Source Extract

Source Extract (Stage 2 Acquisition and Extraction)

Acquire approved sources and extract parseable text for one target work.

This skill is the Stage 2 owner for acquisition and extraction. It consolidates the planned format-specific paths into one stage skill.

It should answer:

• which approved sources were acquired?
• which extraction path was used?
• what raw and extracted artifacts were produced?
• what confidence or OCR warnings need to be carried forward?

It does not own:

• semantic cleaning
• structural segmentation
• source ranking decisions

Quick Status

Raw artifact dirs: !find ${LYCEUM_TEXTS_DIR:-output/texts} -path '*/raw' -type d 2>/dev/null | wc -l Extracted artifact dirs: !find ${LYCEUM_TEXTS_DIR:-output/texts} -path '*/extracted' -type d 2>/dev/null | wc -l PDF tool support docs: !ls scripts/fix_ocr_errors.py 2>/dev/null | wc -l

Commands

• /source-extract run [work] [--source greek|english:<id>|all] — Acquire and extract approved sources
• /source-extract probe [work] [--source <id>] — Determine likely extraction path before full extraction
• /source-extract validate [work] — Spot-check raw vs extracted output and extraction metadata
• /source-extract status [work] — Summarize acquired sources, extraction modes, and warnings

Target: $ARGUMENTS

Owned Responsibilities

Owns

• acquisition of approved source files
• extraction into parseable text
• extraction-path recording
• confidence/OCR warning recording
• preservation of both raw and extracted artifacts

Does not own

• semantic cleanup
• source ranking
• segmentation

Supported Extraction Modes

HTML / TEI / plain text

• fetch source
• strip obvious navigation/boilerplate only where needed for extraction
• preserve headings/references where possible

EPUB

• unpack EPUB
• extract XHTML in spine order
• preserve meaningful section structure
• note nav/TOC/notes stripping decisions

PDF with text layer

• extract text directly
• preserve page boundaries as metadata if practical
• detect headers/footers/marginalia risk

OCR / DjVu fallback

• extract OCR text
• measure OCR quality heuristics
• flag suspect spans/pages
• compare with other witnesses when possible

Manual transcription fallback

• only when necessary
• must include provenance note and explicit warning

Workflows

/source-extract probe

Use before extraction when the format path is unclear.

Determine

• source format
• likely extraction mode
• whether OCR is required
• whether extraction is low-risk or likely noisy

/source-extract run

Acquire and extract the approved sources.

For each source

1. preserve the raw artifact under raw/
2. record the extraction path used
3. write parseable output under extracted/
4. note confidence/warnings
5. preserve enough metadata to make later auditing possible

Important rule

Do not discard the raw source after extraction.

/source-extract validate

Spot-check extraction quality.

Verify for samples

• extracted text matches the source
• headers/footers/marginalia are recognized as risk areas
• references/headings were not lost unnecessarily
• OCR suspect spans are explicitly noted

Useful repo helpers

• scripts/fix_ocr_errors.py for OCR-heavy workflows
• read_pdf when source PDFs need targeted inspection

/source-extract status

Summarize:

• acquired sources
• extraction mode used per source
• warnings/confidence notes
• whether Stage 3 can begin or extraction must be retried

Outputs

Canonical outputs

$LYCEUM_TEXTS_DIR/<slug>/
├── raw/
├── extracted/
├── qa/
├── state.json
└── replay/stage-history.json

Expected report content

• source ID
• extraction mode
• acquisition timestamp
• confidence notes
• suspect spans/pages
• structural preservation notes

Verification Contract

This skill follows the Stage 2 contract from docs/text-pipeline-skill-verification-2026-03-13.md.

Verify

• approved sources were acquired
• extraction path used was recorded
• raw and extracted artifacts exist
• extraction quality/confidence was measured
• sampled extracted text matches source content

Minimum evidence

• files under raw/
• files under extracted/
• extraction report with format path used

Pass criteria

• raw and extracted files exist for all approved sources unless blocked
• extraction mode is explicit
• sample spot checks confirm extracted text matches source pages/sections
• suspect OCR spans or headers/footers are flagged where relevant

Failure examples

• extracted files exist without preserved raw sources
• OCR was used but confidence/suspect spans were not recorded
• extraction silently lost important structural markers

Required next steps

After successful extraction:

• /text-cleaning run <work>
• rerun extraction if a better source or cleaner extraction path becomes available

Verification

After completing this stage, run the automated verification script:

bash scripts/verify_stage_2.sh "${SLUG}"

Exit codes: 0=PASS (advance), 1=FAIL (block), 2=WARN (advance with notes). The orchestrator runs this automatically; when executing manually, check the output for [FAIL] or [WARN] lines.

Key Files