Evals / audio / Tags and facts

Answer a question about audio

What is the duration of example.ogg in seconds? Write the number to duration.txt.

easysingledeft audio info

The task

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

deft audio info example.ogg > duration.txt

Input

example.ogg 102.3 KB · vorbis, 6.1s

Reference output

duration.txt 152 B
ok audio.info example.ogg  0:06.104, vorbis
duration=6.104036 codec=vorbis sample_rate=44100 channels=2 bitrate=137342 tags={"encoder":"Lavf59.27.100"}
How a result is judged (1 check)
  • text: file = "duration.txt", contains = ["6."]

Runs

CodexWithout deftPassed2026-11-07

Time
12s
New tokens
3.4k
Total input
53.5k
Output tokens
0.3k
Commands
3
Failed
0

Trace

  1. I’ll inspect the audio metadata, then write its duration in seconds to `duration.txt` in the current directory.

  2. pwd && rg --files -g 'example.ogg' -g 'duration.txt'
    output
    example.ogg
  3. ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 example.ogg
    output
    6.104036
  4. printf '6.104036\\n' > duration.txt && cat duration.txt
    output
    6.104036

  5. `example.ogg` is 6.104036 seconds long. I wrote `6.104036` to [duration.txt](duration.txt).

Output

duration.txt 9 B
6.104036

CodexWith deft, skill installedPassedRead the skillUsed deft2026-11-07

Time
18s
New tokens
7.3k
Total input
71.0k
Output tokens
0.5k
Commands
4
Failed
0

Trace

  1. I’ll inspect the audio file’s metadata, then write its duration in seconds to `duration.txt` in the current directory.

  2. cat .agents/skills/deft/SKILL.md && pwd && ls -l example.ogg
    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
… 760 more characters
  3. deft find "audio duration metadata"
    output
    audio info         audio -> report    Duration, codec, sample rate, channels
video from-images  image... -> video  Slideshow: --duration, --fps, --audio
  4. deft audio info example.ogg
    output
    ok audio.info example.ogg  0:06.104, vorbis
duration=6.104036 codec=vorbis sample_rate=44100 channels=2 bitrate=137342 tags={"encoder":"Lavf59.27.100"}
  5. printf '6.104036\\n' > duration.txt && cat duration.txt
    output
    6.104036

  6. `example.ogg` is 6.104036 seconds long. I wrote `6.104036` to [duration.txt](duration.txt).

Output

duration.txt 9 B
6.104036

CodexWith deft, skill as AGENTS.mdPassed2026-11-05

Time
12s
New tokens
9.7k
Total input
61.1k
Output tokens
0.3k
Commands
3
Failed
0

Trace

  1. I’ll inspect the audio file’s duration, then write the number to `duration.txt` in the current directory.

  2. deft audio --help
    output
    deft audio - commands (input -> output)
  info        audio -> report  Duration, codec, sample rate, channels
  compress    audio -> mp3     Re-encode as MP3 at --bitrate (kbps)
  convert     audio -> audio   Change format: --to mp3|m4a|wav|flac|ogg|opus
  from-video  video -> audio   Save the soundtrack: --to mp3|m4a|wav|flac|ogg
  merge       audio... -> mp3  Join audio files in order
  normalize   audio -> audio   Even out loudness (EBU R128)
  split       audio -> audio   Cut out a part: --from 0:10 --to-time 0:25
More: deft audio <command> --help
  3. deft audio info example.ogg
    output
    ok audio.info example.ogg  0:06.104, vorbis
bitrate=137342 channels=2 codec=vorbis duration=6.104036 sample_rate=44100
  4. pwd && printf '6.104036\\n' > duration.txt && cat duration.txt
    output
    6.104036

  5. `example.ogg` is 6.104036 seconds long. I wrote `6.104036` to [duration.txt](duration.txt).

Output

Its files were not kept in this run. The last line of the trace is its own report.

Claude Opus 5.5Without deftPassed2026-11-07

Time
13s
New tokens
8.7k
Total input
56.3k
Output tokens
0.4k
Commands
0
Failed
0

Trace

    Output

    duration.txt 9 B
    6.104036

    Claude Opus 5.5With deft, skill installedPassedRead the skillUsed deft2026-11-07

    Time
    9s
    New tokens
    10.0k
    Total input
    74.9k
    Output tokens
    0.4k
    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
      duration.txt 9 B
      6.104036

      Claude CodeWithout deftNot run yet

      Claude CodeWith deftNot run yet