diff --git a/packages/spec/src/__tests__/profile-registration.test.ts b/packages/spec/src/__tests__/profile-registration.test.ts
new file mode 100644
index 000000000..234ae52a2
--- /dev/null
+++ b/packages/spec/src/__tests__/profile-registration.test.ts
@@ -0,0 +1,178 @@
+/**
+ * checkProfileRegistration — what the gateway's append-only profile
+ * registration route (bus #2621) runs before inserting a row.
+ */
+import { describe, it, expect } from "vitest";
+
+import { checkProfileRegistration } from "../evidence/profile-registration.js";
+import { computeMeasurementProfileDigest, type MeasurementProfileV1 } from "../evidence/measurement-profile.js";
+
+const CAMERA = "dev-camera";
+const VERSION = "PhotoCameraAdapter-1.0.0";
+
+function cameraProfile(): MeasurementProfileV1 {
+  return {
+    profileVersion: 1,
+    profileId: "pcc://profiles/test/inspected-page/v1",
+    outcome: {
+      capabilityType: "document-printing",
+      statement: "The page was printed and a separate camera inspected it.",
+      objectIdentity: { kind: "documentHash", value: "sha256:" + "c".repeat(64) },
+    },
+    device: {
+      deviceId: CAMERA,
+      kind: "camera",
+      adapterType: "photo",
+      permittedAdapterVersions: [VERSION],
+      permittedFirmwareVersions: [VERSION],
+    },
+    measurement: { method: "optical-capture", quantity: "printed-page-image", unit: "none", sampling: { minSamples: 1 } },
+    capture: { startCondition: "execution_completed", endCondition: "open", coverage: { policy: "one-shot", minFraction: 1 } },
+    calibration: { required: false },
+    interpretation: { evidenceTypeIds: ["capture.photo_nonced"], acceptanceLevel: "inspected_output", onDeviceFailure: "reject" },
+    simulationProhibited: true,
+    witnesses: { requiredRoles: [], independentOfClaimant: false },
+    onMissingData: "reject",
+    onContradiction: "reject",
+  };
+}
+
+const request = (profile: unknown, over: Partial<{ capabilityType: string; deviceId: string; claimedDigest: string }> = {}) => ({
+  capabilityType: "document-printing",
+  deviceId: CAMERA,
+  profile,
+  ...over,
+});
+
+const codes = (r: ReturnType<typeof checkProfileRegistration>) => (r.ok ? [] : r.problems.map((p) => p.code));
+
+describe("profile registration — accepts a registrable profile", () => {
+  it("disjoint adapter and firmware pins are registrable: each pin is checked against its own evidence field", () => {
+    const p = cameraProfile();
+    p.device.permittedFirmwareVersions = ["cam-fw-2.1.0"];
+    expect(checkProfileRegistration(request(p)).ok).toBe(true);
+  });
+
+  it("returns the server-computed digest", () => {
+    const p = cameraProfile();
+    const r = checkProfileRegistration(request(p));
+    expect(r.ok).toBe(true);
+    if (r.ok) expect(r.profileDigest).toBe(computeMeasurementProfileDigest(p));
+  });
+
+  it("accepts a client digest only when it equals the server's", () => {
+    const p = cameraProfile();
+    expect(checkProfileRegistration(request(p, { claimedDigest: computeMeasurementProfileDigest(p) })).ok).toBe(true);
+  });
+});
+
+describe("profile registration — refuses what could never govern the device's evidence", () => {
+  it("an invalid profile", () => {
+    const p = { ...cameraProfile(), simulationProhibited: false };
+    expect(codes(checkProfileRegistration(request(p)))).toEqual(["profile-invalid"]);
+  });
+
+  it("a non-object never throws", () => {
+    expect(codes(checkProfileRegistration(request("not a profile")))).toEqual(["profile-invalid"]);
+    expect(codes(checkProfileRegistration(request(null)))).toEqual(["profile-invalid"]);
+  });
+
+  it("a profile naming another device than the row it would be stored under", () => {
+    expect(codes(checkProfileRegistration(request(cameraProfile(), { deviceId: "dev-other" })))).toEqual(["device-mismatch"]);
+  });
+
+  it("a profile for another capability type", () => {
+    expect(codes(checkProfileRegistration(request(cameraProfile(), { capabilityType: "cnc-milling" })))).toEqual([
+      "capability-type-mismatch",
+    ]);
+  });
+
+  it("a profile with a term admission cannot evaluate (refused now, not discovered at settlement)", () => {
+    const p = cameraProfile();
+    p.measurement.tolerance = { comparator: ">=", target: 0.9 };
+    const r = checkProfileRegistration(request(p));
+    expect(codes(r)).toEqual(["unverifiable-term"]);
+  });
+
+  it("a version pin written as a pattern (pins are exact strings)", () => {
+    const p = cameraProfile();
+    p.device.permittedFirmwareVersions = ["*-unpinned-pilot"];
+    const r = checkProfileRegistration(request(p));
+    expect(codes(r)).toEqual(["unverifiable-term"]);
+    expect(r.ok ? "" : r.problems[0]!.detail).toContain("exact strings");
+  });
+
+  it("a device kind no evidence source can carry", () => {
+    const p = cameraProfile();
+    p.device.kind = "machine";
+    expect(codes(checkProfileRegistration(request(p)))).toEqual(["unverifiable-term"]);
+  });
+
+  it("a primitive id that is not active in the vocabulary", () => {
+    const p = cameraProfile();
+    p.interpretation.evidenceTypeIds = ["capture.no_such_primitive"];
+    expect(codes(checkProfileRegistration(request(p)))).toEqual(["unverifiable-term"]);
+  });
+
+  it("a profile with an unknown term is invalid, so it can never be committed", () => {
+    const p = { ...cameraProfile(), extraTerm: "never evaluated" };
+    expect(codes(checkProfileRegistration(request(p)))).toEqual(["profile-invalid"]);
+  });
+
+  it("a client digest that is not the digest of the submitted profile", () => {
+    const p = cameraProfile();
+    const other = cameraProfile();
+    other.measurement.sampling.minSamples = 2;
+    expect(codes(checkProfileRegistration(request(p, { claimedDigest: computeMeasurementProfileDigest(other) })))).toEqual([
+      "digest-mismatch",
+    ]);
+  });
+
+  it("a client digest in the sha256: evidence-event family", () => {
+    const p = cameraProfile();
+    const tagged = `sha256:${computeMeasurementProfileDigest(p).slice(2)}`;
+    expect(codes(checkProfileRegistration(request(p, { claimedDigest: tagged })))).toEqual(["digest-mismatch"]);
+  });
+
+  it("reports every problem at once, so an operator can fix the profile in one pass", () => {
+    const p = cameraProfile();
+    p.measurement.tolerance = { comparator: ">=", target: 0.9 };
+    const r = checkProfileRegistration(request(p, { deviceId: "dev-other", capabilityType: "cnc-milling", claimedDigest: "0x" + "0".repeat(64) }));
+    expect(codes(r)).toEqual(["device-mismatch", "capability-type-mismatch", "unverifiable-term", "digest-mismatch"]);
+  });
+});
+
+describe("profile registration — checks, digest and stored row are one copy (astra pack 39 discipline)", () => {
+  it("the profile returned for storage is a copy, not the caller's object, and later mutation cannot reach it", () => {
+    const p = cameraProfile();
+    const r = checkProfileRegistration(request(p));
+    expect(r.ok).toBe(true);
+    if (!r.ok) return;
+    expect(r.profile).not.toBe(p);
+    p.device.deviceId = "dev-mutated-after-check";
+    expect(r.profile.device.deviceId).toBe(CAMERA);
+    expect(r.profileDigest).toBe(computeMeasurementProfileDigest(cameraProfile()));
+  });
+
+  // A getter could answer the check and the stored row differently, so the
+  // plain-data boundary refuses it without reading it (astra pack 154; it was
+  // once read exactly once, which still ran code supplied with the data).
+  it("a getter that could lie after the first read is refused, never read", () => {
+    const p = cameraProfile();
+    let reads = 0;
+    Object.defineProperty(p.device, "deviceId", {
+      enumerable: true,
+      configurable: true,
+      get: () => (reads++ === 0 ? CAMERA : "dev-other"),
+    });
+    const r = checkProfileRegistration(request(p));
+    expect(codes(r)).toEqual(["profile-invalid"]);
+    expect(reads).toBe(0);
+  });
+
+  it("a request JSON cannot carry is refused as profile-invalid, never coerced", () => {
+    const p = cameraProfile() as unknown as Record<string, unknown>;
+    (p.measurement as Record<string, unknown>).sampling = { minSamples: Number.NaN };
+    expect(codes(checkProfileRegistration(request(p)))).toEqual(["profile-invalid"]);
+  });
+});
diff --git a/packages/spec/src/evidence/index.ts b/packages/spec/src/evidence/index.ts
index 1d459b22b..7f8add4b9 100644
--- a/packages/spec/src/evidence/index.ts
+++ b/packages/spec/src/evidence/index.ts
@@ -44,6 +44,9 @@ export * from "./measurement-profile.js";
 // profileAdmitsBundle — does authenticated, bound evidence satisfy the committed
 // MeasurementProfile (level, device, version, window, samples, simulation)?
 export * from "./profile-admission.js";
+// checkProfileRegistration — may a MeasurementProfile be registered for a
+// (capability, device)? Run by the gateway registration route.
+export * from "./profile-registration.js";
 // Principal ids for FinalMilestonePackageV2: operator = CAIP-10 (D1 signer),
 // device = ed25519:0x<key> (D2 signer, registry-held, never a compromised key).
 export * from "./principal-id.js";
diff --git a/packages/spec/src/evidence/profile-registration.ts b/packages/spec/src/evidence/profile-registration.ts
new file mode 100644
index 000000000..801557aab
--- /dev/null
+++ b/packages/spec/src/evidence/profile-registration.ts
@@ -0,0 +1,113 @@
+/**
+ * checkProfileRegistration — may this MeasurementProfile be registered for a
+ * (capability, device)?
+ *
+ * pcc-gateway stores an operator's concrete profile in its own append-only
+ * table keyed by (capabilityId, deviceId) (bus #2621). The accepted-plan
+ * compiler later takes the CURRENT row's digest from the server-re-read
+ * provider snapshot (composition, bus #2238). This check is what the
+ * registration route runs before inserting a row. The route owns
+ * authentication, the kernel-ownership predicate and storage; this owns what
+ * makes a profile registrable:
+ *
+ *   - `profile-invalid`: it fails `validateMeasurementProfile`;
+ *   - `device-mismatch`: it names a different device from the row it would be
+ *     stored under, so evidence from the registered device could never qualify;
+ *   - `capability-type-mismatch`: its outcome is for another capability type;
+ *   - `unverifiable-term`: admission cannot evaluate one of its terms, so every
+ *     job under it would fail closed. Refused here rather than discovered at
+ *     settlement;
+ *   - `digest-mismatch`: the client sent a digest that is not the digest of
+ *     the profile it sent.
+ *
+ * Every check runs on one plain-data copy of the request (`plainDataCopy`:
+ * each field read exactly once), and the profile returned for storage is that
+ * copy, so what is checked, digested and stored is one thing. The digest is
+ * always computed here, from that copy. A client-supplied digest is only ever
+ * compared, never stored or trusted.
+ * Every problem is reported, not just the first, so an operator can fix a
+ * profile in one pass.
+ */
+
+import {
+  computeMeasurementProfileDigest,
+  plainDataCopy,
+  validateMeasurementProfile,
+  type MeasurementProfileDigest,
+  type MeasurementProfileV1,
+} from "./measurement-profile.js";
+import { unverifiableProfileTerms } from "./profile-admission.js";
+
+export type ProfileRegistrationCode =
+  | "profile-invalid"
+  | "device-mismatch"
+  | "capability-type-mismatch"
+  | "unverifiable-term"
+  | "digest-mismatch";
+
+export interface ProfileRegistrationProblem {
+  code: ProfileRegistrationCode;
+  detail: string;
+}
+
+export interface ProfileRegistrationRequest {
+  /** The type of the capability the row belongs to (from the capability record, not the request). */
+  capabilityType: string;
+  /** The device the row is keyed by. */
+  deviceId: string;
+  /** The profile as submitted, unvalidated. */
+  profile: unknown;
+  /** A digest the client computed, if it sent one. Compared, never trusted. */
+  claimedDigest?: string;
+}
+
+export type ProfileRegistrationResult =
+  | { ok: true; profile: MeasurementProfileV1; profileDigest: MeasurementProfileDigest }
+  | { ok: false; problems: ProfileRegistrationProblem[] };
+
+/** Never throws. */
+export function checkProfileRegistration(input: ProfileRegistrationRequest): ProfileRegistrationResult {
+  const copy = plainDataCopy(input);
+  if (!copy.ok || typeof copy.value !== "object" || copy.value === null) {
+    return {
+      ok: false,
+      problems: [{ code: "profile-invalid", detail: `<root>: the request is not plain JSON data (${copy.ok ? "not an object" : copy.reason})` }],
+    };
+  }
+  const request = copy.value as ProfileRegistrationRequest;
+  const violations = validateMeasurementProfile(request.profile);
+  if (violations.length > 0) {
+    return {
+      ok: false,
+      problems: violations.map((v) => ({ code: "profile-invalid" as const, detail: `${v.path || "<root>"}: ${v.message}` })),
+    };
+  }
+  const profile = request.profile as MeasurementProfileV1;
+  const problems: ProfileRegistrationProblem[] = [];
+
+  if (profile.device.deviceId !== request.deviceId) {
+    problems.push({
+      code: "device-mismatch",
+      detail: `the profile names device ${JSON.stringify(profile.device.deviceId)} but would be registered for ${JSON.stringify(request.deviceId)}`,
+    });
+  }
+  if (profile.outcome.capabilityType !== request.capabilityType) {
+    problems.push({
+      code: "capability-type-mismatch",
+      detail: `the profile is for ${JSON.stringify(profile.outcome.capabilityType)} but the capability is ${JSON.stringify(request.capabilityType)}`,
+    });
+  }
+  for (const term of unverifiableProfileTerms(profile)) {
+    problems.push({ code: "unverifiable-term", detail: term });
+  }
+
+  const profileDigest = computeMeasurementProfileDigest(profile);
+  if (request.claimedDigest !== undefined && request.claimedDigest !== profileDigest) {
+    problems.push({
+      code: "digest-mismatch",
+      detail: `the client sent ${JSON.stringify(request.claimedDigest)}; the submitted profile digests to ${profileDigest}`,
+    });
+  }
+
+  return problems.length > 0 ? { ok: false, problems } : { ok: true, profile, profileDigest };
+}