075e984fb5
Folds the 2026-06-26 vision-revision pressure-test into the canonical docs. The spec moves from Proposed to Ratified; the decisions it produced land in the docs it said it would amend, with ADRs recording each load-bearing reversal. - README.md: reframe north star (AI-era contact-center engine, not Asterisk successor); persona; revised pillars (add data-ownership, demote WASM, promote spend-control); update 'what it is/isn't'. - ARCHITECTURE.md: replace three-plane framing with fused per-call vertical + composable horizontal platform; remove control<->media hot-path gRPC hop; make the agent tap the central interface; add DX spine + GUI-as-API-client + k8s declarative/operational model. Also: 'too slow to police' -> 'too slow to enforce' (terminology). - PORT_PLAN.md: recharacterize as capability checklist (not template); graduate contact-center capabilities to first-class domain; Rust-native trunk SIP rows; WASM demoted; thin-slice + capability ladder phasing. - ADR-0001: marked Superseded by ADR-0003. - ADR-0002 (new): north star + fused per-call core. - ADR-0003 (new): Rust-native trunk SIP, no SBC shield. - ADR-0004 (new): GPL-3.0-or-later license. - ADR-0005 (new): Valkey as event bus + state store. - ADR-0006 (new): WebRTC-first ingress; SIP endpoint deferred. - vision-revision spec: status -> Ratified 2026-06-26.
94 lines
5.2 KiB
Markdown
94 lines
5.2 KiB
Markdown
# ADR-0002 — North star & fused per-call core
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- **Status:** Accepted
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- **Date:** 2026-06
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- **Origin:** [vision-revision](../superpowers/specs/2026-06-26-vision-revision-design.md) §1–4, 6–7
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- **Amends:** `README.md`, `docs/ARCHITECTURE.md`, `docs/PORT_PLAN.md` (the founding identity framing)
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## Context
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The founding docs anchored rutster to "memory-safe successor to Asterisk." A pressure-test
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of that anchor:
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1. The PBX category is **already consolidated/eaten** — by UCaaS + Teams Phone. Feature-parity
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with a 1.18M-LOC C monolith is a solo-multi-year death-march into a shrinking market.
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2. Asterisk's durable value is its **place in the world** — *the self-hostable engine technical
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builders stand contact centers on* (Vicidial, GOautodial, a thousand integrator builds) —
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*not* its protocols or its channel/bridge/dialplan architecture.
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3. AI is actively disrupting telephony (voice agents), opening a self-hostable + AI-native slot
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that no incumbent fills: LiveKit has no contact-center domain; cloud CCaaS isn't
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self-hostable and bolts AI on; Vapi/Retell put your calls/data on their infra; Vicidial/FreePBX
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are Asterisk-era PHP+C.
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"Spiritual successor to Asterisk" therefore means successor to its **role**, not its **form**.
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## Decision
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### 1. North star
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rutster is **the open-source engine for building the AI-era contact center** — AI-native, not AI
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bolted-on; self-hostable; owning the contact-center domain; memory-safe Rust. It is a
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**framework/engine, not a turnkey product** (Asterisk never tried to *be* Five9; it was the thing
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people built on). The moment it chases CCaaS GUI-parity, it dies. Asterisk's capability map
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(the PORT_PLAN) is a **completeness checklist**, explicitly **not** an architecture template.
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### 2. Persona
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The 2006 Linux-nerd-who-stood-up-Asterisk-for-an-SMB's modern equivalent: the **CLI/IDE/AI-comfortable
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self-hosting technical builder** who runs Claude Code in a terminal, versions everything in git,
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and self-hosts on principle. *Not* the no-code admin clicking a flow-designer canvas. This
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narrowing is deliberate for an engine, and it liberates the authoring layer — the audience codes
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and has an AI pair, so there is no "dumb it down" tax (see §8 of the vision-revision).
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### 3. Architecture — fused per-call vertical + composable horizontal platform
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The core owns the **per-call vertical** end-to-end as one deterministic, auditable trust domain:
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```
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carrier SIP trunk ─► media termination (RTP/SRTP + local real-time reflexes)
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│
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├─► clean audio tap ──► external agent brain (STT/LLM/TTS)
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│
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└─► in-boundary spend / abuse gate
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```
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**Horizontal platform** concerns are services *around* the core, independently scaled: number
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inventory, billing rollup, analytics, multi-region orchestration, the management API, and the
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agent brain itself.
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This **replaces the founding three-plane framing**:
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- The **control↔media gRPC hop on the per-call hot path** is **removed**. Fusion where fusion
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buys determinism + security + simplicity.
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- The **spend gate** and the **agent tap** — which founding docs externalized (a `☁️ Service` and
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the app plane) — are pulled **into** the boundary, because they are **constitutive** of the wedge
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(a runtime can't structurally enforce spend/abuse control or barge-in if the media is elsewhere).
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- It is neither monolith nor pure microservices: **fused where fusion buys the wedge; composable
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where independent scaling matters.**
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### 4. Pillars re-weighted
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| Pillar | Change | Why |
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|---|---|---|
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| Memory-safety | ▲ stronger | Now **literally true at the wire** once the C SBC edge is dropped ([ADR-0003](0003-sip-rust-native-trunk.md)) |
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| Security-as-product | ▲ stronger | The single auditable boundary *is* the moat; compliance (PCI/HIPAA/TCPA) is a buying criterion |
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| In-boundary spend / abuse control | ▲ promoted | From "table-stakes service" to **constitutive** — structurally impossible for a 3-vendor stack |
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| **Data ownership** | ✦ new | Calls + training data never leave the operator's infra — the self-host wedge *and* the ML-loop fuel |
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| WASM plugin sandbox | ▼ demoted | Out of the core story. The agent **tap** is the extension point; ops-simplicity wants one binary. Softly retained as a *candidate* for community call-flow/routing plugins |
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## Consequences
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- **Positive:** sharper target than a consolidating PBX category; the wedge is a *coherent
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combination* (no-GC determinism + one auditable boundary + ops-simplicity) no one-competitor
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matches; the authoring layer can be powerful (the audience codes + has an AI pair).
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- **Negative:** narrows TAM deliberately (an engine, not a product); must hold the line against
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scope creep toward Five9-parity (the GUI-as-pure-API-client discipline is a scope guard); the
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agent brain is necessarily external, so the real-time edge lives in the **local reflexes**
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(VAD/barge-in, jitter, pacing) + the *whole* boundary, not the brain round-trip.
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## References
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- [ADR-0003](0003-sip-rust-native-trunk.md) — Rust-native trunk SIP (removes the C edge this reframe assumes)
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- [ADR-0005](0005-event-bus.md) — Valkey as bus + state store
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- [ADR-0006](0006-ingress-posture.md) — WebRTC-first ingress
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