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+visibility: public
+---
+
+# ADR-0004: Linq as the primary channel
+
+**Status:** Accepted
+**Date:** 2026-04-23
+**Deciders:** Jacob
+
+## Context
+
+picortex could target several messaging protocols:
+
+- **Linq** — iMessage + SMS partner API; the same one Cortex uses.
+- **Slack** — noos already has a Slack bot; well-trodden path.
+- **Telegram** — OpenClaw uses it; good bot API.
+- **Native iMessage via BlueBubbles / AppleScript** — sketchy, not scalable.
+- **OpenChat** — Jacob's own messaging app; would need a linq-compatible adapter (candidate for D3).
+
+Jacob's explicit goal: "chat with Claude Code from my phone, via iMessage, including group texts."
+
+Only Linq offers a legitimate iMessage + iMessage-groups surface without running macOS + JavaScript-for-Automation chicanery.
+
+## Decision
+
+**Linq is the primary channel. linq-sim (Cortex `cloudcli/dev-tools/linq-sim`) is the dev/testing channel. OpenChat with a linq-compatible adapter is a deferred secondary channel (D3).**
+
+Interface abstraction in picortex is shaped to Linq's event vocabulary (14 event types). Anything talking to picortex over its inbound webhook must conform — this way linq-sim, real Linq, and a future OpenChat adapter are interchangeable.
+
+## Consequences
+
+### Positive
+
+- Dev loop is Cortex-quality from day 1: linq-sim provides iMessage-shaped traffic without real phone numbers.
+- Reuses Cortex's HMAC webhook contract exactly (same `{timestamp}.{raw_body}` signing).
+- No phone-tree / no carrier setup until Jacob is ready for real Linq.
+- Future OpenChat work pays dividends because adapter can also serve picortex.
+
+### Negative
+
+- Linq is a paid partner API; real deployment costs money.
+- Locks event model to Linq's shape. If we later want Slack-first, we'd need an adapter.
+- Linq's group-text behavior is specific — no cross-channel semantics.
+
+### Mitigations
+
+- Interface: picortex defines a `Channel` interface; `LinqChannel` is the v1 implementation. Adapters for Slack/Telegram/OpenChat can plug in without touching core logic.
+- No hard Linq-specific calls in business logic. All outbound goes via the Channel abstraction.
+- linq-sim parity check: automated tests emit every event type linq-sim supports.
+
+## Related
+- [Spec: Linq integration](../specs/006-linq-integration.md)
+- [Wiki: Linq protocol](../wiki/linq-protocol.md)
+- [Wiki: OpenChat adapter](../wiki/openchat-adapter.md)
+- [Cortex inheritance — linq webhook shape](../wiki/cortex-inheritance.md#linq-webhook-shape)
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