Evals / config / Compare and merge

Layer two configs

Merge prod.yaml over config.yaml and save the result as final.yaml.

normalsingledeft yaml merge

The task

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

deft yaml merge config.yaml prod.yaml -o final.yaml

Input

config.yaml 125 B
service:
  name: billing
  port: 8080
  debug: true
database:
  host: localhost
  pool: 5
features:
  - invoices
  - refunds
prod.yaml 65 B
service:
  port: 80
  debug: false
database:
  host: db.internal

Reference output

final.yaml 122 B
service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
- invoices
- refunds
How a result is judged (1 check)
  • python: code = "import yaml; d = yaml.safe_load(open('final.yaml')); assert d['service'] == {'name': 'billing', 'port': 80, 'debug': False}, d"

Runs

CodexWithout deftPassed2026-11-07

Time
12s
New tokens
3.7k
Total input
53.7k
Output tokens
0.3k
Commands
3
Failed
0

Trace

  1. I’ll inspect the two YAML files and merge `prod.yaml` over `config.yaml`, with production values taking precedence, then save the merged document as `final.yaml`.

  2. pwd && rg --files -g 'config.yaml' -g 'prod.yaml' -g 'AGENTS.md'
    output
    prod.yaml
config.yaml
  3. cat config.yaml && cat prod.yaml
    output
    service:
  name: billing
  port: 8080
  debug: true
database:
  host: localhost
  pool: 5
features:
  - invoices
  - refunds
service:
  port: 80
  debug: false
database:
  host: db.internal
  4. cat > final.yaml <<'EOF' service: name: billing port: 80 debug: false database: host: db.internal pool: 5 features: - invoices - refunds EOF cat final.yaml
    output
    service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
  - invoices
  - refunds

  5. Merged `prod.yaml` over `config.yaml` and saved the result as [final.yaml](final.yaml). Production values take precedence; other config values were retained.

Output

final.yaml 126 B
service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
  - invoices
  - refunds

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

Time
14s
New tokens
4.9k
Total input
71.0k
Output tokens
0.4k
Commands
5
Failed
0

Trace

  1. I’ll inspect the two YAML files and use `deft` for the merge, then save `final.yaml` in the current directory.

  2. cat ../../../../../../../...agents/skills/deft/SKILL.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
… 700 more characters
  3. deft yaml
    output
    deft yaml - commands (input -> output)
  convert   yaml -> data       Change format: --to json|toml|xml|jsonl
  diff      yaml... -> report  Compare two files by structure
  format    yaml -> yaml       Tidy a file: --sort-keys
  merge     yaml... -> yaml    Deep-merge files; later files win
  validate  yaml -> report     Check syntax, or a JSON Schema with --schema
More: deft yaml <command> --help
  4. pwd && rg --files -g 'config.yaml' -g 'prod.yaml' -g 'final.yaml'
    output
    prod.yaml
config.yaml
  5. deft yaml merge --help
    output
    deft yaml merge - Deep-merge files; later files win

Usage: deft yaml merge <yaml>... [-o <yaml|dir>] [options]
In: yaml (all together, in order)   Out: yaml (default <name>.merged.<ext>)

Options:
  --arrays <replace|append>    What to do with two lists at one key (default replace)
Common: -o --force --dry-run --json -j   (deft help common)

Examples:
  deft yaml merge config.yaml override.yaml -o merged.yaml
  6. deft yaml merge config.yaml prod.yaml -o final.yaml
    output
    ok yaml.merge config.yaml prod.yaml -> final.yaml  122B  0.00s

  7. Merged `prod.yaml` over `config.yaml` and saved the result as [final.yaml](final.yaml).

Output

final.yaml 122 B
service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
- invoices
- refunds

Claude Opus 5.5Without deftPassed2026-11-07

Time
11s
New tokens
9.4k
Total input
42.4k
Output tokens
0.8k
Commands
0
Failed
0

Trace

    Output

    final.yaml 122 B
    service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
- invoices
- refunds

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

    Time
    9s
    New tokens
    9.8k
    Total input
    59.1k
    Output tokens
    0.5k
    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
      final.yaml 122 B
      service:
  name: billing
  port: 80
  debug: false
database:
  host: db.internal
  pool: 5
features:
- invoices
- refunds

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