diff --git a/.github/workflows/fuzz-cadence.yml b/.github/workflows/fuzz-cadence.yml
new file mode 100644
index 00000000..5d412df7
--- /dev/null
+++ b/.github/workflows/fuzz-cadence.yml
@@ -0,0 +1,69 @@
+# Soft / nightly sustained fuzz cadence for C07 L67 beyond PR fuzz-smoke.
+# PR path: hermetic SelfCheck only (keeps default PR CI fast).
+# Schedule / dispatch: 120s per target + crash artifact upload on failure.
+# continue-on-error: soft gate; does not block merges.
+name: fuzz cadence
+
+on:
+  schedule:
+    - cron: "57 4 * * *" # nightly 04:57 UTC (offset from miri/loom soft jobs)
+  workflow_dispatch:
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  fuzz-selfcheck:
+    name: soft fuzz · SelfCheck
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - name: fuzz cadence SelfCheck
+        shell: pwsh
+        run: ./scripts/fuzz-cadence-check.ps1 -SelfCheck
+
+  fuzz-sustained:
+    name: soft fuzz · sustained 120s
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    continue-on-error: true
+    # cargo-fuzz requires nightly. rust-toolchain.toml pins stable, so force
+    # nightly via RUSTUP_TOOLCHAIN. Clear inherited RUSTFLAGS. Pin gnu host
+    # target — cargo-fuzz otherwise may pick musl, which cannot use ASAN.
+    env:
+      RUSTFLAGS: ""
+      RUSTUP_TOOLCHAIN: nightly
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@4be7066ada62dd38de10e7b70166bc74ed198c30 # nightly for fuzz
+        with:
+          toolchain: nightly
+          components: rust-src
+          targets: x86_64-unknown-linux-gnu
+      - name: install cargo-fuzz
+        uses: taiki-e/install-action@e28ac56891501ddb0600608470dbe94544964ed4 # cargo-fuzz
+        with:
+          tool: cargo-fuzz
+      - name: sustained fuzz OKF parse and roundtrip (120s)
+        run: cargo +nightly fuzz run okf_roundtrip --sanitizer address --target x86_64-unknown-linux-gnu -- -max_total_time=120
+      - name: sustained fuzz JSONL ingest parse (120s)
+        run: cargo +nightly fuzz run jsonl_ingest --sanitizer address --target x86_64-unknown-linux-gnu -- -max_total_time=120
+      - name: upload fuzz crash artifacts
+        if: failure()
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        with:
+          name: fuzz-crash-artifacts
+          path: fuzz/artifacts/
+          if-no-files-found: ignore
+          retention-days: 14
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 1be5a70d..ea413182 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -30,8 +30,10 @@ The CI repeat is a short detection signal; it does not replace a root-cause fix.
 Use the [flake tracker](docs/ops/flake-tracker.md) to record confirmed flakes
 and any temporary quarantine.
 
-The `fuzz-smoke` CI job runs the committed OKF corpus for 10 seconds. Longer
-local campaigns use `cargo fuzz run okf_roundtrip`.
+The `fuzz-smoke` CI job runs the committed corpus for 10 seconds per target.
+Soft sustained cadence (nightly / dispatch, 120 s / target) and crash corpus
+triage live in [`docs/ops/fuzz-cadence.md`](docs/ops/fuzz-cadence.md). Longer
+local campaigns use `cargo fuzz run okf_roundtrip` (or `jsonl_ingest`).
 
 ## Native WebView accessibility smoke
 
diff --git a/docs/ops/fuzz-cadence.md b/docs/ops/fuzz-cadence.md
new file mode 100644
index 00000000..86a525b0
--- /dev/null
+++ b/docs/ops/fuzz-cadence.md
@@ -0,0 +1,90 @@
+# Fuzz cadence (C07 L67)
+
+SessionLedger ships two `cargo-fuzz` targets with a **seeded corpus** and a
+**blocking PR smoke** (`ci.yml` → `fuzz-smoke`, 10 seconds per target). This
+page is the SSOT for the **sustained / soft longer cadence** beyond that smoke:
+nightly campaigns, crash artifact triage, and how to keep PR CI fast.
+
+Related: [`test-pyramid.md`](test-pyramid.md) (pyramid layer),
+[`fuzz/`](../../fuzz/), [`.github/workflows/ci.yml`](../../.github/workflows/ci.yml)
+(`fuzz-smoke`), [`.github/workflows/fuzz-cadence.yml`](../../.github/workflows/fuzz-cadence.yml).
+
+## Cadence map
+
+| Lane | Duration | When | Gate |
+|------|----------|------|------|
+| PR smoke | 10 s / target | every PR / push via `ci.yml` → `fuzz-smoke` | **blocking** |
+| Sustained soft | 120 s / target | nightly schedule + `workflow_dispatch` | **soft** (`continue-on-error`) |
+| Local campaign | operator-chosen | maintainer machine | manual |
+
+PR smoke stays short on purpose. Sustained runs **do not** join the default PR
+required-check surface — they live in `fuzz-cadence.yml` and stay soft so a
+flaky libFuzzer campaign cannot block merges.
+
+## Targets and corpora
+
+| Target | Seed corpus | Exercises |
+|--------|-------------|-----------|
+| `okf_roundtrip` | `fuzz/corpus/okf_roundtrip/` | OKF parse + roundtrip invariants |
+| `jsonl_ingest` | `fuzz/corpus/jsonl_ingest/` | JSONL ingest parse paths |
+
+## Soft sustained workflow
+
+[`fuzz-cadence.yml`](../../.github/workflows/fuzz-cadence.yml) is **non-blocking**
+(`continue-on-error: true`). It:
+
+1. Runs `scripts/fuzz-cadence-check.ps1 -SelfCheck` (docs/workflow/path anchors).
+2. On schedule / `workflow_dispatch` only (skipped on `pull_request`): runs each
+   target for `-max_total_time=120` with ASAN on `x86_64-unknown-linux-gnu`
+   (same toolchain pins as `fuzz-smoke`).
+3. On failure, uploads `fuzz/artifacts/` for crash corpus triage.
+
+Schedule: nightly UTC (offset from miri/loom soft jobs) + `workflow_dispatch`.
+`pull_request` only exercises the hermetic SelfCheck job so default PR CI is
+not lengthened by the 120 s campaigns.
+
+## Crash corpus triage
+
+When a sustained (or local) run finds a crash, libFuzzer writes under
+`fuzz/artifacts/<target>/` (for example `crash-*`). Triage steps:
+
+1. Download the workflow artifact `fuzz-crash-artifacts` (or copy the local
+   `fuzz/artifacts/` tree).
+2. Reproduce with the failing input:
+   `cargo +nightly fuzz run <target> fuzz/artifacts/<target>/<crash-file>`.
+3. Minimize when useful:
+   `cargo +nightly fuzz tmin <target> fuzz/artifacts/<target>/<crash-file>`.
+4. Reduce to a focused regression (unit/property test or a small corpus seed
+   under `fuzz/corpus/<target>/`) and open a fix PR.
+5. Do **not** commit raw unbounded crash dumps or corpus growth from CI without
+   review — keep seeds small and intentional.
+
+## Done gates
+
+| Gate | Status | Evidence |
+|------|--------|----------|
+| Fuzz cadence SelfCheck | **done** | `scripts/fuzz-cadence-check.ps1 -SelfCheck` (+ `tests/fuzz_cadence.rs`) |
+| Soft sustained fuzz CI | **done** | `.github/workflows/fuzz-cadence.yml` (`continue-on-error`, 120 s / target) |
+| PR `fuzz-smoke` (10 s) | **done** | `.github/workflows/ci.yml` (unchanged; stays blocking + short) |
+| Auto corpus promotion from CI crashes | **unpaid** | Triage remains maintainer-driven (see above) |
+
+## Machine verification (SelfCheck)
+
+Hermetic docs + path + workflow anchors (no `cargo fuzz`, no network):
+
+```powershell
+pwsh ./scripts/fuzz-cadence-check.ps1 -SelfCheck
+```
+
+## Local sustained campaign
+
+Nightly toolchain + `cargo-fuzz` (same flags as soft CI):
+
+```powershell
+$env:CARGO_TARGET_DIR = Join-Path $PWD "target-w32-c07-fuzz"
+cargo +nightly fuzz run okf_roundtrip --sanitizer address --target x86_64-unknown-linux-gnu -- -max_total_time=120
+cargo +nightly fuzz run jsonl_ingest --sanitizer address --target x86_64-unknown-linux-gnu -- -max_total_time=120
+```
+
+On Windows hosts without ASAN/gnu, drop `--sanitizer` / `--target` and use a
+shorter local time budget; prefer Linux (or the soft CI job) for ASAN campaigns.
diff --git a/docs/ops/test-pyramid.md b/docs/ops/test-pyramid.md
index 3fa03b18..15dad231 100644
--- a/docs/ops/test-pyramid.md
+++ b/docs/ops/test-pyramid.md
@@ -134,8 +134,10 @@ Structure-aware fuzzing via `cargo-fuzz` (nightly + ASAN on Linux CI).
 | [`fuzz/fuzz_targets/okf_roundtrip.rs`](../../fuzz/fuzz_targets/okf_roundtrip.rs) | `fuzz/corpus/okf_roundtrip/` | OKF parse + roundtrip invariants |
 | [`fuzz/fuzz_targets/jsonl_ingest.rs`](../../fuzz/fuzz_targets/jsonl_ingest.rs) | `fuzz/corpus/jsonl_ingest/` | JSONL ingest parse paths |
 
-PR smoke: `ci.yml` → `fuzz-smoke` (10 seconds per target). Longer campaigns
-remain operator/nightly work — no sustained fuzz gate on every merge.
+PR smoke: `ci.yml` → `fuzz-smoke` (10 seconds per target). Sustained soft
+cadence (120 s / target, crash artifact triage): [`fuzz-cadence.md`](fuzz-cadence.md)
++ `.github/workflows/fuzz-cadence.yml` (`continue-on-error`; skipped on PR so
+default CI stays fast). No blocking sustained fuzz gate on every merge.
 
 Local (nightly toolchain + `cargo-fuzz` installed):
 
diff --git a/scripts/fuzz-cadence-check.ps1 b/scripts/fuzz-cadence-check.ps1
new file mode 100644
index 00000000..0d213639
--- /dev/null
+++ b/scripts/fuzz-cadence-check.ps1
@@ -0,0 +1,146 @@
+<#
+.SYNOPSIS
+  Machine-check fuzz cadence SSOT anchors (C07 L67).
+
+.DESCRIPTION
+  Verifies docs/ops/fuzz-cadence.md documents sustained soft fuzz beyond PR
+  smoke, and that the fuzz-cadence workflow, fuzz targets/corpus, and this
+  script stay wired. Hermetic: no cargo-fuzz, no network.
+
+  Does not claim blocking sustained fuzz or automatic corpus promotion.
+
+.PARAMETER SelfCheck
+  Explicit docs/path smoke (CI unit proof). Same checks as the default path.
+
+.EXAMPLE
+  pwsh ./scripts/fuzz-cadence-check.ps1 -SelfCheck
+#>
+[CmdletBinding()]
+param(
+    [switch]$SelfCheck
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$repoRoot = Split-Path -Parent $PSScriptRoot
+$docPath = Join-Path $repoRoot "docs/ops/fuzz-cadence.md"
+$workflowPath = Join-Path $repoRoot ".github/workflows/fuzz-cadence.yml"
+$ciPath = Join-Path $repoRoot ".github/workflows/ci.yml"
+$selfPath = Join-Path $repoRoot "scripts/fuzz-cadence-check.ps1"
+$okfTarget = Join-Path $repoRoot "fuzz/fuzz_targets/okf_roundtrip.rs"
+$jsonlTarget = Join-Path $repoRoot "fuzz/fuzz_targets/jsonl_ingest.rs"
+$okfCorpus = Join-Path $repoRoot "fuzz/corpus/okf_roundtrip/minimal.json"
+$jsonlCorpus = Join-Path $repoRoot "fuzz/corpus/jsonl_ingest/two_sessions.jsonl"
+
+function Assert-File {
+    param(
+        [Parameter(Mandatory = $true)][string]$Path,
+        [Parameter(Mandatory = $true)][string]$Label
+    )
+    if (-not (Test-Path -LiteralPath $Path -PathType Leaf)) {
+        throw "Missing $Label at '$Path'."
+    }
+}
+
+function Write-Check {
+    param([string]$Label, [bool]$Ok)
+    $mark = if ($Ok) { "PASS" } else { "FAIL" }
+    Write-Host "  [$mark] $Label"
+    return $Ok
+}
+
+function Test-DocContains {
+    param(
+        [Parameter(Mandatory = $true)][string]$Doc,
+        [Parameter(Mandatory = $true)][string]$Needle,
+        [Parameter(Mandatory = $true)][string]$Label,
+        [string]$Context = "docs/ops/fuzz-cadence.md"
+    )
+    $ok = $Doc.Contains($Needle)
+    [void](Write-Check -Label $Label -Ok $ok)
+    if (-not $ok) {
+        throw "$Context missing required anchor: '$Needle'"
+    }
+}
+
+Write-Host "Fuzz cadence check (C07 L67)"
+if ($SelfCheck) {
+    Write-Host "Mode: SelfCheck (docs + workflow + corpus anchors; no cargo-fuzz / no network)"
+}
+
+Assert-File -Path $docPath -Label "fuzz cadence doc"
+Assert-File -Path $workflowPath -Label "fuzz-cadence workflow"
+Assert-File -Path $ciPath -Label "ci.yml"
+Assert-File -Path $selfPath -Label "fuzz cadence check script"
+Assert-File -Path $okfTarget -Label "okf_roundtrip fuzz target"
+Assert-File -Path $jsonlTarget -Label "jsonl_ingest fuzz target"
+Assert-File -Path $okfCorpus -Label "okf_roundtrip corpus seed"
+Assert-File -Path $jsonlCorpus -Label "jsonl_ingest corpus seed"
+
+$doc = Get-Content -LiteralPath $docPath -Raw
+$workflow = Get-Content -LiteralPath $workflowPath -Raw
+$ci = Get-Content -LiteralPath $ciPath -Raw
+
+Write-Host "Fuzz cadence doc anchors:"
+Test-DocContains -Doc $doc -Needle "Fuzz cadence (C07 L67)" `
+    -Label "doc heading"
+Test-DocContains -Doc $doc -Needle "scripts/fuzz-cadence-check.ps1" `
+    -Label "SelfCheck script reference"
+Test-DocContains -Doc $doc -Needle "-SelfCheck" `
+    -Label "SelfCheck invocation"
+Test-DocContains -Doc $doc -Needle "Fuzz cadence SelfCheck | **done**" `
+    -Label "SelfCheck gate marked done"
+Test-DocContains -Doc $doc -Needle "fuzz-cadence.yml" `
+    -Label "fuzz-cadence workflow reference"
+Test-DocContains -Doc $doc -Needle "continue-on-error" `
+    -Label "soft continue-on-error note"
+Test-DocContains -Doc $doc -Needle "max_total_time=120" `
+    -Label "sustained 120s budget"
+Test-DocContains -Doc $doc -Needle "fuzz-smoke" `
+    -Label "PR fuzz-smoke reference"
+Test-DocContains -Doc $doc -Needle "## Crash corpus triage" `
+    -Label "crash corpus triage section"
+Test-DocContains -Doc $doc -Needle "fuzz/artifacts/" `
+    -Label "crash artifacts path"
+Test-DocContains -Doc $doc -Needle "Auto corpus promotion from CI crashes | **unpaid**" `
+    -Label "auto corpus promotion unpaid gate"
+Test-DocContains -Doc $doc -Needle "okf_roundtrip" `
+    -Label "okf_roundtrip target"
+Test-DocContains -Doc $doc -Needle "jsonl_ingest" `
+    -Label "jsonl_ingest target"
+
+Write-Host "Workflow soft-gate anchors:"
+if ($workflow -notmatch 'continue-on-error:\s*true') {
+    throw "fuzz-cadence.yml must set continue-on-error: true (soft gate)."
+}
+[void](Write-Check -Label "workflow continue-on-error: true" -Ok $true)
+
+if ($workflow -notmatch 'max_total_time=120') {
+    throw "fuzz-cadence.yml must run sustained fuzz with -max_total_time=120."
+}
+[void](Write-Check -Label "workflow max_total_time=120" -Ok $true)
+
+if ($workflow -notmatch 'github\.event_name != ''pull_request''') {
+    throw "fuzz-cadence.yml must skip sustained job on pull_request (keep PR CI fast)."
+}
+[void](Write-Check -Label "sustained job skips pull_request" -Ok $true)
+
+if ($workflow -notmatch 'fuzz-crash-artifacts') {
+    throw "fuzz-cadence.yml must upload fuzz-crash-artifacts on failure."
+}
+[void](Write-Check -Label "workflow crash artifact upload" -Ok $true)
+
+if ($workflow -notmatch 'okf_roundtrip' -or $workflow -notmatch 'jsonl_ingest') {
+    throw "fuzz-cadence.yml must exercise okf_roundtrip and jsonl_ingest."
+}
+[void](Write-Check -Label "workflow exercises both fuzz targets" -Ok $true)
+
+Write-Host "PR smoke stays short:"
+if ($ci -notmatch 'max_total_time=10') {
+    throw "ci.yml fuzz-smoke must keep -max_total_time=10 (do not slow PR CI here)."
+}
+[void](Write-Check -Label "ci.yml fuzz-smoke max_total_time=10" -Ok $true)
+
+Write-Host "Fuzz cadence SelfCheck passed"
+exit 0
diff --git a/tests/fuzz_cadence.rs b/tests/fuzz_cadence.rs
new file mode 100644
index 00000000..fa4ade54
--- /dev/null
+++ b/tests/fuzz_cadence.rs
@@ -0,0 +1,33 @@
+//! Hermetic `SelfCheck` for fuzz cadence SSOT anchors (C07 L67).
+//!
+//! Local: `pwsh ./scripts/fuzz-cadence-check.ps1 -SelfCheck`
+//! Does not run cargo-fuzz — safe under default Windows `cargo test`.
+
+use std::path::PathBuf;
+use std::process::Command;
+
+fn repo_root() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+}
+
+#[test]
+fn fuzz_cadence_doc_self_check_validates_anchors() {
+    let script = repo_root().join("scripts/fuzz-cadence-check.ps1");
+    assert!(script.is_file(), "expected fuzz cadence check script at {}", script.display());
+
+    let output = Command::new("pwsh")
+        .args(["-NoProfile", "-File", script.to_str().expect("utf-8 script path"), "-SelfCheck"])
+        .output()
+        .unwrap_or_else(|error| panic!("failed to spawn pwsh for SelfCheck: {error}"));
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(
+        output.status.success(),
+        "fuzz-cadence-check.ps1 -SelfCheck failed\nstdout:\n{stdout}\nstderr:\n{stderr}"
+    );
+    assert!(
+        stdout.contains("Fuzz cadence SelfCheck passed"),
+        "expected SelfCheck success line, got:\n{stdout}"
+    );
+}