diff --git a/docs/library-decisions/_template.md b/docs/library-decisions/_template.md
index 1f16bb0..f25d9a7 100644
--- a/docs/library-decisions/_template.md
+++ b/docs/library-decisions/_template.md
@@ -6,6 +6,7 @@ decision: approved | rejected
 date: <YYYY-MM-DD>
 deciders: [<author>, ...]
 adr: adr-NNN | null
+lastRevalidated: null
 filter-results:
   license: <SPDX id>
   types: native | "@types/<x>" | none
@@ -15,6 +16,7 @@ filter-results:
   eu-residency: ok | n/a | self-hostable | fail
   cve-scan: clean | "<advisory-id>" | fail
   named-consumer: pass | fail
+  socketRisk: clean | flagged | <arbitrary-string>
 verification-commands:
   - <literal command that produced each filter result>
 accepted-cves: []
@@ -84,6 +86,26 @@ Answer: "Who calls this code path today, or who is blocked waiting for it?"
 Hypothetical future callers are not consumers. This filter is the direct
 response to the 2026-05-14 OpenAPI near-miss (ADR-022 §Context).
 
+## Filter: socketRisk
+
+<!-- Result: clean | flagged | <arbitrary-string> -->
+
+Run `socket npm:report <package>` (or check socket.dev) for supply-chain
+risk signals. `clean` = no issues detected. `flagged` = one or more high- or
+critical-severity signals (requires explicit risk-acceptance note here before
+approval). An arbitrary string records the specific risk label returned by the
+Socket CLI (e.g. `"obfuscated-code"`, `"install-script"`). The `lastRevalidated`
+frontmatter field is set to the ISO date of the most recent re-run.
+
+## Field: lastRevalidated
+
+<!-- Value: YYYY-MM-DD | null -->
+
+ISO 8601 date of the last time the Socket supply-chain scan (and any other
+time-sensitive filter) was re-run against the current installed version.
+`null` = never revalidated since initial adoption (acceptable for fresh traces).
+Updated automatically by the weekly revalidation cron (Story 05).
+
 ## Prompt: replaces
 
 <!-- Required: answer in either direction with justification -->
diff --git a/scripts/library-decisions/schema.mjs b/scripts/library-decisions/schema.mjs
index 5b7f5a6..eb37ad7 100644
--- a/scripts/library-decisions/schema.mjs
+++ b/scripts/library-decisions/schema.mjs
@@ -17,6 +17,7 @@ const filterResultsSchema = z
     "eu-residency": z.enum(["ok", "n/a", "self-hostable", "fail"]),
     "cve-scan": z.string().min(1),
     "named-consumer": z.enum(["pass", "fail"]),
+    socketRisk: z.union([z.literal("clean"), z.literal("flagged"), z.string()]),
   })
   .strict();
 
@@ -29,6 +30,7 @@ export const traceSchema = z
     date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/, "date must be YYYY-MM-DD"),
     deciders: z.array(z.string()),
     adr: z.string().nullable(),
+    lastRevalidated: z.string().nullable(),
     "filter-results": filterResultsSchema,
     "verification-commands": z.array(z.string()),
     "accepted-cves": z.array(z.string()).optional(),
diff --git a/scripts/library-decisions/schema.test.mjs b/scripts/library-decisions/schema.test.mjs
index 8dc05e8..2b285e3 100644
--- a/scripts/library-decisions/schema.test.mjs
+++ b/scripts/library-decisions/schema.test.mjs
@@ -14,6 +14,7 @@ function validRaw(overrides = {}) {
     date: "2026-05-14",
     deciders: ["alice"],
     adr: null,
+    lastRevalidated: null,
     "filter-results": {
       license: "MIT",
       types: "native",
@@ -23,6 +24,7 @@ function validRaw(overrides = {}) {
       "eu-residency": "ok",
       "cve-scan": "clean",
       "named-consumer": "pass",
+      socketRisk: "clean",
     },
     "verification-commands": ["pnpm audit --audit-level=moderate"],
     ...overrides,
@@ -43,6 +45,7 @@ decision: approved
 date: 2026-05-14
 deciders: [alice, bob]
 adr: null
+lastRevalidated: null
 filter-results:
   license: MIT
   types: native
@@ -52,6 +55,7 @@ filter-results:
   eu-residency: ok
   cve-scan: clean
   named-consumer: pass
+  socketRisk: clean
 verification-commands:
   - pnpm audit --audit-level=moderate`;
 
@@ -125,6 +129,59 @@ describe("validateTrace > rejection cases", () => {
       /unrecognized_keys|Unrecognized key/i,
     );
   });
+
+  test("missing socketRisk in filter-results fails validation", () => {
+    const raw = validRaw();
+    delete raw["filter-results"].socketRisk;
+    assert.throws(() => validateTrace(raw), /invalid_type|Required/i);
+  });
+});
+
+describe("validateTrace > socketRisk", () => {
+  test('socketRisk "clean" round-trips', () => {
+    const result = validateTrace(validRaw());
+    assert.equal(result["filter-results"].socketRisk, "clean");
+  });
+
+  test('socketRisk "flagged" round-trips', () => {
+    const raw = validRaw({
+      "filter-results": {
+        ...validRaw()["filter-results"],
+        socketRisk: "flagged",
+      },
+    });
+    assert.equal(validateTrace(raw)["filter-results"].socketRisk, "flagged");
+  });
+
+  test("socketRisk arbitrary string round-trips", () => {
+    const raw = validRaw({
+      "filter-results": {
+        ...validRaw()["filter-results"],
+        socketRisk: "obfuscated-code",
+      },
+    });
+    assert.equal(
+      validateTrace(raw)["filter-results"].socketRisk,
+      "obfuscated-code",
+    );
+  });
+});
+
+describe("validateTrace > lastRevalidated", () => {
+  test("lastRevalidated null is valid", () => {
+    assert.equal(
+      validateTrace(validRaw({ lastRevalidated: null })).lastRevalidated,
+      null,
+    );
+  });
+
+  test("lastRevalidated ISO date string is valid", () => {
+    assert.equal(
+      validateTrace(validRaw({ lastRevalidated: "2026-05-14" }))
+        .lastRevalidated,
+      "2026-05-14",
+    );
+  });
 });
 
 describe("parseFrontmatter", () => {