diff --git a/crates/ledger-cli/tests/defects.rs b/crates/ledger-cli/tests/defects.rs
new file mode 100644
index 0000000..cc3fe43
--- /dev/null
+++ b/crates/ledger-cli/tests/defects.rs
@@ -0,0 +1,265 @@
+//! The re-audit's engineering mirror (plan P10; `docs/runbooks/re-audit.md`):
+//! every defect the 2026-10-16 audit found (1 to 20), P0 (21, 22) and P3
+//! (23, 24) has a named regression test somewhere in the workspace, and the
+//! runbook names only tools and commands that exist.
+//!
+//! The list below is the single place that says which test stands guard for
+//! which defect. A test renamed or deleted fails here, so a defect's
+//! reproduction cannot be lost quietly. This proves the tests exist, are
+//! real `#[test]`s and are not ignored; that they pass is `cargo test`'s
+//! job (the runbook's step 4 runs them by name).
+//!
+//! SOURCE: plan/served.md 8.0 ("defect n") and P10 step 2.
+
+use std::path::{Path, PathBuf};
+
+fn root() -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("../..")
+        .canonicalize()
+        .unwrap()
+}
+
+fn read(rel: &str) -> String {
+    std::fs::read_to_string(root().join(rel)).unwrap_or_else(|e| panic!("{rel}: {e}"))
+}
+
+/// `(defect, test name, file)`. Defect 2 is closed by D-12 and D-47 (the
+/// rule it now shows is that a reversal needs no receipt of its own);
+/// defect 20 (the migration scripts) was retired at the cutover and is
+/// checked separately below.
+const DEFECTS: [(u32, &str, &str); 23] = [
+    (
+        1,
+        "defect1_two_member_llc_first_year_regression",
+        "crates/ledger-core/tests/spec_cash_flow.rs",
+    ),
+    (
+        2,
+        "a_reversal_needs_no_receipt_of_its_own",
+        "crates/ledger-cli/tests/drafts.rs",
+    ),
+    (
+        3,
+        "get_receipt_default_has_text_and_no_bytes",
+        "crates/ledger-cli/tests/evidence.rs",
+    ),
+    (
+        4,
+        "same_bytes_one_record_many_links",
+        "crates/ledger-store/tests/attachments.rs",
+    ),
+    (
+        5,
+        "a_draft_waits_for_its_receipt_and_posts",
+        "crates/ledger-cli/tests/drafts.rs",
+    ),
+    (
+        6,
+        "digest_since_seq_is_posting_time",
+        "crates/ledger-cli/tests/drafts.rs",
+    ),
+    (
+        7,
+        "the_readme_lists_what_the_iif_writes_differently",
+        "crates/ledger-package/tests/package.rs",
+    ),
+    (
+        8,
+        "add_account_warns_without_tax_category_defect_8",
+        "crates/ledger-cli/tests/spec_tax_policy.rs",
+    ),
+    (
+        9,
+        "defect9_a_new_schedule_spreads_by_the_day",
+        "crates/ledger-core/tests/schedules.rs",
+    ),
+    (
+        10,
+        "annotations_replay_and_project",
+        "crates/ledger-store/tests/attachments.rs",
+    ),
+    (
+        11,
+        "defect11_the_directory_shows_a_members_tin_last4",
+        "crates/ledger-cli/tests/spec_vault.rs",
+    ),
+    (
+        12,
+        "payment_methods_round_trip_and_classify_payments",
+        "crates/ledger-cli/tests/spec_1099.rs",
+    ),
+    (
+        13,
+        "four_contributed_devices_each_take_the_lower_of_value_and_basis",
+        "crates/ledger-core/tests/spec_asset_basis.rs",
+    ),
+    (
+        14,
+        "defect14_party_totals_take_a_basis",
+        "crates/ledger-cli/tests/spec_party_totals.rs",
+    ),
+    (
+        15,
+        "rename_account_end_to_end_defect_15",
+        "crates/ledger-cli/tests/mcp_journeys.rs",
+    ),
+    (
+        16,
+        "one_default_period_everywhere_defect_16",
+        "crates/ledger-cli/tests/mcp_journeys.rs",
+    ),
+    (
+        17,
+        "the_audit_odd_cent_never_piles_up_across_closes",
+        "crates/ledger-core/tests/odd_cent.rs",
+    ),
+    (
+        18,
+        "undecided_is_not_not_reportable",
+        "crates/ledger-core/tests/form1099.rs",
+    ),
+    (
+        19,
+        "no_tool_takes_a_path",
+        "crates/ledger-mcp/src/server_tests.rs",
+    ),
+    (
+        21,
+        "as_of_package_iif_stops_at_as_of",
+        "crates/ledger-package/tests/package.rs",
+    ),
+    (
+        22,
+        "defect22_depreciation_through_mid_final_month_is_prorated_not_plugged",
+        "crates/ledger-core/tests/spec_assets_payroll.rs",
+    ),
+    (
+        23,
+        "a_vendor_marked_no_1099_is_not_undecided",
+        "crates/ledger-cli/tests/spec_1099.rs",
+    ),
+    (
+        24,
+        "defect24_an_accrual_through_another_liability_counts_once",
+        "crates/ledger-core/tests/spec_party_totals.rs",
+    ),
+];
+
+/// Defects 1 to 24 each have a named test that exists, is a test, and is
+/// not ignored (defect 20 is the retired scripts, below).
+#[test]
+fn every_defect_reproduction_is_a_named_test() {
+    let mut covered: Vec<u32> = DEFECTS.iter().map(|d| d.0).collect();
+    covered.push(20);
+    covered.sort_unstable();
+    assert_eq!(
+        covered,
+        (1..=24).collect::<Vec<u32>>(),
+        "a defect is missing"
+    );
+
+    let mut missing = Vec::new();
+    for (defect, name, file) in DEFECTS {
+        let text = read(file);
+        let lines: Vec<&str> = text.lines().collect();
+        let needle = format!("fn {name}(");
+        let Some(at) = lines.iter().position(|l| {
+            l.trim_start().starts_with(&needle)
+                || l.trim_start().starts_with(&format!("pub {needle}"))
+        }) else {
+            missing.push(format!("defect {defect}: no `fn {name}` in {file}"));
+            continue;
+        };
+        // The attributes and doc lines above the function, up to the
+        // previous blank line or item.
+        let above: String = lines[at.saturating_sub(8)..at].join("\n");
+        let in_proptest = text.contains("proptest!");
+        if !above.contains("#[test]") && !in_proptest {
+            missing.push(format!(
+                "defect {defect}: `{name}` in {file} is not a #[test]"
+            ));
+        }
+        if above.contains("#[ignore") {
+            missing.push(format!("defect {defect}: `{name}` in {file} is ignored"));
+        }
+    }
+    assert!(missing.is_empty(), "{}", missing.join("\n"));
+}
+
+/// Defect 20, the migration scripts, was retired at the cutover: there is
+/// no tool for them, and none may come back as a way past the journal.
+/// The defect 19 mirror (`import_local_file` and every path parameter) is
+/// `no_tool_takes_a_path` above.
+#[test]
+fn defect_20_no_migration_tool_exists() {
+    let scopes = read("crates/ledger-mcp/src/scopes.rs");
+    for line in scopes.lines().filter(|l| l.contains("(\"books.")) {
+        for banned in [
+            "migrate",
+            "import_local_file",
+            "import_sheet",
+            "verify_sheet",
+        ] {
+            assert!(!line.contains(banned), "a retired tool is back: {line}");
+        }
+    }
+}
+
+/// The runbook names only tools and commands that exist: each
+/// `books.<name>` is in the scopes table (the 8.0.3 list of tools), each
+/// `wanderbooks <command>` is a command `main.rs` dispatches, and each
+/// test file it names is a file.
+#[test]
+fn the_re_audit_runbook_names_only_what_exists() {
+    let runbook = read("docs/runbooks/re-audit.md");
+    let scopes = read("crates/ledger-mcp/src/scopes.rs");
+    let main = read("crates/ledger-cli/src/main.rs");
+
+    let mut tools = Vec::new();
+    let mut rest = runbook.as_str();
+    while let Some(i) = rest.find("books.") {
+        let tail = &rest[i..];
+        let end = tail
+            .find(|c: char| !(c.is_ascii_alphanumeric() || c == '_' || c == '.'))
+            .unwrap_or(tail.len());
+        let name = tail[..end].trim_end_matches('.');
+        // Prose such as "books.start's" ends at the apostrophe; a bare
+        // "books." (the company's books followed by a full stop) is not a name.
+        if name.len() > "books.".len() && !tools.contains(&name.to_string()) {
+            tools.push(name.to_string());
+        }
+        rest = &tail[end.max(1)..];
+    }
+    assert!(
+        tools.len() > 20,
+        "the runbook should name its tools: {tools:?}"
+    );
+    let unknown: Vec<&String> = tools
+        .iter()
+        .filter(|t| !scopes.contains(&format!("(\"{t}\"")))
+        .collect();
+    assert!(
+        unknown.is_empty(),
+        "tools the runbook names that do not exist: {unknown:?}"
+    );
+
+    for cmd in ["gui", "connect"] {
+        if runbook.contains(&format!("wanderbooks {cmd}")) {
+            assert!(main.contains(&format!("\"{cmd}\"")), "no command {cmd}");
+        }
+    }
+    assert!(
+        runbook.contains("wanderbooks gui"),
+        "step 6 names the viewer"
+    );
+
+    for step in 1..=8 {
+        assert!(
+            runbook.contains(&format!("## Step {step}.")),
+            "the runbook lost step {step}"
+        );
+    }
+    // The runbook must not point at the data root or tell anyone to read it.
+    assert!(!runbook.contains("wanderbooks.v"), "names a database file");
+}
diff --git a/docs/testing.md b/docs/testing.md
index db1c715..a643a37 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -3922,3 +3922,33 @@ export gate (`cpa_audit_standing`'s four conditions and its feature test,
 the `refuse`/`warn` split, the reason's trim); `audit_items` in Needs
 attention (the declared test, the attested set, the last-ended fiscal
 year, the three year conditions).
+
+## P10: the re-audit runbook's mirror
+
+`docs/runbooks/re-audit.md` is the owner's acceptance, run on his books
+through the MCP alone. What CI can check of it is in
+`crates/ledger-cli/tests/defects.rs`:
+
+- `every_defect_reproduction_is_a_named_test`: a table of `(defect, test
+  name, file)` for the 2026-10-16 audit's defects 1 to 19, P0's 21 and 22
+  and P3's 23 and 24 (23 rows); each named function exists in its file, is
+  a `#[test]` (or inside `proptest!`) and is not `#[ignore]`d. Defect 2 is
+  closed by D-12 and D-47, so its row is the rule as it now stands
+  (`a_reversal_needs_no_receipt_of_its_own`).
+- `defect_20_no_migration_tool_exists`: defect 20 (the migration scripts)
+  was retired at the cutover; no tool of that kind is in the scopes table.
+- `the_re_audit_runbook_names_only_what_exists`: every `books.<name>` in
+  the runbook is in `crates/ledger-mcp/src/scopes.rs`, the commands it
+  names are dispatched by `main.rs`, and its eight steps are present.
+
+The mirror proves the tests exist, not that they pass; the runbook's step 4
+runs them by name. No CI job was added: the test runs in the existing
+`check` job's `cargo test --workspace`. The run itself (a counted
+attestation on every receipt and entry, the two CPA packages equal, the
+sign-off) is the owner's and has no CI equivalent.
+
+**For P12 (mutation targets):** the `DEFECTS` table's file/name lookup (a
+`starts_with` on `fn <name>(`; the `#[test]`/`#[ignore]` window of eight
+lines above it) and the scopes-line scan in `defect_20_*`. A mutant that
+widens the window or drops the `ignore` check survives only if no ignored
+or untested name is in the table; the table is the oracle.