection) {
  const streak = (safeOutputsEmptyArgsStreakByTool.get(toolKey) ?? 0) + 1;
  if (streak >= SAFEOUTPUTS_EMPTY_ARGS_MAX_CONSECUTIVE) {
    catastrophicSafeOutputsEmptyArgsError = new Error(
      `safeoutputs empty-arguments rejection loop detected ...`
    );
    void session.disconnect();
  }
}