The closed-task test of 2026-10-24 (AO-065), exactly as the six subagents got it.
Each ran as a Claude Code subagent (general-purpose type) with model opus or sonnet and effort low, medium or high, in its own copy of this folder.

===== PROMPT (folder path shortened to <folder>) =====
Closed task. Follow these steps exactly and do nothing else.

Folder: <folder>

1. Read SPEC.md and test_duration.py in that folder.
2. Write duration.py in that folder, implementing parse_duration exactly as SPEC.md says.
3. Run the tests with Bash: python -I "<folder>/test_duration.py"
4. If anything fails, fix duration.py and run the tests again, until the output is ALL 39 PASSED.

Do not edit the test file, create any other file, read anything outside that folder, load skills, or start agents. When the tests pass, reply with one line: DONE, then the number of times you ran the tests.

===== SPEC.md =====
# parse_duration

Write `duration.py` with one function, `parse_duration(text: str) -> int`, that returns a
length of time in whole seconds. It accepts exactly four formats and raises `ValueError` for
anything else.

1. **Plain seconds.** One or more digits: `"45"` is 45.
2. **Units.** One or more groups of `<digits><unit>`, units `d` (86400), `h` (3600),
   `m` (60), `s` (1), case-insensitive. Groups may be separated by one space or nothing.
   Each unit appears at most once, and units must appear in the order d, h, m, s.
   `"1h30m"`, `"1h 30m"` and `"2D 5S"` are valid; `"30m1h"`, `"1h1h"` and `"1h  30m"`
   (two spaces) are not.
3. **Clock.** `M:SS` or `H:MM:SS`. `H` and `M` are one or more digits; `MM` and `SS` are
   exactly two digits from 00 to 59. `"1:30"` is 90; `"1:02:03"` is 3723; `"1:60"` and
   `"1:2"` are invalid.
4. **ISO 8601 subset.** `P`, then optionally `<digits>D`, then optionally `T` followed by
   one or more of `<digits>H`, `<digits>M`, `<digits>S` in that order. Upper case only.
   At least one number must appear. `"PT1H30M"` is 5400; `"P1DT2S"` is 86402; `"P"`,
   `"PT"`, `"P1DT"` and `"pt1h"` are invalid.

Leading and trailing whitespace is ignored. An empty or all-space string is invalid.
Signs, decimals and any other character make the input invalid. Zero is a valid answer
(`"0s"` is 0).

===== test_duration.py =====
import sys
sys.path.insert(0, __file__.rsplit("\\", 1)[0].rsplit("/", 1)[0])
from duration import parse_duration

GOOD = [
    ("45", 45), ("0", 0), ("0s", 0), ("90s", 90), ("2d", 172800), ("1h30m", 5400),
    ("1h 30m", 5400), ("2D 5S", 172805), ("1d2h3m4s", 93784), ("  7m  ", 420),
    ("1:30", 90), ("0:05", 5), ("1:02:03", 3723), ("100:00:00", 360000),
    ("PT1H30M", 5400), ("P1DT2S", 86402), ("P2D", 172800), ("PT0S", 0), ("PT90M", 5400),
]
BAD = [
    "", "   ", "-5", "1.5h", "30m1h", "1h1h", "1h  30m", "1x", "h", "1:60", "1:2",
    "1:02:3", ":30", "P", "PT", "P1DT", "pt1h", "PT1M1H", "1h30", "P1H",
]

failed = 0
for text, want in GOOD:
    try:
        got = parse_duration(text)
    except Exception as e:  # noqa: BLE001
        got = f"raised {type(e).__name__}"
    if got != want:
        failed += 1
        print(f"FAIL {text!r}: want {want}, got {got}")
for text in BAD:
    try:
        got = parse_duration(text)
        failed += 1
        print(f"FAIL {text!r}: want ValueError, got {got!r}")
    except ValueError:
        pass
    except Exception as e:  # noqa: BLE001
        failed += 1
        print(f"FAIL {text!r}: want ValueError, got {type(e).__name__}")

total = len(GOOD) + len(BAD)
print(f"ALL {total} PASSED" if not failed else f"{failed} of {total} FAILED")