---
id: capability.infotech.pdf-evidence-ingest
name: Headless PDF Evidence Ingest
summary: Turns raw PDF bytes into an engine-shaped Document + DocumentRepresentation — SHA-256 fingerprint, canonical text, page map, and gap-free offset map — as a runtime-agnostic library with no viewer, persistence, or React coupling.
owner: evidence-source
status: draft
domain: infotech
tags:
  - pdf
  - ingest
  - fingerprint
  - canonical-text
  - evidence

maturity:
  discovery:
    current: D2
    target: D5
    confidence: medium
    rationale: >
      Intent, scope, and boundary are documented (ADR-0001/0002) and the
      surface is exercised by a fixture-driven contract suite plus a
      cross-repo consumer round-trip. HTML/MD ingest and citation recovery
      are declared out of scope for now, so discovery is bounded to the PDF
      slice.
  availability:
    current: A1
    target: A3
    confidence: medium
    rationale: >
      Consumable today as a linked library (`link:../evidence-source`) via the
      package root (`@citation-evidence/evidence-source`) and browser subpath.
      Reaching A3 needs a published/versioned artifact rather than a
      sibling-checkout link.

external_evidence:
  completeness:
    level: C1
    confidence: medium
    basis: scope_vs_intent_and_consumer_expectations
    satisfied_expectations:
      - PDF bytes -> Document + DocumentRepresentation
      - deterministic SHA-256 fingerprint
      - canonical text with gap-free page offset map
    broken_expectations: []
    out_of_scope_expectations:
      - HTML / Markdown ingest
      - metadata enrichment beyond pass-through options
      - citation recovery / external source discovery
  reliability:
    level: R1
    confidence: medium
    basis: consumer_quality_signals
    known_reliability_risks:
      - PDF.js worker must be configured by the host before extraction
      - text-extraction fidelity varies on scanned/OCR-noisy PDFs

discovery:
  intent: >
    Let any consumer turn a PDF into engine-owned evidence contracts without
    inheriting a viewer, a store, or a UI framework.
  includes:
    - PDF byte ingest (ingestPdf)
    - PDF text extraction to canonical text + page/offset maps (extractPdf)
    - SHA-256 byte fingerprint (fingerprintBytes)
    - browser upload helpers behind a separate entry point (createPdfByteStore, ingestPdfFromFile)
  excludes:
    - HTML / Markdown ingest
    - persistence of documents/representations
    - viewer URL resolution (stays in the consuming app)
    - citation recovery
  assumptions:
    - domain contracts come from '@citation-evidence/engine/shared'
    - host configures the PDF.js worker before extraction
  use_cases:
    - citation-evidence umbrella consumes ingest across the repo boundary
  research_memos: []

availability:
  current_level: A1
  target_level: A3
  current_artifacts:
    - '@citation-evidence/evidence-source (package root, headless core)'
    - '@citation-evidence/evidence-source/browser (upload helpers)'
  target_artifacts:
    - published versioned package
  consumption_modes:
    - library import

relations:
  depends_on: []
  supports: []
  related_to: []

evidence:
  documentation:
    - README.md
    - docs/ADR-0001-extraction-boundary.md
    - docs/ADR-0002-fixture-ownership.md
  tests:
    - src/pdf/ingest.test.ts
    - src/pdf/fingerprint.test.ts
    - src/browser/byte-store.test.ts
    - src/browser/upload.test.ts
  consumer_feedback: []
  bug_reports: []
  incidents: []

consumer_guidance:
  recommended_for:
    - headless PDF -> evidence-contract ingest in Node or the browser
    - deterministic content fingerprinting of document bytes
  not_recommended_for:
    - non-PDF formats (not yet implemented)
    - high-fidelity extraction from scanned/OCR-only PDFs
  known_limitations:
    - PDF only for now
    - requires host-configured PDF.js worker
    - fixtures resolved from sibling citation-evidence checkout (ADR-0002)

promotion_history:
  - date: "2026-07-08"
    dimension: discovery
    from: D0
    to: D2
    rationale: PDF ingest slice extracted, documented (ADR-0001/0002), and covered by contract tests plus a cross-repo consumer round-trip (ESRC-WP-0001).
    author: claude-code
---

# Headless PDF Evidence Ingest

## Overview

`evidence-source` turns raw PDF bytes into the two engine-owned contracts that
the rest of the citation-evidence ecosystem builds on — a `Document` (media
type, SHA-256 fingerprint, optional title/uri/metadata) and a
`DocumentRepresentation` (`pdf-text`: canonical text, page map, and a gap-free
offset map). Ingest is pure over bytes: no persistence, no viewer state, no
React.

The YAML front matter above is the machine-readable source of truth for
maturity, evidence, relations, and consumer guidance.

## Assessment notes

### Discovery

The boundary is fixed in ADR-0001 (which files are headless core vs. browser
helpers vs. app-only viewer concerns) and ADR-0002 (fixture ownership). The
public surface is small and stable: `ingestPdf`, `extractPdf`,
`fingerprintBytes`, plus browser upload helpers behind a separate entry point.

### Availability

Consumed today as a linked library via `link:../evidence-source`. The umbrella
app (`citation-evidence`) imports the headless core and browser helpers through
a thin façade and runs its source ↔ anchor round-trip across the boundary.
Target A3 requires a published, versioned artifact.

### Completeness

PDF only. HTML/Markdown representations, metadata enrichment, and citation
recovery are explicitly deferred to follow-on workplans (see README) and are
recorded as out-of-scope expectations rather than gaps.

### Reliability

Backed by a fixture-driven contract suite (fingerprint determinism, page/offset
invariants, known-good quote presence) and a downstream consumer round-trip.
The main reliability caveat is extraction fidelity on scanned/OCR-noisy PDFs,
which is inherent to text-layer extraction.

## Promotion checklist

- [x] ID follows `capability.<domain>.<name>` pattern
- [x] Maturity enums match `specs/CapabilityMaturityStandard.md`
- [x] `external_evidence` is populated separately from `maturity`
- [x] Relations reference valid capability IDs
- [x] Index entry added or updated in `registry/indexes/capabilities.yaml`