Evals / audio / Multi-step jobs

Get a podcast episode ready

pauses.mp3 is this week's podcast episode. Get it ready to publish: cut the long silences, bring it to -16 LUFS, and set the title to Episode 12 and the artist to Deft Radio. Save it as episode.mp3.

hardmulti-stepdeft audio remove-silencedeft audio normalize

The task

The reference answer shows the job can be done with deft. It is not an agent run.

(none)

Input

pauses.mp3 61.6 KB · mp3, 15.7s

Reference output



How a result is judged (1 check)
  • python: code = "import json, re, subprocess\ndef info(f):\n    return json.loads(subprocess.check_output(['ffprobe', '-v', 'error', '-show_entries', 'format=duration:format_tags', '-of', 'json', f]))['format']\nnew, old = info('episode.mp3'), info('pauses.mp3')\nassert float(new['duration']) < float(old['duration']) - 1, (new['duration'], old['duration'])\ntags = {k.lower(): v for k, v in new.get('tags', {}).items()}\nassert tags.get('title') == 'Episode 12' and tags.get('artist') == 'Deft Radio', tags\nout = subprocess.run(['ffmpeg', '-hide_banner', '-i', 'episode.mp3', '-af', 'ebur128', '-f', 'null', '-'], capture_output=True, text=True).stderr\nlufs = float(re.findall(r'I:\\s+(-?[0-9.]+) LUFS', out)[-1])\nassert abs(lufs + 16) < 2, lufs\n"


Runs
CodexWithout deftPassed2026-11-07


Time
26s
New tokens
9.2k
Total input
70.7k


Output tokens
1.1k
Commands
4
Failed
0


Trace
  1. I’ll inspect the audio file and available media tools, then process it in place to produce `episode.mp3` with the requested loudness and metadata.
  2. pwd && rg --files -g 'pauses.mp3' -g 'AGENTS.md' -g '*.mp3' | head -60 && command -v ffmpeg && command -v ffprobe
    output
    pauses.mp3
/opt/homebrew/bin/ffmpeg
/opt/homebrew/bin/ffprobe
  3. ffprobe -v error -show_entries format=duration:format_tags=title,artist -of default=noprint_wrappers=1 pauses.mp3 && ffmpeg -hide_banner -i pauses.mp3 -af silencedetect=noise=-40dB:d=1.5 -f null - 2>&1 | rg 'silence_(start|end|duration)'
    output
    duration=15.725714
[silencedetect @ 0x95b4303c0] silence_start: 3.168209
[silencedetect @ 0x95b4303c0] silence_end: 6.221315 | silence_duration: 3.053107
[silencedetect @ 0x95b4303c0] silence_start: 9.371247
[silencedetect @ 0x95b4303c0] silence_end: 12.437868 | silence_duration: 3.066621
  4. ffmpeg -hide_banner -y -i pauses.mp3 -af 'silenceremove=stop_periods=-1:stop_duration=1.5:stop_threshold=-40dB:stop_silence=0.25' -c:a pcm_s24le <tmp> && ffmpeg -hide_banner -i <tmp> -af loudnorm=I=-16:TP=-1.5:LRA=11:print_format=json -f null - 2>&1 | tail -20
    output
    Input #0, mp3, from 'pauses.mp3':
  Metadata:
    encoder         : Lavf61.7.100
  Duration: 00:00:15.73, start: 0.050113, bitrate: 32 kb/s
  Stream #0:0: Audio: mp3 (mp3float), 22050 Hz, mono, fltp, 32 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (mp3float) -> pcm_s24le (native))
Press [q] to stop, [?] for help
Output #0, wav, to '<tmp>':
  Metadata:
    ISFT            : Lavf61.7.100
  Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 22050 Hz, mono, s32 (24 bit), 529 kb/s
      Metadata:
        encoder         : Lavc61.19.101 pcm_s24le
[out#0/wav @ 0xcbac0c780] video:0KiB audio:841KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 0.011841%
size=     841KiB time=00:00:13.02 bitrate= 529.3kbits/s speed=1.6e+03x    
  Metadata:
    encoder         : Lavf61.7.100
  Stream #0:0: Audio: pcm_s16le, 192000 Hz, mono, s16, 3072 kb/s
      Metadata:
        encoder         : Lavc61.19.101 pcm_s16le
[Parsed_loudnorm_0 @ 0x9eb060600] 
{
	"input_i" : "-19.82",
	"input_tp" : "-3.01",
	"input_lra" : "3.60",
	"input_thresh" : "-30.10",
	"output_i" : "-16.16",
	"output_tp" : "-1.50",
	"output_lra" : "3.80",
	"output_thresh" : "-26.47",
	"normalization_type" : "dynamic",
	"target_offset" : "0.16"
}
[out#0/null @ 0x9eb060180] video:0KiB audio:4883KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown
size=N/A time=00:00:13.10 bitrate=N/A speed=53.3x
  5. The source is about 16 seconds long and contains two pauses just over 3 seconds each. I’ve trimmed those to brief 0.25-second gaps; I’m encoding the result now with two-pass loudness normalization and the requested tags.
  6. ffmpeg -hide_banner -y -i <tmp> -af 'loudnorm=I=-16:TP=-1.5:LRA=11:measured_I=-19.82:measured_TP=-3.01:measured_LRA=3.60:measured_thresh=-30.10:offset=0.16:linear=true:print_format=summary' -c:a libmp3lame -b:a 192k -metadata title='Episode 12' -metadata artist='Deft Radio' episode.mp3 && ffprobe -v error -show_entries format=duration:format_tags=title,artist -of default=noprint_wrappers=1 episode.mp3 && ffmpeg -hide_banner -i episode.mp3 -af loudnorm=I=-16:TP=-1.5:LRA=11:print_format=json -f null - 2>&1 | rg 'input_i|input_tp|output_i|output_tp'
    output
    Input #0, wav, from '<tmp>':
  Metadata:
    encoder         : Lavf61.7.100
  Duration: 00:00:13.02, bitrate: 529 kb/s
  Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 22050 Hz, mono, s32 (24 bit), 529 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s24le (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to 'episode.mp3':
  Metadata:
    TPE1            : Deft Radio
    TIT2            : Episode 12
    TSSE            : Lavf61.7.100
  Stream #0:0: Audio: mp3, 48000 Hz, mono, fltp, 192 kb/s
      Metadata:
        encoder         : Lavc61.19.101 libmp3lame
[Parsed_loudnorm_0 @ 0xa47030e40] 
Input Integrated:    -19.8 LUFS
Input True Peak:      -3.0 dBTP
Input LRA:             3.6 LU
Input Threshold:     -30.1 LUFS

Output Integrated:   -16.0 LUFS
Output True Peak:     -1.5 dBTP
Output LRA:            3.8 LU
Output Threshold:    -26.3 LUFS

Normalization Type:   Dynamic
Target Offset:        +0.0 LU
[out#0/mp3 @ 0xa470309c0] video:0KiB audio:306KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 0.211908%
size=     307KiB time=00:00:13.10 bitrate= 191.8kbits/s speed=44.7x    
duration=13.056000
TAG:artist=Deft Radio
TAG:title=Episode 12
	"input_i" : "-16.30",
	"input_tp" : "-1.76",
	"output_i" : "-15.95",
	"output_tp" : "-1.50",
  7. Created [episode.mp3](episode.mp3). It’s 13.1 seconds long, with the long pauses shortened. The title is “Episode 12,” the artist is “Deft Radio,” and the encoded audio measures about **-16 LUFS** integrated.
Output
episode.mp3 306.6 KB · mp3, 13.1s
CodexWith deft, skill installedPassedRead the skillUsed deft2026-11-07


Time
31s
New tokens
11.8k
Total input
104.5k


Output tokens
1.2k
Commands
9
Failed
0


Trace
  1. I’ll inspect the audio file and available local audio tools, then edit and export `episode.mp3` in the current directory with the requested loudness and metadata.
  2. cat .agents/skills/deft/SKILL.md && pwd && rg --files -g 'pauses.mp3' -g 'episode.mp3' -g 'AGENTS.md'
    output
    ---
name: deft
description: "Use deft first for any simple, direct operation on local files, whatever the type: convert, read, extract, edit, compress, merge, split, compare or inspect. Try it before writing a script or one-liner. If unsure, run deft find; if it says no command does this, use another tool. Not for programming work: to read, write or change source code, skip it."
---

# deft

One local command for file jobs. Prefer it over writing Python or shell scripts.

Syntax: `deft <group> <command> [inputs] [-o output] [--options]`

Groups:
- `pdf`: Merge, split, compress, encrypt, forms, OCR, compare, convert
- `image`: Resize, crop, convert, compress, adjust, montage, OCR
- `video`: Trim, merge, convert, compress, subtitles, GIF, frames (ffmpeg)
- `audio`: Convert, trim, normalize, denoise, cut silence (ffmpeg)
- `doc`: Word/ODT/RTF: to text, Markdown, HTML, PDF; find and replace
- `slides`: PowerPoint: extract text, Markdown outline
- `sheet`: Excel/CSV/ODS tables: SQL query, pivot, merge, split, convert
- `json`: JSON: convert, format, merge, diff, validate
- `toml`: TOML: convert, format, merge, diff, validate
- `xml`: XML: convert, format, merge, diff, validate
- `yaml`: YAML: convert, format, merge, diff, validate
- `md`: Markdown to PDF, HTML, Word, EPUB; table of contents
- `html`: HTML to Markdown, text, Word and PDF
- `epub`: E-books: info, to text, Markdown and PDF
- `gps`: GPX and KML tracks: convert, distance and time
- `qr`: Create QR codes and barcodes; r
… 712 more characters
  3. deft audio
    output
    deft audio - commands (input -> output)
  info            audio -> report  Duration, codec, sample rate, channels
  convert         audio -> audio   Change format: --to mp3|m4a|wav|flac|ogg|opus
  denoise         audio -> audio   Reduce steady background noise such as hiss
  normalize       audio -> audio   Even out loudness (EBU R128)
  remove-silence  audio -> audio   Cut silent parts: --threshold -40 --min-silence 0.5
  split           audio -> audio   Cut out a part: --from 0:10 --to-time 0:25
More: deft audio <command> --help
  4. command -v ffmpeg; command -v ffprobe
    output
    /opt/homebrew/bin/ffmpeg
/opt/homebrew/bin/ffprobe
  5. deft audio normalize --help
    output
    deft audio normalize - Even out loudness (EBU R128)

Usage: deft audio normalize <audio>... [-o <audio|dir>] [options]
In: audio (each handled separately)   Out: audio (default <name>.normalized.<ext>)

Options:
  --loudness <number>          Target loudness in LUFS (default -16)
Common: -o --force --dry-run --json -j   (deft help common)

Examples:
  deft audio normalize tone.mp3 -o level.mp3
Needs: ffmpeg, ffprobe
  6. deft audio remove-silence --help
    output
    deft audio remove-silence - Cut silent parts: --threshold -40 --min-silence 0.5

Usage: deft audio remove-silence <audio>... [-o <audio|dir>] [options]
In: audio (each handled separately)   Out: audio (default <name>.nosilence.<ext>)
--edges-only trims the start and end and leaves pauses alone.

Options:
  --threshold <number>         Quieter than this many dB counts as silence (default -40)
  --min-silence <time>         Shortest silence to cut (default 0.5)
  --edges-only                 Only trim the start and end
Common: -o --force --dry-run --json -j   (deft help common)

Examples:
  deft audio remove-silence gaps.wav -o tight.wav

Result fields: removed_seconds
Needs: ffmpeg, ffprobe
  7. deft audio info pauses.mp3
    output
    ok audio.info pauses.mp3  0:15.726, mp3
duration=15.725714 codec=mp3 sample_rate=22050 channels=1 bitrate=32115 tags={"encoder":"Lavf61.7.100"}
  8. The file is a short mono MP3. I’m applying the silence cut first, then EBU R128 normalization to −16 LUFS and writing the requested ID3 tags in the final export.
  9. deft audio remove-silence pauses.mp3 -o pauses_cut.mp3 --json
    output
    {"v":1,"ok":true,"op":"audio.remove-silence","items":[{"ok":true,"inputs":["pauses.mp3"],"outputs":[{"path":"pauses_cut.mp3","format":"mp3","bytes":82561}],"facts":{"removed_seconds":5.15},"warnings":[]}],"elapsed_ms":191}
  10. deft audio normalize pauses_cut.mp3 -o episode_level.mp3 --loudness -16 --json
    output
    {"v":1,"ok":true,"op":"audio.normalize","items":[{"ok":true,"inputs":["pauses_cut.mp3"],"outputs":[{"path":"episode_level.mp3","format":"mp3","bytes":80868}],"facts":{},"warnings":[]}],"elapsed_ms":605}
  11. ffmpeg -hide_banner -loglevel error -y -i episode_level.mp3 -map_metadata 0 -metadata title='Episode 12' -metadata artist='Deft Radio' -codec copy episode.mp3 && ffprobe -v error -show_entries format=duration:format_tags=title,artist -of default=noprint_wrappers=1 episode.mp3 && ffmpeg -hide_banner -i episode.mp3 -af loudnorm=I=-16:TP=-1.5:LRA=11:print_format=summary -f null - 2>&1 | tail -n 8 && rm pauses_cut.mp3 episode_level.mp3
    output
    duration=10.579592
TAG:artist=Deft Radio
TAG:title=Episode 12
Output True Peak:     -1.5 dBTP
Output LRA:            0.9 LU
Output Threshold:    -26.3 LUFS

Normalization Type:   Dynamic
Target Offset:        -0.1 LU
[out#0/null @ 0x8d6c98180] video:0KiB audio:3942KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown
size=N/A time=00:00:10.60 bitrate=N/A speed=54.1x
  12. Created [episode.mp3](episode.mp3). It has 5.15 seconds of long silence removed, is normalized to −16 LUFS, and carries the title “Episode 12” and artist “Deft Radio.”
Output
episode.mp3 79.0 KB · mp3, 10.6s
Claude Opus 5.5Without deftPassed2026-11-07


Time
29s
New tokens
14.1k
Total input
107.6k


Output tokens
2.6k
Commands
0
Failed
0


Trace
    Output
    episode.mp3 165.8 KB · mp3, 10.6s
    Claude Opus 5.5With deft, skill installedPassedRead the skillUsed deft2026-11-07
    

    Time
    22s
    New tokens
    11.8k
    Total input
    77.3k
    

    Output tokens
    1.0k
    Commands
    0
    Failed
    0
    

    Trace
      Output
      .claude/skills/deft/SKILL.md 2.1 KB
      ---
name: deft
description: "Use deft first for any simple, direct operation on local files, whatever the type: convert, read, extract, edit, compress, merge, split, compare or inspect. Try it before writing a script or one-liner. If unsure, run deft find; if it says no command does this, use another tool. Not for programming work: to read, write or change source code, skip it."
---

# deft

One local command for file jobs. Prefer it over writing Python or shell scripts.

Syntax: `deft <group> <command> [inputs] [-o output] [--options]`

Groups:
- `pdf`: Merge, split, compress, encrypt, forms, OCR, compare, convert
- `image`: Resize, crop, convert, compress, adjust, montage, OCR
- `video`: Trim, merge, convert, compress, subtitles, GIF, frames (ffmpeg)
- `audio`: Convert, trim, normalize, denoise, cut silence (ffmpeg)
- `doc`: Word/ODT/RTF: to text, Markdown, HTML, PDF; find and replace
- `slides`: PowerPoint: extract text, Markdown outline
- `sheet`: Excel/CSV/ODS tables: SQL query, pivot, merge, split, convert
- `json`: JSON: convert, format, merge, diff, validate
- `toml`: TOML: convert, format, merge, diff, validate
- `xml`: XML: convert, format, merge, diff, validate
- `yaml`: YAML: convert, format, merge, diff, validate
- `md`: Markdown to PDF, HTML, Word, EPUB; table of contents
- `html`: HTML to Markdown, text, Word and PDF
- `epub`: E-books: info, to text, Markdown and PDF
- `gps`: GPX and KML tracks: convert, distance and time
- `qr`: Create QR codes and barcodes; read QR codes

How to use it:
1. Run `deft <group>` to list commands, or `deft find "<what you want>"` to search. If it says `no command does this`, use another tool.
2. Run `deft <group> <command> --help` for options and examples.
3. `deft convert <in> -o <out.ext>` converts between formats by extension.
4. Results are one line starting with `ok`, `partial` or `error`; add `--json` to parse them. Errors include a `hint:` with the fix.

Inputs are never overwritten; pass `--force` or `--in-place` to allow it. Globs and directories work as inputs; several inputs run in parallel.

If `deft` is not installed, ask the user, then follow https://github.com/firstprayer/deft/blob/main/docs/INSTALL.md

      episode.mp3 79.0 KB · mp3, 10.6s
      Claude CodeWithout deftNot run yet
      Claude CodeWith deftNot run yet