.fusa-reqs.json

{
  "version": "1",
  "requirements": [
    {
      "id": "REQ-LIN-001",
      "title": "ValidateFrame rejects ID > 0x3F",
      "description": "ValidateFrame shall return an error when Frame.ID exceeds MaxID (0x3F).",
      "asil": "ASIL-B",
      "rationale": "SG-02: prevents an invalid identifier from being transmitted or processed.",
      "tags": ["core", "validation"]
    },
    {
      "id": "REQ-LIN-002",
      "title": "ValidateFrame rejects empty data",
      "description": "ValidateFrame shall return an error when Frame.Data has zero length.",
      "asil": "ASIL-B",
      "rationale": "SG-01: a zero-length LIN frame is malformed and has no defined wire format.",
      "tags": ["core", "validation"]
    },
    {
      "id": "REQ-LIN-003",
      "title": "ValidateFrame rejects oversized data",
      "description": "ValidateFrame shall return an error when len(Frame.Data) exceeds MaxDataLen (8).",
      "asil": "ASIL-B",
      "rationale": "SG-01: LIN 2.x limits payloads to 8 bytes; exceeding this is a protocol violation.",
      "tags": ["core", "validation"]
    },
    {
      "id": "REQ-LIN-004",
      "title": "ProtectID parity bit P0",
      "description": "ProtectID shall compute P0 = ID0 XOR ID1 XOR ID2 XOR ID4 and place it in bit 6 of the returned PID byte.",
      "asil": "ASIL-B",
      "rationale": "SG-01: P0 is mandated by LIN 2.x §2.3.1 for frame identifier error detection.",
      "tags": ["core", "pid"]
    },
    {
      "id": "REQ-LIN-005",
      "title": "ProtectID parity bit P1",
      "description": "ProtectID shall compute P1 = NOT(ID1 XOR ID3 XOR ID4 XOR ID5) and place it in bit 7 of the returned PID byte.",
      "asil": "ASIL-B",
      "rationale": "SG-01: P1 is mandated by LIN 2.x §2.3.1 for frame identifier error detection.",
      "tags": ["core", "pid"]
    },
    {
      "id": "REQ-LIN-006",
      "title": "VerifyPID accepts correct parity",
      "description": "VerifyPID shall return the raw 6-bit ID and nil error when the parity bits in the PID are correct.",
      "asil": "ASIL-B",
      "rationale": "SG-01: correct PID passes without false rejection.",
      "tags": ["core", "pid"]
    },
    {
      "id": "REQ-LIN-007",
      "title": "VerifyPID rejects incorrect parity",
      "description": "VerifyPID shall return an error when the parity bits in the supplied PID do not match those computed by ProtectID for the embedded 6-bit ID.",
      "asil": "ASIL-B",
      "rationale": "SG-01: a corrupted PID must be detected and rejected.",
      "tags": ["core", "pid"]
    },
    {
      "id": "REQ-LIN-008",
      "title": "Classic checksum covers data bytes only",
      "description": "CalcChecksum with ClassicChecksum shall sum the data bytes only (excluding PID) using inverted carry-around 8-bit addition.",
      "asil": "ASIL-B",
      "rationale": "SG-02: LIN 1.x classic checksum algorithm per LIN spec §2.3.2.",
      "tags": ["core", "checksum"]
    },
    {
      "id": "REQ-LIN-009",
      "title": "Enhanced checksum includes PID",
      "description": "CalcChecksum with EnhancedChecksum shall include the PID byte in the sum alongside the data bytes, using inverted carry-around 8-bit addition.",
      "asil": "ASIL-B",
      "rationale": "SG-02: LIN 2.x enhanced checksum algorithm per LIN spec §2.3.2.",
      "tags": ["core", "checksum"]
    },
    {
      "id": "REQ-LIN-010",
      "title": "Checksum carry-around inversion",
      "description": "CalcChecksum shall apply carry-around addition (sum > 0xFF wraps by subtracting 0xFF, not 0x100) and invert the final sum (0xFF - sum).",
      "asil": "ASIL-B",
      "rationale": "SG-02: correct carry-around is required for interoperability with LIN hardware.",
      "tags": ["core", "checksum"]
    },
    {
      "id": "REQ-LIN-011",
      "title": "Bus.Publish registers slave response",
      "description": "Bus.Publish shall register a response payload for the given frame ID so that the next SendHeader for that ID returns the registered data.",
      "asil": "ASIL-B",
      "rationale": "Core interface contract: slave response registration.",
      "tags": ["core", "interface"]
    },
    {
      "id": "REQ-LIN-012",
      "title": "Bus.Subscribe delivers matching frames",
      "description": "Bus.Subscribe shall return a channel that receives every Frame whose ID matches any supplied Filter, or all Frames when no filters are supplied.",
      "asil": "ASIL-B",
      "rationale": "Core interface contract: frame observation.",
      "tags": ["core", "interface"]
    },
    {
      "id": "REQ-LIN-013",
      "title": "MasterBus.SendHeader returns synthesised Frame",
      "description": "MasterBus.SendHeader shall trigger a frame exchange for the given ID and return the resulting Frame including correct PID and checksum.",
      "asil": "ASIL-B",
      "rationale": "Core interface contract: master-driven frame exchange.",
      "tags": ["core", "interface"]
    },
    {
      "id": "REQ-LIN-014",
      "title": "MasterBus.SendHeader returns ErrNoResponse",
      "description": "MasterBus.SendHeader shall return ErrNoResponse when no slave has registered a response for the requested frame ID.",
      "asil": "ASIL-B",
      "rationale": "Absence of a slave response is a distinct, detectable condition.",
      "tags": ["core", "interface"]
    },
    {
      "id": "REQ-LIN-015",
      "title": "ValidateFrame accepts ID = 0x3F",
      "description": "ValidateFrame shall return nil error when Frame.ID equals MaxID (0x3F), the boundary maximum.",
      "asil": "ASIL-B",
      "rationale": "SG-05: boundary condition — ID 0x3F is a valid LIN identifier and must not be falsely rejected.",
      "tags": ["core", "validation", "boundary"]
    },
    {
      "id": "REQ-LIN-016",
      "title": "ValidateFrame accepts data length 1",
      "description": "ValidateFrame shall return nil error when len(Frame.Data) equals 1, the boundary minimum.",
      "asil": "ASIL-B",
      "rationale": "SG-05: boundary condition — a 1-byte payload is the smallest valid LIN frame.",
      "tags": ["core", "validation", "boundary"]
    },
    {
      "id": "REQ-LIN-017",
      "title": "ValidateFrame accepts data length 8",
      "description": "ValidateFrame shall return nil error when len(Frame.Data) equals MaxDataLen (8), the boundary maximum.",
      "asil": "ASIL-B",
      "rationale": "SG-05: boundary condition — an 8-byte payload is the largest valid LIN frame.",
      "tags": ["core", "validation", "boundary"]
    },
    {
      "id": "REQ-LIN-018",
      "title": "ProtectID preserves lower 6 bits",
      "description": "For any id in 0x00–0x3F, (ProtectID(id) & 0x3F) shall equal id.",
      "asil": "ASIL-B",
      "rationale": "SG-01: the PID must carry the original ID in bits 0–5 so receivers can extract it.",
      "tags": ["core", "pid", "boundary"]
    },
    {
      "id": "REQ-LIN-019",
      "title": "Bus.Publish with nil removes registration",
      "description": "Bus.Publish(id, nil) shall remove any previously registered response for id; subsequent SendHeader for that id shall return ErrNoResponse.",
      "asil": "ASIL-B",
      "rationale": "Slaves must be able to withdraw a response (e.g., entering sleep mode) without restarting the bus.",
      "tags": ["core", "interface"]
    },
    {
      "id": "REQ-LIN-020",
      "title": "Bus.Subscribe with All=true delivers every frame",
      "description": "A Filter with All=true shall match every Frame regardless of ID; Bus.Subscribe with such a filter delivers all frames on the bus.",
      "asil": "ASIL-B",
      "rationale": "Bus monitoring and logging require all-frame visibility.",
      "tags": ["core", "interface", "filter"]
    },
    {
      "id": "REQ-LIN-021",
      "title": "ErrNoResponse is a non-nil sentinel error",
      "description": "ErrNoResponse shall be a non-nil error value that callers can test with errors.Is(err, lin.ErrNoResponse).",
      "asil": "ASIL-B",
      "rationale": "Callers must distinguish absent-slave from other error conditions; a sentinel enables precise error handling.",
      "tags": ["core", "error"]
    },
    {
      "id": "REQ-VIRT-001",
      "title": "New returns initialised bus",
      "description": "virtual.New shall return a Bus with an empty response table, no subscribers, and nil error.",
      "asil": "ASIL-B",
      "rationale": "Deterministic initial state required for predictable test behaviour.",
      "tags": ["virtual"]
    },
    {
      "id": "REQ-VIRT-002",
      "title": "Publish stores response",
      "description": "Publish(id, data) shall atomically store a copy of data as the response for id, replacing any prior entry.",
      "asil": "ASIL-B",
      "rationale": "A stale or partial response must never be served; atomic replacement ensures consistency.",
      "tags": ["virtual", "publish"]
    },
    {
      "id": "REQ-VIRT-003",
      "title": "Publish(nil) removes response",
      "description": "Publish(id, nil) shall remove the registered response for id so that subsequent SendHeader returns ErrNoResponse.",
      "asil": "ASIL-B",
      "rationale": "Slaves must be able to withdraw a response (e.g., during sleep mode).",
      "tags": ["virtual", "publish"]
    },
    {
      "id": "REQ-VIRT-004",
      "title": "Publish rejects ID > MaxID",
      "description": "Publish shall return an error when id > 0x3F.",
      "asil": "ASIL-B",
      "rationale": "REQ-LIN-001 boundary enforced at the transport layer.",
      "tags": ["virtual", "validation"]
    },
    {
      "id": "REQ-VIRT-005",
      "title": "Publish after Close returns error",
      "description": "Publish shall return an error when called after Close.",
      "asil": "ASIL-B",
      "rationale": "Operations on a closed bus must fail deterministically, not silently succeed.",
      "tags": ["virtual", "lifecycle"]
    },
    {
      "id": "REQ-VIRT-006",
      "title": "SendHeader computes correct PID",
      "description": "SendHeader shall set Frame.ID to the requested id and compute the PID using ProtectID before broadcasting.",
      "asil": "ASIL-B",
      "rationale": "SG-01: the PID in the synthesised frame must reflect ProtectID output.",
      "tags": ["virtual", "pid"]
    },
    {
      "id": "REQ-VIRT-007",
      "title": "SendHeader computes correct checksum",
      "description": "SendHeader shall set Frame.Checksum using CalcChecksum with the response's ChecksumType.",
      "asil": "ASIL-B",
      "rationale": "SG-02: checksum in the synthesised frame must be verifiable by subscribers.",
      "tags": ["virtual", "checksum"]
    },
    {
      "id": "REQ-VIRT-008",
      "title": "SendHeader broadcasts to subscribers",
      "description": "SendHeader shall deliver the synthesised Frame to every subscriber whose filter matches the frame ID.",
      "asil": "ASIL-B",
      "rationale": "All observers must receive the same frame data.",
      "tags": ["virtual", "broadcast"]
    },
    {
      "id": "REQ-VIRT-009",
      "title": "SendHeader returns ErrNoResponse",
      "description": "SendHeader shall return ErrNoResponse when no response is registered for the requested id.",
      "asil": "ASIL-B",
      "rationale": "REQ-LIN-014 enforced at the virtual transport layer.",
      "tags": ["virtual", "error"]
    },
    {
      "id": "REQ-VIRT-010",
      "title": "SendHeader rejects ID > MaxID",
      "description": "SendHeader shall return an error when id > 0x3F.",
      "asil": "ASIL-B",
      "rationale": "REQ-LIN-001 boundary enforced at the transport layer.",
      "tags": ["virtual", "validation"]
    },
    {
      "id": "REQ-VIRT-011",
      "title": "Subscribe exact filter isolates by ID",
      "description": "A subscriber with Filter{ID: x} shall not receive frames whose ID differs from x.",
      "asil": "ASIL-B",
      "rationale": "SG-05: cross-frame-ID leakage would cause application code to act on the wrong data.",
      "tags": ["virtual", "filter", "isolation"]
    },
    {
      "id": "REQ-VIRT-012",
      "title": "Subscribe All filter receives every frame",
      "description": "A subscriber with Filter{All: true} shall receive every frame regardless of ID.",
      "asil": "ASIL-B",
      "rationale": "Bus monitoring requires all-frames subscription.",
      "tags": ["virtual", "filter"]
    },
    {
      "id": "REQ-VIRT-013",
      "title": "Full subscriber channel drops frames without blocking",
      "description": "When a subscriber channel is full, SendHeader shall drop the frame for that subscriber rather than blocking.",
      "asil": "ASIL-B",
      "rationale": "A slow subscriber must not stall the master schedule; mirrors real LIN hardware behaviour.",
      "tags": ["virtual", "backpressure"]
    },
    {
      "id": "REQ-VIRT-014",
      "title": "Multiple subscribers each receive independently",
      "description": "When multiple subscribers match a frame, each shall receive a copy independently.",
      "asil": "ASIL-B",
      "rationale": "Independent observers must not interfere with each other.",
      "tags": ["virtual", "isolation"]
    },
    {
      "id": "REQ-VIRT-015",
      "title": "Close closes all subscriber channels",
      "description": "Close shall close every subscriber channel so that range-loops over those channels terminate.",
      "asil": "ASIL-B",
      "rationale": "Resource cleanup; prevents goroutine leaks in consumers.",
      "tags": ["virtual", "lifecycle"]
    },
    {
      "id": "REQ-VIRT-016",
      "title": "Close is idempotent",
      "description": "Close shall return nil and have no observable effect when called a second time.",
      "asil": "ASIL-B",
      "rationale": "Idempotent Close prevents double-close panics in defer chains.",
      "tags": ["virtual", "lifecycle"]
    },
    {
      "id": "REQ-VIRT-017",
      "title": "SendHeader after Close returns error",
      "description": "SendHeader shall return an error when called after Close.",
      "asil": "ASIL-B",
      "rationale": "Operations on a closed bus must fail deterministically.",
      "tags": ["virtual", "lifecycle"]
    },
    {
      "id": "REQ-VIRT-018",
      "title": "Concurrent access is data-race free",
      "description": "Publish, SendHeader, Subscribe, and Close may be called concurrently from multiple goroutines without data races.",
      "asil": "ASIL-B",
      "rationale": "Real-time LIN systems often drive the bus from one goroutine while subscribing from another; a data race would be undefined behaviour.",
      "tags": ["virtual", "concurrency"]
    },
    {
      "id": "REQ-VIRT-019",
      "title": "Publish stores a defensive copy",
      "description": "Publish shall copy the supplied data slice; subsequent mutation of the caller's slice shall not affect the stored response.",
      "asil": "ASIL-B",
      "rationale": "Shared mutable state between caller and bus would corrupt responses under concurrent use.",
      "tags": ["virtual", "safety", "copy"]
    },
    {
      "id": "REQ-LDF-001",
      "title": "Parse extracts protocol version",
      "description": "Parse shall populate DB.ProtocolVersion from the LIN_protocol_version field.",
      "asil": "ASIL-A",
      "rationale": "Protocol version determines which checksum algorithm and features apply.",
      "tags": ["ldf"]
    },
    {
      "id": "REQ-LDF-002",
      "title": "Parse extracts baud rate",
      "description": "Parse shall populate DB.Speed (kbps) from the LIN_speed field.",
      "asil": "ASIL-A",
      "rationale": "Incorrect baud rate causes all frame exchanges to fail.",
      "tags": ["ldf"]
    },
    {
      "id": "REQ-LDF-003",
      "title": "Parse extracts master node name",
      "description": "Parse shall populate DB.MasterNode from the Nodes Master declaration.",
      "asil": "ASIL-A",
      "rationale": "Master node identity is required for publisher validation.",
      "tags": ["ldf", "nodes"]
    },
    {
      "id": "REQ-LDF-004",
      "title": "Parse extracts slave node list",
      "description": "Parse shall populate DB.SlaveNodes from the Nodes Slaves declaration.",
      "asil": "ASIL-A",
      "rationale": "Slave list is used to validate frame publisher declarations.",
      "tags": ["ldf", "nodes"]
    },
    {
      "id": "REQ-LDF-005",
      "title": "Parse populates frame descriptors",
      "description": "Parse shall populate frame descriptors (name, ID, publisher, length) from the LDF Frames section.",
      "asil": "ASIL-A",
      "rationale": "SG-03: incorrect frame descriptor leads to wrong signal decoding.",
      "tags": ["ldf", "frame"]
    },
    {
      "id": "REQ-LDF-006",
      "title": "Parse populates signal-to-bit-offset mappings",
      "description": "Parse shall populate SignalRef entries (signal name and bit offset) for each frame.",
      "asil": "ASIL-A",
      "rationale": "SG-03: a wrong bit offset produces a shifted signal value.",
      "tags": ["ldf", "frame", "signal"]
    },
    {
      "id": "REQ-LDF-007",
      "title": "Parse populates signal bit width",
      "description": "Parse shall populate Signal.BitWidth from the signal definition in the LDF Signals section.",
      "asil": "ASIL-A",
      "rationale": "SG-03: wrong bit width truncates or extends the extracted value.",
      "tags": ["ldf", "signal"]
    },
    {
      "id": "REQ-LDF-008",
      "title": "Parse populates signal publisher",
      "description": "Parse shall populate Signal.Publisher from the signal definition.",
      "asil": "ASIL-A",
      "rationale": "Publisher field identifies which node is responsible for the signal value.",
      "tags": ["ldf", "signal"]
    },
    {
      "id": "REQ-LDF-009",
      "title": "Decode uses LSB-first Intel byte order",
      "description": "Decode shall extract signal values using LSB-first (Intel) bit ordering: bit 0 of the signal maps to bitOffset in the payload.",
      "asil": "ASIL-A",
      "rationale": "SG-03: wrong byte order inverts every multi-bit signal value.",
      "tags": ["ldf", "decode"]
    },
    {
      "id": "REQ-LDF-010",
      "title": "Decode returns nil for unknown frame ID",
      "description": "Decode shall return nil when the frame ID is not present in the parsed LDF.",
      "asil": "ASIL-A",
      "rationale": "Caller must be able to distinguish missing-frame from empty-signal-set.",
      "tags": ["ldf", "decode"]
    },
    {
      "id": "REQ-LDF-011",
      "title": "Parse populates schedule table entries",
      "description": "Parse shall populate schedule tables with ScheduleEntry{ID, DelayMs} from the LDF Schedule_tables section.",
      "asil": "ASIL-A",
      "rationale": "Schedule tables drive master timing; incorrect delay affects bus load.",
      "tags": ["ldf", "schedule"]
    },
    {
      "id": "REQ-LDF-012",
      "title": "Frame() returns nil for unknown ID",
      "description": "DB.Frame() shall return nil when no frame with the given ID was declared in the LDF.",
      "asil": "ASIL-A",
      "rationale": "Callers must be able to detect missing frame descriptors without panicking.",
      "tags": ["ldf", "frame"]
    },
    {
      "id": "REQ-LDF-013",
      "title": "Signal() returns nil for unknown name",
      "description": "DB.Signal() shall return nil when no signal with the given name was declared in the LDF.",
      "asil": "ASIL-A",
      "rationale": "Callers must be able to detect missing signal definitions without panicking.",
      "tags": ["ldf", "signal"]
    },
    {
      "id": "REQ-LDF-014",
      "title": "Parse does not panic on arbitrary input",
      "description": "Parse shall return a non-nil DB (possibly empty) and a non-nil error (or nil) for any input; it shall never panic.",
      "asil": "ASIL-A",
      "rationale": "SG-05: a panic on malformed LDF would crash the application; robust parsing is required.",
      "tags": ["ldf", "robustness"]
    },
    {
      "id": "REQ-LDF-015",
      "title": "Frames() returns a defensive copy",
      "description": "DB.Frames() shall return a new map; mutations to the returned map shall not affect DB's internal frame table.",
      "asil": "ASIL-A",
      "rationale": "Shared internal state could be corrupted by callers; defensive copy ensures immutability.",
      "tags": ["ldf", "copy"]
    },
    {
      "id": "REQ-MASTER-001",
      "title": "New returns non-nil Node",
      "description": "master.New shall return a non-nil *Node backed by the supplied MasterBus.",
      "asil": "ASIL-B",
      "rationale": "Callers must not need to nil-check the returned Node.",
      "tags": ["master"]
    },
    {
      "id": "REQ-MASTER-002",
      "title": "Node.SendHeader delegates to bus",
      "description": "Node.SendHeader shall call bus.SendHeader and return the Frame and error unchanged.",
      "asil": "ASIL-B",
      "rationale": "The master node must not alter or suppress the frame returned by the bus.",
      "tags": ["master"]
    },
    {
      "id": "REQ-MASTER-003",
      "title": "Run iterates schedule in order",
      "description": "Node.Run shall process schedule entries in the order they appear in the schedule table, restarting from the first entry after the last.",
      "asil": "ASIL-B",
      "rationale": "SG-01: out-of-order header transmission violates the LIN schedule contract.",
      "tags": ["master", "schedule"]
    },
    {
      "id": "REQ-MASTER-004",
      "title": "Run calls SendHeader for each slot",
      "description": "For each schedule slot, Run shall call MasterBus.SendHeader with the slot's frame ID.",
      "asil": "ASIL-B",
      "rationale": "SG-01: every slot must trigger a frame exchange.",
      "tags": ["master", "schedule"]
    },
    {
      "id": "REQ-MASTER-005",
      "title": "Run waits slot delay between exchanges",
      "description": "Run shall wait slot.DelayMs milliseconds after each frame exchange before processing the next slot.",
      "asil": "ASIL-B",
      "rationale": "Slot timing enforces bus load constraints.",
      "tags": ["master", "timing"]
    },
    {
      "id": "REQ-MASTER-006",
      "title": "Run invokes OnFrame on success",
      "description": "Run shall call the OnFrame callback with the received Frame when SendHeader succeeds.",
      "asil": "ASIL-B",
      "rationale": "Application code receives data via OnFrame; omitting the call silently drops data.",
      "tags": ["master", "callback"]
    },
    {
      "id": "REQ-MASTER-007",
      "title": "Run invokes OnError on failure",
      "description": "Run shall call the OnError callback when SendHeader returns a non-nil error.",
      "asil": "ASIL-B",
      "rationale": "Application code must be notified of absent slave responses.",
      "tags": ["master", "callback"]
    },
    {
      "id": "REQ-MASTER-008",
      "title": "Run returns on context cancellation",
      "description": "Run shall return ctx.Err() when ctx is cancelled or expires.",
      "asil": "ASIL-B",
      "rationale": "Graceful shutdown requires context propagation.",
      "tags": ["master", "lifecycle"]
    },
    {
      "id": "REQ-MASTER-009",
      "title": "Run treats an empty schedule as a no-op success",
      "description": "Run shall return success immediately (without invoking the bus) when the schedule table is empty, rather than returning an error.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.3: an empty schedule table is valid and simply disables scheduled transmission; it is not a programming error, so Run must not fail callers that have not yet configured a schedule.",
      "tags": ["master", "validation"]
    },
    {
      "id": "REQ-MASTER-010",
      "title": "SetSchedule accepts an empty schedule",
      "description": "SetSchedule shall accept a nil or zero-length slice and succeed, disabling scheduled transmission (REQ-MASTER-009) until a non-empty schedule is set.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.3: an empty schedule table is valid; SetSchedule must not reject it.",
      "tags": ["master", "validation"]
    },
    {
      "id": "REQ-MASTER-011",
      "title": "SetSchedule rejects invalid frame ID",
      "description": "SetSchedule shall return an error when any entry has ID > MaxID (0x3F).",
      "asil": "ASIL-B",
      "rationale": "REQ-LIN-001 boundary enforced at schedule configuration time.",
      "tags": ["master", "validation"]
    },
    {
      "id": "REQ-MASTER-012",
      "title": "SetSchedule stores a defensive copy",
      "description": "SetSchedule shall copy the supplied slice; subsequent mutation of the caller's slice shall not affect the active schedule.",
      "asil": "ASIL-B",
      "rationale": "Shared mutable schedule data could cause non-deterministic slot ordering.",
      "tags": ["master", "copy"]
    },
    {
      "id": "REQ-MASTER-013",
      "title": "Run continues after per-slot errors",
      "description": "Run shall continue to the next schedule slot when SendHeader returns an error (e.g., ErrNoResponse); it shall not abort the schedule.",
      "asil": "ASIL-B",
      "rationale": "A temporarily absent slave must not halt the entire LIN schedule.",
      "tags": ["master", "resilience"]
    },
    {
      "id": "REQ-SLAVE-001",
      "title": "New returns ready slave node",
      "description": "slave.New shall return a non-nil Node with no registered responses.",
      "asil": "ASIL-B",
      "rationale": "Deterministic initial state required.",
      "tags": ["slave"]
    },
    {
      "id": "REQ-SLAVE-002",
      "title": "SetResponse registers response via Publish",
      "description": "SetResponse shall call bus.Publish(id, data) and track id in its registered ID set.",
      "asil": "ASIL-B",
      "rationale": "Slave response registration must delegate to the underlying bus.",
      "tags": ["slave", "publish"]
    },
    {
      "id": "REQ-SLAVE-003",
      "title": "SetResponse(nil) removes registration",
      "description": "SetResponse(id, nil) shall call bus.Publish(id, nil) and remove id from the registered ID set.",
      "asil": "ASIL-B",
      "rationale": "Slave must be able to withdraw a response.",
      "tags": ["slave", "publish"]
    },
    {
      "id": "REQ-SLAVE-004",
      "title": "SetResponse rejects ID > MaxID",
      "description": "SetResponse shall return an error when id > 0x3F without calling bus.Publish.",
      "asil": "ASIL-B",
      "rationale": "REQ-LIN-001 boundary enforced at the slave API.",
      "tags": ["slave", "validation"]
    },
    {
      "id": "REQ-SLAVE-005",
      "title": "RegisteredIDs reflects current state",
      "description": "RegisteredIDs shall return exactly the set of IDs for which a non-nil response is currently registered.",
      "asil": "ASIL-B",
      "rationale": "Application code uses RegisteredIDs for diagnostics and health checks.",
      "tags": ["slave"]
    },
    {
      "id": "REQ-SLAVE-006",
      "title": "Subscribe delegates to bus",
      "description": "Subscribe shall delegate to bus.Subscribe and return the resulting channel and error unchanged.",
      "asil": "ASIL-B",
      "rationale": "Slave observes the bus to monitor master requests and peer responses.",
      "tags": ["slave"]
    },
    {
      "id": "REQ-SLAVE-007",
      "title": "RegisteredIDs returns empty slice when none registered",
      "description": "RegisteredIDs shall return an empty (not nil) slice when no responses are currently registered.",
      "asil": "ASIL-B",
      "rationale": "Callers must be able to use len() on the result without nil checks.",
      "tags": ["slave", "boundary"]
    },
    {
      "id": "REQ-SLAVE-008",
      "title": "SetResponse overwrites previous registration for same ID",
      "description": "When SetResponse is called for an ID that already has a registration, the new data shall replace the previous registration.",
      "asil": "ASIL-B",
      "rationale": "Slaves must be able to update responses (e.g., refreshed sensor values) without removing and re-registering.",
      "tags": ["slave", "update"]
    },
    {
      "id": "REQ-SAFETY-001",
      "title": "DataID embedded in header bytes 0-1",
      "description": "Protect shall write Config.DataID as a little-endian uint16 into bytes 0-1 of the protected payload.",
      "asil": "ASIL-B",
      "rationale": "DataID is included in the CRC computation and identifies the logical data element.",
      "tags": ["safety", "header"]
    },
    {
      "id": "REQ-SAFETY-002",
      "title": "SourceID embedded in header bytes 2-3",
      "description": "Protect shall write Config.SourceID as a little-endian uint16 into bytes 2-3 of the protected payload.",
      "asil": "ASIL-B",
      "rationale": "SourceID is included in the CRC computation and identifies the sender node.",
      "tags": ["safety", "header"]
    },
    {
      "id": "REQ-SAFETY-003",
      "title": "SequenceCounter starts at 0 and increments",
      "description": "The Protector's SequenceCounter shall start at 0 and increment by 1 with each Protect call.",
      "asil": "ASIL-B",
      "rationale": "Monotonically increasing counter enables detection of missed or replayed frames.",
      "tags": ["safety", "counter"]
    },
    {
      "id": "REQ-SAFETY-004",
      "title": "SequenceCounter embedded in header bytes 4-7",
      "description": "Protect shall write the current SequenceCounter as a little-endian uint32 into bytes 4-7.",
      "asil": "ASIL-B",
      "rationale": "SG-04: counter must be present in the wire format for gap detection.",
      "tags": ["safety", "header", "counter"]
    },
    {
      "id": "REQ-SAFETY-005",
      "title": "CRC computed over header and payload",
      "description": "Protect shall compute CRC-16/CCITT-FALSE (poly=0x1021, init=0xFFFF) over the header with CRC slot zeroed, concatenated with the payload.",
      "asil": "ASIL-B",
      "rationale": "SG-04: CRC must cover all bytes including DataID and SourceID.",
      "tags": ["safety", "crc"]
    },
    {
      "id": "REQ-SAFETY-006",
      "title": "CRC embedded in header bytes 8-9",
      "description": "Protect shall write the computed CRC as a little-endian uint16 into bytes 8-9.",
      "asil": "ASIL-B",
      "rationale": "SG-04: CRC must be transmitted so the receiver can verify it.",
      "tags": ["safety", "header", "crc"]
    },
    {
      "id": "REQ-SAFETY-007",
      "title": "Unwrap returns ErrHeaderTooShort for payload < 10 bytes",
      "description": "Unwrap shall return E2EError{Kind: ErrHeaderTooShort} when the input is shorter than 10 bytes.",
      "asil": "ASIL-B",
      "rationale": "SG-04: truncated header cannot be validated; must be rejected.",
      "tags": ["safety", "receiver", "error"]
    },
    {
      "id": "REQ-SAFETY-008",
      "title": "Unwrap detects byte corruption via CRC",
      "description": "Unwrap shall return E2EError{Kind: ErrCRCMismatch} when the recomputed CRC does not match bytes 8-9.",
      "asil": "ASIL-B",
      "rationale": "SG-04: any single-byte corruption in header or payload must be detected.",
      "tags": ["safety", "receiver", "crc"]
    },
    {
      "id": "REQ-SAFETY-009",
      "title": "Unwrap detects sequence gap",
      "description": "Unwrap shall return E2EError{Kind: ErrSequenceGap} when the received counter is not exactly lastSeq+1 (after the first received message).",
      "asil": "ASIL-B",
      "rationale": "SG-04: a gap indicates a missed or replayed frame.",
      "tags": ["safety", "receiver", "counter"]
    },
    {
      "id": "REQ-SAFETY-010",
      "title": "Unwrap returns original payload on success",
      "description": "Unwrap shall strip the 10-byte header and return a copy of the original payload when all checks pass.",
      "asil": "ASIL-B",
      "rationale": "Application code must receive the original payload unchanged.",
      "tags": ["safety", "receiver"]
    },
    {
      "id": "REQ-SAFETY-011",
      "title": "Protect/Unwrap round-trip preserves payload",
      "description": "For any payload p, Unwrap(Protect(p)) shall return a byte-for-byte copy of p with nil error when Protector and Receiver share the same Config.",
      "asil": "ASIL-B",
      "rationale": "End-to-end correctness: protection must be lossless.",
      "tags": ["safety", "roundtrip"]
    },
    {
      "id": "REQ-SAFETY-012",
      "title": "Protect output length equals 10 + len(payload)",
      "description": "The byte slice returned by Protect shall have length exactly headerSize (10) + len(payload).",
      "asil": "ASIL-B",
      "rationale": "SG-04: receivers must be able to compute the expected output length to detect truncation.",
      "tags": ["safety", "length"]
    },
    {
      "id": "REQ-SAFETY-013",
      "title": "Unwrap accepts first message with any counter value",
      "description": "A newly created Receiver shall accept the first Unwrap call regardless of the counter value in the header.",
      "asil": "ASIL-B",
      "rationale": "On cold start the receiver does not know the protector's initial counter; the first message seeds the sequence.",
      "tags": ["safety", "receiver", "counter"]
    },
    {
      "id": "REQ-SAFETY-014",
      "title": "Protect is safe for concurrent calls",
      "description": "Protect may be called concurrently from multiple goroutines; each call shall receive a unique, monotonically increasing counter value.",
      "asil": "ASIL-B",
      "rationale": "SG-04: a data race on the counter could produce duplicate counters, defeating gap detection.",
      "tags": ["safety", "concurrency"]
    },
    {
      "id": "REQ-SAFETY-015",
      "title": "Unwrap returns an independent payload copy",
      "description": "The payload returned by Unwrap shall be a fresh copy; mutations to it shall not affect future Unwrap calls or internal state.",
      "asil": "ASIL-B",
      "rationale": "Shared payload memory between receiver and caller could corrupt subsequent receives.",
      "tags": ["safety", "copy"]
    },
    {
      "id": "REQ-SEOOC-001",
      "title": "Integrating system provides physical LIN layer",
      "description": "The system integrating go-LIN shall provide a correct LIN physical layer (transceiver, break detection, bit timing). go-LIN operates above the physical layer.",
      "asil": "ASIL-B",
      "rationale": "Physical-layer faults are outside go-LIN scope; must be addressed by the integrating system.",
      "tags": ["seooc", "assumption"]
    },
    {
      "id": "REQ-SEOOC-002",
      "title": "Integrating system calls ValidateFrame on external data",
      "description": "The integrating system shall call ValidateFrame on any frame received from external hardware before passing it to go-LIN APIs.",
      "asil": "ASIL-B",
      "rationale": "go-LIN validates at API boundaries; raw hardware data must be validated by the caller first.",
      "tags": ["seooc", "assumption"]
    },
    {
      "id": "REQ-SEOOC-003",
      "title": "Integrating system validates frame ID semantics",
      "description": "The integrating system shall verify that a received frame ID corresponds to the intended actuator or sensor before acting on the payload.",
      "asil": "ASIL-B",
      "rationale": "go-LIN delivers frames as received; semantic validation is the application's responsibility.",
      "tags": ["seooc", "assumption"]
    },
    {
      "id": "REQ-SEOOC-004",
      "title": "Integration: virtual bus delivers E2E payload intact",
      "description": "When Protect(payload) is published on the virtual bus and retrieved via SendHeader + Unwrap, the result shall equal payload with nil error.",
      "asil": "ASIL-B",
      "rationale": "End-to-end integration test of virtual transport + safety layer together.",
      "tags": ["seooc", "integration"]
    },
    {
      "id": "REQ-SEOOC-005",
      "title": "Integration: master-slave round-trip via virtual bus",
      "description": "A slave registered via slave.SetResponse shall have its payload returned by master.Node.SendHeader via the virtual bus.",
      "asil": "ASIL-B",
      "rationale": "Verifies the master-slave integration contract using the virtual transport.",
      "tags": ["seooc", "integration"]
    },
    {
      "id": "REQ-SEOOC-006",
      "title": "Integration: LDF schedule IDs are valid",
      "description": "LDF schedule table entries shall reference only frame IDs that appear in the Frames section and are within 0x00–0x3F.",
      "asil": "ASIL-A",
      "rationale": "A schedule entry referencing an undeclared ID would cause ErrNoResponse on every cycle.",
      "tags": ["seooc", "integration", "ldf"]
    },
    {
      "id": "REQ-SEOOC-007",
      "title": "Integrating system handles ErrNoResponse safely",
      "description": "The integrating system shall handle lin.ErrNoResponse without propagating the absence of a slave as a safety-critical output change.",
      "asil": "ASIL-B",
      "rationale": "A missing slave response is an operational condition; the application must decide the safe-state action.",
      "tags": ["seooc", "assumption"]
    },
    {
      "id": "REQ-SEOOC-008",
      "title": "Integrating system routes safety-critical frames through safety package",
      "description": "The integrating system shall apply safety.Protect/Unwrap to all frame payloads classified as safety-critical (ASIL >= ASIL-B).",
      "asil": "ASIL-B",
      "rationale": "go-LIN provides E2E protection but does not enforce which frames use it; the application must apply it to safety-relevant data.",
      "tags": ["seooc", "assumption"]
    },
    {
      "id": "REQ-SEOOC-009",
      "title": "Integrating system provides monotonic clock for timing",
      "description": "The integrating system shall provide a monotonic clock with at least 1 ms resolution for LIN schedule slot timing.",
      "asil": "ASIL-B",
      "rationale": "go-LIN uses time.After for slot delays; clock accuracy below 1 ms will cause schedule timing jitter.",
      "tags": ["seooc", "assumption", "timing"]
    },
    {
      "id": "REQ-ADAPT-001",
      "title": "Adapt returns a LIN relay.Node",
      "description": "Adapt shall return a non-nil relay.Node whose Protocol method reports relay.LIN.",
      "asil": "ASIL-B",
      "rationale": "RELAY §10.3/§13.7: the protocol-agnostic application layer must observe the correct protocol tag to route LIN traffic.",
      "tags": ["adapt", "relay"]
    },
    {
      "id": "REQ-ADAPT-002",
      "title": "linNode.Send publishes payload for a valid frame ID",
      "description": "linNode.Send shall publish msg.Payload as the slave response for the frame ID parsed from msg.ID when the ID is in range 0-63.",
      "asil": "ASIL-B",
      "rationale": "RELAY §10.3: the adapter egress path must faithfully forward application payloads onto the LIN bus.",
      "tags": ["adapt", "relay"]
    },
    {
      "id": "REQ-ADAPT-003",
      "title": "linNode.Send rejects an out-of-range frame ID",
      "description": "linNode.Send shall return a non-nil error and shall not publish when msg.ID is not a decimal string in range 0-63.",
      "asil": "ASIL-B",
      "rationale": "SG-05: an invalid identifier supplied through the adapter must not be transmitted.",
      "tags": ["adapt", "relay", "validation"]
    },
    {
      "id": "REQ-ADAPT-004",
      "title": "linNode.Subscribe converts frames to relay.Message",
      "description": "linNode.Subscribe shall return a channel that yields one relay.Message per received frame, each carrying the frame's canonical ToMessage() conversion.",
      "asil": "ASIL-B",
      "rationale": "RELAY §10.5: the adapter ingress path must deliver every received frame to the application as a canonical envelope.",
      "tags": ["adapt", "relay"]
    },
    {
      "id": "REQ-ADAPT-005",
      "title": "linNode.Close closes the underlying bus",
      "description": "linNode.Close shall close the wrapped Bus and return its error unchanged.",
      "asil": "ASIL-B",
      "rationale": "RELAY §6 lifecycle: closing the node must release the underlying transport so no further frames are processed.",
      "tags": ["adapt", "relay", "lifecycle"]
    },
    {
      "id": "REQ-MOCK-001",
      "title": "mock.New returns a MasterBus-satisfying bus",
      "description": "mock.New shall return a non-nil bus that satisfies lin.MasterBus (Publish, Subscribe, SendHeader, SetSchedule, Close).",
      "asil": "ASIL-B",
      "rationale": "RELAY §7 rule 4 / §13.7: a mandatory mock transport must implement the full bus contract so applications can be tested without hardware.",
      "tags": ["mock", "relay"]
    },
    {
      "id": "REQ-RELAY-001",
      "title": "Protocol enum values are defined and stable",
      "description": "relay::Protocol shall define CAN=1, DDS=2, LIN=3, MQTT=4, RCP=5, SOMEIP=6 as stable integer values matching RELAY spec v1.11 §3.",
      "asil": "ASIL-B",
      "rationale": "Protocol values are wire-format identifiers; changing them breaks cross-language interop.",
      "tags": ["relay", "protocol"]
    },
    {
      "id": "REQ-RELAY-002",
      "title": "Protocol enum is an int-backed enum class",
      "description": "relay::Protocol shall be an enum class backed by int to prevent implicit integer promotion and enable type-safe switching.",
      "asil": "ASIL-B",
      "rationale": "Type safety prevents accidental protocol ID confusion at compile time.",
      "tags": ["relay", "protocol"]
    },
    {
      "id": "REQ-RELAY-003",
      "title": "to_string(Protocol) returns canonical name",
      "description": "relay::to_string(Protocol p) shall return the canonical uppercase protocol name (e.g., 'LIN', 'CAN') and 'unknown' for unrecognised values.",
      "asil": "ASIL-B",
      "rationale": "RELAY §3.1: canonical names are used in log output and diagnostic fields.",
      "tags": ["relay", "protocol"]
    },
    {
      "id": "REQ-RELAY-004",
      "title": "Version struct has major/minor/patch fields",
      "description": "relay::Version shall provide int fields major, minor, and patch with equality comparison.",
      "asil": "ASIL-B",
      "rationale": "RELAY §4: version negotiation requires structured version comparison.",
      "tags": ["relay", "version"]
    },
    {
      "id": "REQ-RELAY-005",
      "title": "Version::to_string returns 'major.minor.patch'",
      "description": "Version::to_string() shall return a string formatted as '<major>.<minor>.<patch>'.",
      "asil": "ASIL-B",
      "rationale": "RELAY §4.1: canonical version string format for diagnostics and conformance checks.",
      "tags": ["relay", "version"]
    },
    {
      "id": "REQ-RELAY-006",
      "title": "Message struct fields: protocol, version, id, payload, timestamp, seq, meta",
      "description": "relay::Message shall provide fields: Protocol protocol, Version version, std::string id, std::vector<uint8_t> payload, system_clock::time_point timestamp, uint64_t seq, unordered_map<string,string> meta.",
      "asil": "ASIL-B",
      "rationale": "RELAY §5: canonical message envelope for all protocol bindings.",
      "tags": ["relay", "message"]
    },
    {
      "id": "REQ-RELAY-007",
      "title": "Message id is a string (protocol-specific format)",
      "description": "Message::id shall be a std::string whose format is defined per protocol binding (e.g., decimal integer for LIN, hex for CAN).",
      "asil": "ASIL-B",
      "rationale": "RELAY §5.2: string ID allows each protocol to use its native identifier notation.",
      "tags": ["relay", "message"]
    },
    {
      "id": "REQ-RELAY-008",
      "title": "Errc::closed is error code 1",
      "description": "relay::Errc::closed shall have integer value 1.",
      "asil": "ASIL-B",
      "rationale": "RELAY §9.1: stable error code values required for cross-language compatibility.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-009",
      "title": "Errc::not_connected is error code 2",
      "description": "relay::Errc::not_connected shall have integer value 2.",
      "asil": "ASIL-B",
      "rationale": "RELAY §9.1: stable error code values.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-010",
      "title": "Errc::timeout is error code 3",
      "description": "relay::Errc::timeout shall have integer value 3.",
      "asil": "ASIL-B",
      "rationale": "RELAY §9.1: stable error code values.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-011",
      "title": "Errc::payload_too_large is error code 4",
      "description": "relay::Errc::payload_too_large shall have integer value 4.",
      "asil": "ASIL-B",
      "rationale": "RELAY §9.1: stable error code values.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-012",
      "title": "Errc is an int-backed enum class",
      "description": "relay::Errc shall be an enum class backed by int, compatible with std::error_code.",
      "asil": "ASIL-B",
      "rationale": "Enables implicit std::error_code construction via is_error_code_enum specialisation.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-013",
      "title": "INode abstract interface: protocol(), send(), subscribe(), close()",
      "description": "relay::INode shall declare pure virtual methods: protocol() const noexcept, send(Message), subscribe(vector<SubscriberOption>), and close().",
      "asil": "ASIL-B",
      "rationale": "RELAY §6: INode is the mandatory base interface for all protocol adapters.",
      "tags": ["relay", "interface"]
    },
    {
      "id": "REQ-RELAY-014",
      "title": "ICaller extends INode with call()",
      "description": "relay::ICaller shall extend INode with a call(Message req, milliseconds timeout) method returning pair<Message, error_code>.",
      "asil": "ASIL-B",
      "rationale": "RELAY §6.4: synchronous request/response pattern for RPC-style protocols.",
      "tags": ["relay", "interface"]
    },
    {
      "id": "REQ-RELAY-015",
      "title": "BackPressurePolicy enum: DropNewest=0, DropOldest=1, Block=2",
      "description": "relay::BackPressurePolicy shall define DropNewest=0, DropOldest=1, Block=2.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8: backpressure policies allow callers to choose between latency and reliability tradeoffs.",
      "tags": ["relay", "backpressure"]
    },
    {
      "id": "REQ-RELAY-016",
      "title": "SubscriberConfig holds channel depth, backpressure, event_id, topic_name",
      "description": "relay::SubscriberConfig shall hold: int chan_depth, BackPressurePolicy back_pressure, uint32_t event_id, string topic_name.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.1: subscriber configuration captures all protocol-agnostic subscriber settings.",
      "tags": ["relay", "subscriber"]
    },
    {
      "id": "REQ-RELAY-017",
      "title": "SubscriberOption is a std::function<void(SubscriberConfig&)>",
      "description": "relay::SubscriberOption shall be typedef'd as std::function<void(SubscriberConfig&)>.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.2: functional option pattern allows composable subscriber configuration.",
      "tags": ["relay", "subscriber"]
    },
    {
      "id": "REQ-RELAY-018",
      "title": "apply_options() folds options into SubscriberConfig",
      "description": "relay::apply_options(opts) shall apply each option in order to a default SubscriberConfig and return the result.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.3: apply_options is the canonical way to construct a SubscriberConfig from options.",
      "tags": ["relay", "subscriber"]
    },
    {
      "id": "REQ-RELAY-019",
      "title": "SubscriberConfig::effective_depth returns default when chan_depth is 0",
      "description": "effective_depth(default_depth) shall return chan_depth when chan_depth > 0, else default_depth.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.1: zero chan_depth means 'use implementation default'; explicit non-zero overrides.",
      "tags": ["relay", "subscriber"]
    },
    {
      "id": "REQ-RELAY-020",
      "title": "kSpecVersion constant equals '1.11'",
      "description": "relay::kSpecVersion shall be a constexpr const char* equal to '1.11'.",
      "asil": "ASIL-B",
      "rationale": "RELAY §2: spec version constant enables runtime conformance checking.",
      "tags": ["relay", "version"]
    },
    {
      "id": "REQ-RELAY-021",
      "title": "error_category() and make_error_code(Errc) are noexcept",
      "description": "relay::error_category() and make_error_code(Errc) shall be declared noexcept and return stable singleton/error_code values.",
      "asil": "ASIL-B",
      "rationale": "std::error_code comparison requires stable category identity; noexcept prevents unexpected termination.",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-022",
      "title": "is_error_code_enum<relay::Errc> specialisation enables implicit construction",
      "description": "std::is_error_code_enum<relay::Errc> shall be specialised to true_type to enable implicit relay::Errc -> std::error_code conversion.",
      "asil": "ASIL-B",
      "rationale": "Enables idiomatic std::error_code usage: if (err == relay::Errc::closed) {...}",
      "tags": ["relay", "error"]
    },
    {
      "id": "REQ-RELAY-023",
      "title": "HealthStatus enum: OK=0, Degraded=1, Down=2",
      "description": "relay::HealthStatus shall define OK=0, Degraded=1, Down=2.",
      "asil": "ASIL-B",
      "rationale": "RELAY §11: standardised health status values for monitoring integrations.",
      "tags": ["relay", "health"]
    },
    {
      "id": "REQ-RELAY-024",
      "title": "Health struct holds status and details string",
      "description": "relay::Health shall hold HealthStatus status and std::string details.",
      "asil": "ASIL-B",
      "rationale": "RELAY §11.1: health details provide diagnostic context beyond the status enum.",
      "tags": ["relay", "health"]
    },
    {
      "id": "REQ-RELAY-025",
      "title": "IHealthProvider declares virtual health() const",
      "description": "relay::IHealthProvider shall declare a pure virtual health() const method returning Health.",
      "asil": "ASIL-B",
      "rationale": "RELAY §11: optional capability interface for nodes that support health reporting.",
      "tags": ["relay", "health"]
    },
    {
      "id": "REQ-RELAY-026",
      "title": "Metrics struct fields: write_count, deliver_count, drop_count, bytes_written, bytes_delivered, error_count",
      "description": "relay::Metrics shall hold uint64_t fields for write_count, deliver_count, drop_count, bytes_written, bytes_delivered, error_count.",
      "asil": "ASIL-B",
      "rationale": "RELAY §12: metrics fields provide observability for bus throughput and reliability.",
      "tags": ["relay", "metrics"]
    },
    {
      "id": "REQ-RELAY-027",
      "title": "IMetricsProvider declares virtual metrics() const",
      "description": "relay::IMetricsProvider shall declare a pure virtual metrics() const method returning Metrics.",
      "asil": "ASIL-B",
      "rationale": "RELAY §12: optional capability interface for nodes that expose metrics.",
      "tags": ["relay", "metrics"]
    },
    {
      "id": "REQ-RELAY-028",
      "title": "IDrainer declares virtual close_with_drain(timeout)",
      "description": "relay::IDrainer shall declare a pure virtual close_with_drain(std::chrono::milliseconds timeout) method returning std::error_code.",
      "asil": "ASIL-B",
      "rationale": "RELAY §13: drain pattern ensures in-flight messages are delivered before close.",
      "tags": ["relay", "lifecycle"]
    },
    {
      "id": "REQ-RELAY-029",
      "title": "Metrics bytes_written and bytes_delivered track total payload bytes",
      "description": "bytes_written shall accumulate the total byte count of all payloads sent; bytes_delivered shall accumulate the total byte count of all payloads delivered to subscribers.",
      "asil": "ASIL-B",
      "rationale": "RELAY §12.1: byte counters enable bandwidth monitoring and leak detection.",
      "tags": ["relay", "metrics"]
    },
    {
      "id": "REQ-RELAY-051",
      "title": "with_channel_depth(n) option sets chan_depth",
      "description": "relay::with_channel_depth(n) shall return a SubscriberOption that sets SubscriberConfig::chan_depth to n.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.2.1: channel depth tuning option for subscriber configuration.",
      "tags": ["relay", "subscriber", "option"]
    },
    {
      "id": "REQ-RELAY-056",
      "title": "with_back_pressure(policy) option sets back_pressure",
      "description": "relay::with_back_pressure(p) shall return a SubscriberOption that sets SubscriberConfig::back_pressure to p.",
      "asil": "ASIL-B",
      "rationale": "RELAY §8.2.2: backpressure policy option for subscriber configuration.",
      "tags": ["relay", "subscriber", "option"]
    },
    {
      "id": "REQ-RELAY-059",
      "title": "parse_protocol() throws on unknown string; try_parse_protocol() returns false",
      "description": "relay::parse_protocol(s) shall throw std::invalid_argument for unknown protocol strings. relay::try_parse_protocol(s, out) shall return false and leave out unchanged for unknown strings.",
      "asil": "ASIL-B",
      "rationale": "RELAY §3.2: robust protocol string parsing with two variants for exception/error-code styles.",
      "tags": ["relay", "protocol"]
    },
    {
      "id": "REQ-CLI-001",
      "title": "version command prints tool and spec version",
      "description": "The CLI `version` command shall print the tool and spec version as JSON (or text with --format text).",
      "asil": "QM",
      "rationale": "RELAY §11.1: mandatory version command for conformance self-reporting.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-CLI-002",
      "title": "capabilities command prints supported protocols and commands",
      "description": "The CLI `capabilities` command shall print supported protocols, transports, commands and interfaces as JSON.",
      "asil": "QM",
      "rationale": "RELAY §11.2/§12: mandatory capabilities self-report.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-CLI-003",
      "title": "status command prints health status",
      "description": "The CLI `status` command shall print the health status as JSON (or text with --format text).",
      "asil": "QM",
      "rationale": "RELAY §11.1: mandatory status command.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-CLI-004",
      "title": "CLI exits 2 on invalid arguments",
      "description": "The CLI shall exit with code 2 and write an error name to stderr on invalid or unknown arguments.",
      "asil": "QM",
      "rationale": "RELAY §11.3: standardised CLI exit codes.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-CLI-005",
      "title": "CLI --format flag selects text or json output",
      "description": "Commands accepting --format shall support 'text' and 'json' and reject other values with exit code 2.",
      "asil": "QM",
      "rationale": "RELAY §11.1: --format text|json handling.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-CLI-006",
      "title": "convert command bridges lin.Frame to relay.Message JSON",
      "description": "The CLI `convert` command shall read a lin.Frame JSON from stdin, validate it, and write the corresponding relay.Message JSON to stdout, writing the sentinel error name to stderr on failure.",
      "asil": "QM",
      "rationale": "RELAY §11.2: cross-protocol conversion command.",
      "tags": ["cli"]
    },
    {
      "id": "REQ-SEC-013",
      "title": "Bounded channel try_send rejects when full",
      "description": "Chan::try_send shall return SendResult::Full when the channel is at capacity rather than growing unboundedly, bounding memory under back-pressure.",
      "asil": "ASIL-B",
      "rationale": "SG-04: no unbounded memory growth under load / denial-of-service resistance.",
      "tags": ["security", "channel"]
    }
  ]
}