{
  "planPath": "docs/plans/2026-07-24-mqtt-sparkplug-driver.md",
  "note": "Wave 2 MQTT/Sparkplug B driver. Two phases both in-scope: P1 (plain MQTT, Tasks 0-14) is a complete shippable milestone; P2 (Sparkplug B ingest, Tasks 15-26) builds on it and every P2 task chains back to Task 14. Write-through (NCMD/DCMD/plain publish) is DEFERRED (design P3). Hard rules: Task 0 (MQTTnet-5/net10 restore+build under central pinning with transitive pinning OFF) is the mandatory FIRST gate. Hand-roll Tahu proto over ONE MQTTnet-5 client (NOT SparkplugNet \u2014 its MQTTnet-4.x transitive pin collides with the repo's deliberately-OFF CentralPackageTransitivePinning). DriverType string is 'Mqtt' everywhere (grep-enforced). Enum-serialization trap: every JSON seam uses shared JsonSerializerOptions with JsonStringEnumConverter. Fixtures enforce TLS+auth, never anonymous/public-broker. Google.Protobuf (3.34.1) + Grpc.Tools (2.76.0) already pinned; MQTTnet is the one new pin. High-risk tasks: 4 (hand-rolled reconnect loop), 18/19 (alias/seq state-machine components), 21 (the full 3.6 ingest matrix).",
  "tasks": [
    {
      "id": 0,
      "subject": "Task 0 (P1): Dependency-validation spike \u2014 MQTTnet-5 pin + net10 restore/build under central pinning",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": []
    },
    {
      "id": 1,
      "subject": "Task 1 (P1): .Contracts enums + MqttDriverOptions DTO (name-serialized)",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [],
      "blockedBy": [
        0
      ]
    },
    {
      "id": 2,
      "subject": "Task 2 (P1): .Contracts MqttTagDefinition + MqttEquipmentTagParser (plain, strict enum)",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        1
      ]
    },
    {
      "id": 3,
      "subject": "Task 3 (P1): .Driver + MqttConnection connect/TLS/auth (bounded deadline)",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        1
      ]
    },
    {
      "id": 4,
      "subject": "Task 4 (P1): MqttConnection hand-rolled reconnect loop (backoff + resubscribe)",
      "status": "completed",
      "classification": "high-risk",
      "parallelizableWith": [],
      "blockedBy": [
        3
      ]
    },
    {
      "id": 5,
      "subject": "Task 5 (P1): LastValueCache + IReadable (per-ref no-data)",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [
        6
      ],
      "blockedBy": [
        3
      ]
    },
    {
      "id": 6,
      "subject": "Task 6 (P1): ISubscribable plain topic subscribe\u2192OnDataChange + retained seed",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [
        5
      ],
      "blockedBy": [
        2,
        4
      ]
    },
    {
      "id": 7,
      "subject": "Task 7 (P1): MqttDriver shell \u2014 IDriver + authored-only ITagDiscovery (Once) + probe interface",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        5,
        6
      ]
    },
    {
      "id": 8,
      "subject": "Task 8 (P1): MqttDriverProbe CONNECT handshake",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [
        10
      ],
      "blockedBy": [
        3
      ]
    },
    {
      "id": 9,
      "subject": "Task 9 (P1): Factory + DriverTypeNames.Mqtt + Host factory/probe registration",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        7,
        8
      ]
    },
    {
      "id": 10,
      "subject": "Task 10 (P1): .Browser bespoke #-observation browser (passive)",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [
        8
      ],
      "blockedBy": [
        2
      ]
    },
    {
      "id": 11,
      "subject": "Task 11 (P1): Register MqttDriverBrowser (bespoke-first for Mqtt)",
      "status": "completed",
      "classification": "trivial",
      "parallelizableWith": [
        12
      ],
      "blockedBy": [
        10
      ]
    },
    {
      "id": 12,
      "subject": "Task 12 (P1): Typed AdminUI editor + validator (plain shape)",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [
        11
      ],
      "blockedBy": [
        2
      ]
    },
    {
      "id": 13,
      "subject": "Task 13 (P1): Mosquitto+JSON-publisher fixture (TLS+auth) + env-gated live suite",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        9
      ]
    },
    {
      "id": 14,
      "subject": "Task 14 (P1): Live /run verify on docker-dev \u2014 P1 MILESTONE COMPLETE",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [],
      "blockedBy": [
        9,
        11,
        12,
        13
      ]
    },
    {
      "id": 15,
      "subject": "Task 15 (P2): Vendor Tahu sparkplug_b.proto + Grpc.Tools codegen",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        14
      ]
    },
    {
      "id": 16,
      "subject": "Task 16 (P2): SparkplugCodec decode + golden payload vectors",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [
        17
      ],
      "blockedBy": [
        15
      ]
    },
    {
      "id": 17,
      "subject": "Task 17 (P2): SparkplugTopic parse/format + SparkplugDataType.ToDriverDataType map",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [
        16
      ],
      "blockedBy": [
        15
      ]
    },
    {
      "id": 18,
      "subject": "Task 18 (P2): BirthCache + AliasTable \u2014 bind-by-name, rebuild-per-birth",
      "status": "completed",
      "classification": "high-risk",
      "parallelizableWith": [
        19
      ],
      "blockedBy": [
        16,
        17
      ]
    },
    {
      "id": 19,
      "subject": "Task 19 (P2): SequenceTracker seq-gap + bdSeq death-tie",
      "status": "completed",
      "classification": "high-risk",
      "parallelizableWith": [
        18
      ],
      "blockedBy": [
        16,
        17
      ]
    },
    {
      "id": 20,
      "subject": "Task 20 (P2): RebirthRequester NCMD encode",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [],
      "blockedBy": [
        16
      ]
    },
    {
      "id": 21,
      "subject": "Task 21 (P2): Sparkplug ingest state machine \u2014 the 3.6 matrix",
      "status": "completed",
      "classification": "high-risk",
      "parallelizableWith": [],
      "blockedBy": [
        18,
        19,
        20
      ]
    },
    {
      "id": 22,
      "subject": "Task 22 (P2): ITagDiscovery UntilStable + IRediscoverable (rediscover-on-DBIRTH)",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        21
      ]
    },
    {
      "id": 23,
      "subject": "Task 23 (P2): Sparkplug browser tree + AttributesAsync + scoped RequestRebirthAsync",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [
        24
      ],
      "blockedBy": [
        20,
        21
      ]
    },
    {
      "id": 24,
      "subject": "Task 24 (P2): AdminUI editor Sparkplug mode shape + validator",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [
        23
      ],
      "blockedBy": [
        12,
        17
      ]
    },
    {
      "id": 25,
      "subject": "Task 25 (P2): C# edge-node simulator fixture + 3.6 live matrix",
      "status": "completed",
      "classification": "standard",
      "parallelizableWith": [],
      "blockedBy": [
        21,
        22,
        23
      ]
    },
    {
      "id": 26,
      "subject": "Task 26 (P2): Live /run verify Sparkplug \u2014 P2 COMPLETE",
      "status": "completed",
      "classification": "small",
      "parallelizableWith": [],
      "blockedBy": [
        23,
        24,
        25
      ]
    }
  ],
  "lastUpdated": "2026-07-27",
  "closureNote": "All 27 tasks shipped, both phases live-gated. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
}