[corlin]

Stacked on #22 (which now targets main and includes #21). Merge #22 first.

What

The comparison itself (ADR 0011). One chart = one patent's claims × one confirmed product feature set.

• A person confirms claim features and records per-feature findings.
• Claim-level conclusions are derived on read with the exact all-elements algorithm (ADR 0008).
• As decided, findings are manual only: no automated suggestions.
• Backend only; the screen is the next PR.

Design points

• Snapshot at creation: creating a chart freezes the latest fetched claim document as parsed at that moment (claim numbers, dependencies, feature texts and spans, parser ID, claims-text SHA-256, what the text represents, warnings). Recorded findings therefore can't drift onto different features after a re-fetch or a parser change.
• Guards: the product set must be confirmed and from the same case. Claims not yet fetched return 409; no external calls are made in the request path.
• Input rules, enforced in both the service and DB CHECK constraints:
  • literally_present / present_by_equivalent must cite product feature codes from the chart's own product set
  • present_by_equivalent / absent need a rationale
  • equivalence is a professional judgment that is supplied, never computed
• Caveats on every response:
  • US text is as granted (reexamination, IPR and corrections aren't reflected)
  • EP text may be a translation
  • conclusions are not a legal opinion

Storage (tenant data, FORCE RLS)

Table	Mutability
fto_charts	append-only
fto_chart_claim_features	text frozen. Roles may update only the confirmation columns, and a trigger forbids revoking a confirmation
fto_feature_findings	append-only: history kept, latest wins

API — /cases/{case}/fto/charts

Create · list · get (with conclusions and the features found absent) · confirm a claim's features · record a finding · finding history.

Audit summaries contain IDs, claim numbers and finding values only: no claim text, product text or rationale.

Tests

2 Postgres integration tests through the real app:

• the guards
• undetermined → reads_literally after confirmation → does_not_read once a feature is absent, inherited by the dependent claim
• input rules, history, caveats (US and EP)
• wrong case and other tenant both get 404
• audit privacy (checked with a marker string)
• DB immutability (snapshot text, confirmation revocation, findings, charts)

Mutation check: treating unconfirmed features as confirmed fails the flow test.

Validation

• ./scripts/test-postgres.sh: 121 passed (+2)
• .venv/bin/pytest apps/api/tests/unit/: 423 passed
• pnpm test:web: 66 passed; pnpm build:web: ok
• verify-source-lock, verify-scaffold, verify-p0-02, verify-p0-e2e, docker compose config: ok

🤖 Generated with Claude Code