Coding-Easy-Truncate-String

The model receives the prompt (and optional system message). The run uses scorer javascript_function_tests with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Return JSON only with a string field named code. The code must be dependency-free JavaScript, define the requested function in the top level or module.exports, and include no markdown, imports, require, timers, network, filesystem, eval, or placeholders.

Implement function truncateString(str, maxLen). If the string length exceeds maxLen, truncate it so that the total length including the appended '...' equals maxLen (i.e. keep the first maxLen-3 characters then append '...'). If the string is at most maxLen characters long, return it unchanged.

Your JSON must look like {"code":"function truncateString(...) { ... }"}.

{
  "function_name": "truncateString",
  "timeout_ms": 100,
  "test_pass_threshold": 1,
  "partial_credit_threshold": 0.5,
  "tests": "[hidden executable tests]"
}