# Capture capability — use-case & BDD specification

**Status:** Decisions resolved 2026-06-22 (§4). Ready for implementation scoping. `capture` is a
privileged cross-harness write path touching brain + Gitea + ai-sessions.
**Tracks:** hyperguild #49.
**Governed by:** `infra/docs/architecture/01-invariants.md` (I1–I5), the admissibility test in
`00-synthesis-model.md`, and the distributed-consolidation shape mandated by
`brain/wiki/homelab/decisions/no-centralized-cross-harness-observer-2026-06-17.md`.

---

## 1. Use-case (Clean Architecture form)

**Name:** CaptureSession
**Actor:** A harness acting on the user's behalf (claude.ai Chat/Cowork/Code/Design, Claude Code
CLI, Crush, Pi, LLM Council, Agentsquad executor/reviewer) — or the user directly.
**Goal:** Durably persist a finished session's valuable output — insights → brain, action items →
Gitea tickets, optional summary → ai-sessions — with one uniform invocation, identical core
behaviour across harnesses.

**Primary success scenario (essential steps):**
1. Caller assembles capture input (insights, tickets, optional summary) + context (harness,
   session_ref, fidelity, actor, **data-classification**).
2. System validates the whole request (fail-closed).
3. System resolves **effective classification** (stricter of caller-declared and target-derived)
   and the **server-derived harness origin** (from the authenticated principal). It checks the
   **sovereignty gate** (I1): if effective classification is confidential AND the origin is a
   non-sovereign (us-nexus) surface, the capture is **refused** before any write.
4. System persists insights (write or supersede), tickets (create/close/comment), summary — each
   best-effort, recording per-item outcome.
5. System emits an **audit record** (I5) of who/what captured what, when, via which principal.
6. System returns a structured, partial-aware receipt.

**Architectural shape:** the *logic* is a shared use-case (`CaptureService`), invoked **per-harness
against the caller's own credentials** (distributed consolidation — no high-degree observer node).
A central authenticated relay endpoint exists ONLY as a fallback for harnesses that cannot run the
use-case in-process (Crush/Pi/headless); the relay holds no standing visibility and retains nothing
beyond the I5 audit log.

---

## 2. Invariant obligations (acceptance gates, not nice-to-haves)

| Invariant | Obligation on `capture` |
|---|---|
| **I1 sovereign containment** | A confidential-classified session MUST NOT be captured through a us-nexus harness. Harness origin is **server-derived from the authenticated principal** (not caller-asserted). Classification uses **model (C)**: caller declares, server cross-checks the target's tag, **stricter wins**, mismatch logged. See §4.1–4.2. |
| **I2 deliberate acceptance** | The *distributed-library* form opens no new acceptance. IF a central relay node is deployed, its cross-harness reach MUST be entered in `infra/docs/security-baseline.md` with Why-accepted / Revisit-if before it ships. |
| **I3 GitOps reconcilability** | IF `capture` runs as a deployed service, its manifest lives under `infra/k3s/apps/**` (sovereign source, Flux-reconciled). No untracked runtime. |
| **I4 decisions captured** | The distributed-vs-central decision and the intent-named-verb pattern are recorded (ADR + brain). |
| **I5 auditability** | Every capture emits a request-level audit record to the alloy/loki substrate: actor/principal, harness, items written, timestamp. |

---

## 3. BDD scenarios (Gherkin)

```gherkin
Feature: Capture session value uniformly across harnesses
  As an operator working across many AI harnesses
  I want one uniform command to persist insights and file tickets
  So that valuable session output is never lost and is always auditable

  Background:
    Given a brain store, a Gitea issue tracker, and an ai-sessions summary writer
    And the caller is authenticated with a principal
    And the session context declares a harness, a fidelity, and a data classification

  # --- Core happy path ---
  Scenario: Capture insights and tickets from a non-confidential session
    Given a session classified as "internal"
    And the capture input has 2 insights and 1 ticket to create
    When capture is invoked
    Then both insights are written to the brain and their ids and content hashes are returned
    And the ticket is created in the named repo under owner "mathias"
    And an audit record is emitted naming the principal, harness, and items written
    And the receipt reports every item as ok

  # --- I1: sovereignty gate (the load-bearing refusal) ---
  # Harness origin is server-derived from the authenticated principal, never from context.harness.
  Scenario: Refuse capture of a confidential session through a us-nexus harness
    Given a session whose effective classification is "confidential"
    And the authenticated principal resolves to a us-nexus harness origin
    When capture is invoked
    Then the capture is refused before any write
    And no insight, ticket, or summary is persisted
    And the refusal names the sovereignty invariant as the reason

  Scenario: Allow capture of a confidential session through a sovereign harness
    Given a session whose effective classification is "confidential"
    And the authenticated principal resolves to a sovereign-soil harness origin
    When capture is invoked
    Then the capture proceeds and persists normally

  Scenario: Ignore a caller-asserted harness label and use the server-derived origin
    Given the request context asserts harness "sovereign-soil"
    But the authenticated principal resolves to a us-nexus origin
    And the session classification is "confidential"
    When capture is invoked
    Then the capture is refused
    And the server-derived origin is used, not the asserted label
    And the asserted-vs-derived discrepancy is logged as a security event

  # --- I1: classification model (C) — stricter of declared vs target-derived wins ---
  Scenario: Take the stricter classification when caller and target disagree
    Given the caller declares classification "internal"
    But the target wing/repo is tagged "confidential"
    When capture is invoked
    Then the effective classification is "confidential"
    And the declared-vs-derived mismatch is logged as a security event
    And the I1 gate is evaluated against "confidential"

  Scenario: Honour a caller raising sensitivity above the target's tag
    Given the caller declares classification "confidential"
    And the target wing/repo is tagged "internal"
    When capture is invoked
    Then the effective classification is "confidential"
    And the capture is gated as confidential

  # --- Supersession + staleness discipline (reuses #45 / #47 resolution) ---
  Scenario: Supersede a prior insight rather than duplicating it
    Given an insight whose context names an existing note to supersede
    When capture is invoked
    Then the existing note is updated in place, not duplicated
    And the prior content hash is recorded in the superseding note
    And read-after-write confirmation uses a direct fetch, never a semantic query

  # --- Validation: fail-closed ---
  Scenario: Reject a malformed request before any write
    Given a capture input with an invalid wing/hall or unknown repo
    When capture is invoked
    Then the request is rejected with a validation error
    And nothing is written to the brain, Gitea, or ai-sessions

  # --- Partial failure: best-effort + honest receipt ---
  Scenario: Report partial success when one item fails mid-capture
    Given a capture input with 2 insights and 1 ticket
    And the second insight write will fail
    When capture is invoked
    Then the first insight and the ticket are persisted
    And the second insight is reported as failed in the receipt
    And no rollback is attempted
    And the audit record reflects exactly what landed

  # --- Dry run ---
  Scenario: Preview a capture without writing
    Given a valid capture input with dry_run true
    When capture is invoked
    Then the would-be receipt is returned
    And nothing is written anywhere

  # --- I5: auditability is non-optional, but degrades rather than blocks ---
  Scenario: Capture proceeds under a durable local audit buffer when the central sink is down
    Given the central audit substrate (loki) cannot be written to
    When capture is invoked
    Then the capture proceeds
    And the audit record is written to a durable LOCAL fallback buffer
    And an ntfy alert is emitted naming the degraded audit state
    And the receipt flags that audit was buffered locally, not centrally recorded
    # Never UN-audited: the write is buffered durably and reconciled on recovery.

  Scenario: Locally buffered audit records reconcile to the central sink on recovery
    Given audit records were buffered locally during a sink outage
    When the central audit substrate becomes reachable again
    Then the buffered records are replayed to the central sink
    And the local buffer is cleared only after confirmed central write

  Scenario: Capture refuses if even the local audit buffer cannot be written
    Given neither the central sink nor the local fallback buffer can be written
    When capture is invoked
    Then the capture is refused
    And the reason names the auditability invariant
    # Degrade-and-warn has a floor: if NOTHING can record the audit, do not write.

  # --- Summary fidelity (collision rule from the retro work) ---
  Scenario: A richer-fidelity summary supersedes a thinner one for the same session
    Given a summary already exists for session_ref X at fidelity "live-capture"
    And a new summary arrives for session_ref X at fidelity "transcript-parse"
    When capture is invoked
    Then the transcript-parse summary supersedes the live-capture one
    And the live-capture summary is not left as a contradicting duplicate
```

---

## 4. Resolved decisions (2026-06-22)

These were open questions at draft; resolved in the 2026-06-22 review session. Recorded here as
binding design decisions for the build.

1. **Classification trust — model (C): caller-declares + server-cross-checks, stricter wins.**
   The caller declares `context.classification`; the server **independently derives** the target's
   classification (from the target wing/repo's classification tag) and gates on the **stricter of
   the two**. The caller can voluntarily *raise* sensitivity but can never *lower* it below the
   target's floor. A declared-vs-derived **mismatch is logged as a security event** (I5).
   - **Prerequisite (new build work):** a classification taxonomy (e.g. `public` /
     `internal` / `confidential`) and a per-wing / per-repo classification tag the server can read.
     This must exist before the I1 gate is load-bearing. Tracked as a sub-task of #49.
   - Rationale: composes with decision 2; fails safe; honours a caller flagging something *more*
     sensitive than its destination. Pure caller-trust (A) was rejected — it makes the gate theatre.

2. **Sovereign-harness determination — server-derived, not caller-asserted.**
   "Is this harness us-nexus / sovereign?" is derived from the **authenticated principal/origin**
   (the OAuth2 identity), never from `context.harness`. `context.harness` survives only as a
   self-reported label for the audit log — descriptive telemetry, **never a gate input**. A control
   keyed on an attacker-suppliable value is not a control.

3. **Central relay — ships in v1, with the I2 ledger entry.**
   The relay is required, not optional: claude.ai (Chat/Cowork/Design), Crush, Pi, and LLM Council
   cannot run the use-case library in-process, and those are primary day-to-day surfaces. Deferring
   the relay would ship a capability that doesn't work from the interfaces actually in use. Because
   the relay is a (thin, no-standing-visibility, audit-only-retention) central node, its cross-harness
   reach **must be entered in `infra/docs/security-baseline.md`** with Why-accepted / Revisit-if
   **before it ships** (I2). That ledger entry is v1 work, not a follow-up.

4. **Audit-sink-down — degrade-and-warn, with a durable local buffer + reconcile-on-recovery.**
   If the central audit sink (loki) is unreachable, capture **proceeds** rather than blocking
   (availability), BUT the audit record is written to a **durable local fallback buffer** and an
   **ntfy alert** fires. Buffered records **reconcile to the central sink on recovery**; the local
   buffer clears only after confirmed central write. **Floor:** if *neither* the central sink nor the
   local buffer can be written, capture **refuses** — degrade-and-warn never means *un*-audited.
   - Rationale: keeps capture available during an observability outage while preserving I5 — the
     write is always recorded *somewhere durable*, just not centrally until reconciliation. This is
     the difference between an I5 violation and an I5-compliant degraded mode, and it must be
     presentable as such to a due-diligence client.