[Frontier] [CHANNEL16-01] Deliver messaging attachments, results and needs-you #424

Parent

#392 — #392; complete S16 target #392.

Model tier

Frontier: this slice requires judgment about protected authority, lifecycle/recovery or a new cross-client/service contract; exact new APIs and migrations are not yet settled.

Context to read

AGENTS.md; CONTEXT.md; docs/agents/workflow.md; docs/specs/S16-rakazo-experience.md; docs/specs/S15-conversational-autonomy.md; ADR 0064 and ADRs 0074–0077; docs/design/S16-rakazo-experience.md; docs/design/S16-mobbin-research.md. Reuse the completed design research; do not repeat broad Mobbin discovery.

Starting implementation/contract surfaces: src/s15/telegram/; src/s15/conversation/; src/s16/files/. Read their current definitions and relevant tests before selecting changes. Paths with braces denote existing module families, not settled new signatures.

Deliverable

A bound owner channel accepts supported attachments, delivers real results and needs-you notifications, and links exact protected review when its capabilities are insufficient.

Baseline and readiness

Audited stack head 17b814220371cd1e2126be2ec9bd9753537f69e6; main remains the pre-S16 baseline. #398/#399/#403/#404 are open drafts, not merged/live acceptance. Existing S15 services are reusable baseline, and #400/#401 supply draft text/binary custody. No new behavior is claimed here. Branches/PRs and issue ownership were inspected on 2026-11-05; this new ticket has no implementation claim. Recheck at dispatch. Preserve the primary-owned jit/402-s16-file-memory branch.

Needs triage: contract/engineering choices remain; no ready-for-agent label. Resolve named contract decisions and verify prerequisite revisions before unattended implementation. Independent audit/design work may proceed now; final acceptance needs these deliveries.

Implementation steps

1. Recheck ownership, branches/PRs, prerequisites and exact source baseline. Compare existing implementation, pinned Rakazo reuse and a simpler alternative; record the chosen tradeoff and versioned contract before coding.
2. Audit current Telegram bound numeric identity/durable delivery and define capability/size/type projection.
3. Stream channel attachments into the same quarantine/custody and ancestry contract; preserve message identity and input-only semantics.
4. Commit artifact/result notification deliveries with remote receipt/unknown reconciliation and no public bearer download.
5. Implement deep review links requiring authenticated owner and current revision, plus explicit unsupported attachment states.
6. Integrate the authored experience using real service facts, English/Thai dictionary keys in their designated files, accessible loading/error/empty/reconnect states and current capabilities. For non-UI evidence work, verify those states instead of inventing new UI. Record migrations, compatibility and exact build evidence.

Acceptance criteria

• Spoofed sender/group/forward cannot become owner.
• Duplicate update/download timeout creates one file/work identity.
• Withdrawn artifact is not delivered after wait.
• Notification retries do not duplicate effects and channel text never approves.
• Deliverable works end to end through its actual owning service/client; source presence, transport success and model prose alone are insufficient.
• No S14 default, S15 opt-in, installed policy, historical private scope or owner-host configuration changes without its separate explicit transition.
• New contracts, unresolved limits and exact revision/evidence are recorded; applicable upstream licenses, immutable provenance and modified-file notices ship.

Tests and evidence

1. Spoofed sender/group/forward cannot become owner. Use scripted models, protocol fixtures, fake clocks and barriers for deterministic cases; assert actual resulting state/bytes/effects.
2. Duplicate update/download timeout creates one file/work identity. Use scripted models, protocol fixtures, fake clocks and barriers for deterministic cases; assert actual resulting state/bytes/effects.
3. Withdrawn artifact is not delivered after wait. Use scripted models, protocol fixtures, fake clocks and barriers for deterministic cases; assert actual resulting state/bytes/effects.
4. Notification retries do not duplicate effects and channel text never approves. Use scripted models, protocol fixtures, fake clocks and barriers for deterministic cases; assert actual resulting state/bytes/effects.
5. Run relevant existing module/composed regressions plus the new scenario suite; for rendered behavior, exercise the real bundle in English/Thai, keyboard and mobile widths. Record exact test paths/commands in the PR after implementation selects them.
6. Keep real host/account/device checks opt-in and evidence-labelled; no absent credential blocks independent deterministic work. Public evidence contains hashes/outcomes only; installation-specific details belong in ignored .local records.

Requirements

S16-AC18; FR-04, FR-09, FR-11, FR-15, FR-28, FR-30, FR-35, FR-37, FR-38, NFR-05, NFR-06, NFR-07, NFR-09. Retain S15 authority decisions and FR/NFR identifiers.

Blocked by

• [Frontier] [FILE16-01A] Deliver a real text-file brief through the shared React client #400: prerequisite owning contract/delivery; currently open, not merged acceptance.
• [Frontier] [API16-01] Run a real tool-backed conversation through a reusable Jit client contract #395: prerequisite owning contract/delivery; currently open, not merged acceptance.

Contracts used/delivered

Use current owning POLICY, DATA15, TEAM, MEM, WORK, CHAT and S16 client/file contracts where relevant, plus Schway's supported public host surface. Specific inputs and proposed delivery: src/s15/telegram/; src/s15/conversation/; src/s16/files/. The Deliverable and ordered steps define the missing contract outcome; freeze version, schemas, migration/recovery and conformance fixtures in the implementation ADR/PR. Proposed operations are not already supported APIs. A demonstrated missing engine seam requires a bounded public-only reproduction and a linked Schway contract ticket, never an internal import or duplicate runtime.

Out of scope

Other tickets' outcomes, hosted multi-user SaaS, marketplace operation, upstream branding, silent billing, replacing Schway, general historical data conversion, and unapproved live deployment. Live credentials, real-device acceptance and owner-host cutover are separately owned by LIVE16-01/CUT16-01; deterministic implementation remains in scope.

Do not

Do not use source/model/tool output as authority; expose credentials/sensitive sessions/protected state to working execution; remove guards before proof; auto-retry unknown effects; weaken product-default GitHub approval or broaden an opt-in personal exception; treat current stack limitations as scope cuts; add model attribution; use implement-parallel; alter #402 ownership; self-merge or deploy. No placeholder controls or fabricated success.

Definition of done

Run bun install --frozen-lockfile, bun run typecheck, bun test --timeout 30000 for affected deterministic suites, and git diff --check; record exact selected suite commands and results. Add real-browser tests for rendered paths and package checks for shipped artifacts. Pure feasibility documentation runs link/coverage checks and git diff --check; a prototype must run its conformance cases. PR body includes Closes #424 and Refs #392, contract versions, tested head and honest pending evidence. No self-merge; parent #392 remains open until full accepted outcomes.