# SCOPE

> This file helps you quickly understand what this repository is about,
> when it is relevant, and when it is not.
> It is intentionally lightweight and may be incomplete.

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## One-liner

Headless PDF ingest that turns document bytes into engine-owned evidence
contracts (fingerprint, canonical text, page/offset maps).

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## Core Idea

The rest of the citation-evidence ecosystem (anchoring, evidence linking,
binders) needs a stable, runtime-agnostic way to go from *raw document bytes*
to a `Document` + `DocumentRepresentation`. This repo owns that transformation
for PDFs — pure over bytes, no persistence, no viewer, no UI framework.

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## In Scope

- PDF byte ingest → `{ document, representation }` (`ingestPdf`)
- PDF text extraction → canonical text + page map + gap-free offset map (`extractPdf`)
- SHA-256 byte fingerprinting (`fingerprintBytes`)
- Browser upload helpers behind a separate entry point (`createPdfByteStore`, `ingestPdfFromFile`)

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## Out of Scope

- HTML / Markdown representations (deferred — see `workplans/`)
- Persisting documents or representations (caller's job)
- Viewer URL resolution and blob-vs-fixture policy (stays in `citation-evidence`)
- Citation recovery / external source discovery (deferred)
- Defining domain contracts — those are owned by `citation-engine`

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## Relevant When

- You have PDF bytes and need engine-shaped evidence contracts
- You need a deterministic content fingerprint of document bytes
- You are wiring a new consumer to ingest without pulling in a viewer

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## Not Relevant When

- You need HTML/Markdown ingest (not yet implemented)
- You need viewer/session/UI behavior (see `citation-evidence`)
- You are changing the `Document`/`DocumentRepresentation` contract (see `citation-engine`)

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## Current State

- Status: active
- Implementation: partial (PDF slice implemented; HTML/MD and recovery deferred)
- Stability: evolving
- Usage: internal (consumed by `citation-evidence` across the repo boundary)

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## How It Fits

- Upstream dependencies: `citation-engine` (`@citation-evidence/engine/shared`)
- Downstream consumers: `citation-evidence` (umbrella app)
- Often used with: `citation-engine`, `citation-evidence`

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## Terminology

- Preferred terms: ingest, canonical text, fingerprint, representation
- Also known as: "source" (its former location was `citation-evidence/src/source/`)
- Potentially confusing terms: "representation" (a derived view of a document, not the document itself)

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## Related / Overlapping Repositories

- `citation-engine` — owns the shared `Document`/`DocumentRepresentation` contracts this repo produces
- `citation-evidence` — umbrella app that consumes this ingest core; still owns viewer-url resolution

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## Getting Oriented

- Start with: `README.md`, then `docs/ADR-0001-extraction-boundary.md`
- Key files / directories: `src/pdf/` (headless core), `src/browser/` (upload helpers)
- Entry points: `src/index.ts` (headless), `src/browser/index.ts` (browser)

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## Provided Capabilities

- `capability.infotech.pdf-evidence-ingest` — headless PDF → evidence contracts
  (see `registry/capabilities/`)

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## Notes

Fixture corpus is owned upstream by `citation-evidence` and resolved from a
sibling checkout (ADR-0002); it is not duplicated here.