diff --git a/src/mcp/server.ts b/src/mcp/server.ts
index 4645910093..ac79098d01 100644
--- a/src/mcp/server.ts
+++ b/src/mcp/server.ts
@@ -125,7 +125,7 @@ import { MAX_FOCUS_MANIFEST_BYTES } from "../signals/focus-manifest";
 import { loadPublicRepoFocusManifest, loadRepoFocusManifest } from "../signals/focus-manifest-loader";
 import { buildPredictedGateVerdict } from "../rules/predicted-gate";
 import { buildIssueSlopAssessment, buildSlopAssessment } from "../signals/slop";
-import { buildBoundaryTestGenerationFinding, buildBoundaryTestGenerationSpec, detectBoundaryTouches } from "../signals/boundary-test-generation";
+import { buildBoundaryTestGenerationFinding, buildBoundaryTestGenerationSpec } from "../signals/boundary-test-generation";
 import { buildRepoDataQuality } from "../signals/data-quality";
 import { PREFLIGHT_LIMITS } from "../signals/preflight-limits";
 import { SCENARIO_MAX_BRANCH_REF_CHARS, SCENARIO_MAX_LINKED_ISSUE_NUMBERS, SCENARIO_MAX_REPO_FULL_NAME_CHARS } from "../scenarios/input-model";
@@ -791,13 +791,22 @@ const checkIssueSlopShape = {
 const checkIssueSlopOutputSchema = checkSlopRiskOutputSchema;
 
 // Boundary-safe test-generation suggestion (#1972): pure local-metadata, like checkSlopRisk — the agent
-// supplies changed-file paths + patch text (never full file content) plus any test evidence it already has.
-// Advisory-only; this tool never blocks or writes anything — it only returns criteria/hints for the caller's
-// OWN agent to scaffold tests from (mirrors the local-write-tools.ts no-cloud-write boundary).
+// supplies changed-file paths plus precomputed boundary-touch metadata from its local diff scan. The remote MCP
+// boundary never accepts patch/source text. Advisory-only; this tool never blocks or writes anything — it only
+// returns criteria/hints for the caller's OWN agent to scaffold tests from.
 const suggestBoundaryTestsShape = {
-  changedFiles: z
-    .array(z.object({ path: z.string().min(1).max(400), patch: z.string().max(20000).optional() }))
-    .max(500),
+  changedFiles: z.array(z.object({ path: z.string().min(1).max(400) }).strict()).max(500),
+  boundaryTouches: z
+    .array(
+      z
+        .object({
+          path: z.string().min(1).max(400),
+          kind: z.enum(["array_index_bounds", "null_or_undefined_branch", "empty_collection_check"]),
+        })
+        .strict(),
+    )
+    .max(20)
+    .optional(),
   tests: z.array(z.string().max(400)).max(2000).optional(),
   testFiles: z.array(z.string().max(400)).max(2000).optional(),
 };
@@ -1277,7 +1286,7 @@ export class GittensoryMcp {
       "gittensory_suggest_boundary_tests",
       {
         description:
-          "Boundary-safe test-generation suggestion (#1972): scan changed-file patches for a small, precise set of boundary-condition patterns (off-by-one array/index bounds, null/undefined branches, empty-collection checks) with no test evidence in the diff, and return a LOCAL-execution action spec (criteria/hints only — never generated test code) for your OWN agent to scaffold tests with. Advisory-only; never blocks, never writes.",
+          "Boundary-safe test-generation suggestion (#1972): evaluate locally precomputed boundary-touch metadata (path + pattern kind only; no patch/source text) with no test evidence in the diff, and return a LOCAL-execution action spec (criteria/hints only — never generated test code) for your OWN agent to scaffold tests with. Advisory-only; never blocks, never writes.",
         inputSchema: suggestBoundaryTestsShape,
         outputSchema: suggestBoundaryTestsOutputSchema,
       },
@@ -2294,8 +2303,9 @@ export class GittensoryMcp {
   }
 
   private suggestBoundaryTests(input: z.infer<z.ZodObject<typeof suggestBoundaryTestsShape>>): ToolPayload {
-    const touches = detectBoundaryTouches(input.changedFiles);
-    const finding = buildBoundaryTestGenerationFinding({ files: input.changedFiles, tests: input.tests, testFiles: input.testFiles });
+    const changedPaths = new Set(input.changedFiles.map((file) => file.path));
+    const touches = (input.boundaryTouches ?? []).filter((touch) => changedPaths.has(touch.path));
+    const finding = buildBoundaryTestGenerationFinding({ touches, tests: input.tests, testFiles: input.testFiles });
     const spec = finding ? buildBoundaryTestGenerationSpec(touches) : null;
     return {
       summary: finding ? "Boundary-condition code changed without test evidence." : "No boundary-condition gap detected.",
diff --git a/src/signals/boundary-test-generation.ts b/src/signals/boundary-test-generation.ts
index 18290bddee..9958d92b35 100644
--- a/src/signals/boundary-test-generation.ts
+++ b/src/signals/boundary-test-generation.ts
@@ -26,8 +26,6 @@ export type BoundaryPatternKind = "array_index_bounds" | "null_or_undefined_bran
 export type BoundaryTouch = {
   path: string;
   kind: BoundaryPatternKind;
-  /** The matched added line, trimmed, capped for display (never the full patch). */
-  snippet: string;
 };
 
 // Kept deliberately SMALL and PRECISE (per #1972's scope note: false positives are worse than a narrow
@@ -44,7 +42,6 @@ const BOUNDARY_PATTERNS: ReadonlyArray<{ kind: BoundaryPatternKind; pattern: Reg
   { kind: "empty_collection_check", pattern: EMPTY_COLLECTION_CHECK_PATTERN },
 ];
 
-const MAX_SNIPPET_LENGTH = 160;
 const MAX_TOUCHES = 20;
 
 /** Added-line prefix in a unified diff: a single leading `+` not followed by another `+` (which would be the
@@ -71,7 +68,7 @@ export function detectBoundaryTouches(files: BoundaryPatchInput[]): BoundaryTouc
     for (const line of addedLines(patch)) {
       for (const { kind, pattern } of BOUNDARY_PATTERNS) {
         if (!pattern.test(line)) continue;
-        touches.push({ path: file.path, kind, snippet: line.slice(0, MAX_SNIPPET_LENGTH) });
+        touches.push({ path: file.path, kind });
         if (touches.length >= MAX_TOUCHES) return touches;
         break; // one match per line is enough signal; avoid double-counting the same line across patterns
       }
@@ -96,11 +93,12 @@ const PATTERN_LABELS: Record<BoundaryPatternKind, string> = {
  * or evidence-covered repo sees byte-identical behavior.
  */
 export function buildBoundaryTestGenerationFinding(input: {
-  files: BoundaryPatchInput[];
+  files?: BoundaryPatchInput[] | undefined;
+  touches?: BoundaryTouch[] | undefined;
   tests?: string[] | undefined;
   testFiles?: string[] | undefined;
 }): AdvisoryFinding | null {
-  const touches = detectBoundaryTouches(input.files);
+  const touches = input.touches ?? detectBoundaryTouches(input.files ?? []);
   if (touches.length === 0) return null;
   if (hasLocalTestEvidence({ tests: input.tests, testFiles: input.testFiles })) return null;
 
@@ -120,8 +118,7 @@ export function buildBoundaryTestGenerationFinding(input: {
 export type BoundaryTestGenerationSpec = {
   action: "scaffold_boundary_tests";
   description: string;
-  /** The boundary touches this spec was generated from — criteria only, no source content beyond the already-
-   *  public per-line snippet the diff itself carries. */
+  /** The boundary touches this spec was generated from — path + pattern kind only, never source text. */
   touches: BoundaryTouch[];
   /** Natural-language hints the contributor's own agent uses to scaffold tests in the repo's own framework and
    *  conventions — content supplied by gittensory, execution stays on the contributor's machine. */
diff --git a/test/unit/boundary-test-generation.test.ts b/test/unit/boundary-test-generation.test.ts
index f7d6bc3b86..eda286d219 100644
--- a/test/unit/boundary-test-generation.test.ts
+++ b/test/unit/boundary-test-generation.test.ts
@@ -83,10 +83,10 @@ describe("detectBoundaryTouches", () => {
     expect(touches.length).toBe(20);
   });
 
-  it("truncates an oversized snippet to the display cap", () => {
-    const longLine = `+if (x === null) { ${"a".repeat(300)} }`;
-    const touches = detectBoundaryTouches([{ path: "src/long.ts", patch: longLine }]);
-    expect(touches[0]?.snippet.length).toBeLessThanOrEqual(160);
+  it("returns only path and kind metadata, never matched source snippets", () => {
+    const touches = detectBoundaryTouches([{ path: "src/long.ts", patch: "+if (x === null) return secretValue;" }]);
+    expect(touches[0]).toEqual({ path: "src/long.ts", kind: "null_or_undefined_branch" });
+    expect(touches[0] as Record<string, unknown>).not.toHaveProperty("snippet");
   });
 
   it("scans multiple files and aggregates touches across them", () => {
@@ -150,6 +150,14 @@ describe("buildBoundaryTestGenerationFinding", () => {
     expect(finding?.detail).toContain("…");
   });
 
+  it("builds from precomputed source-free touches when supplied", () => {
+    const finding = buildBoundaryTestGenerationFinding({
+      touches: [{ path: "src/list.ts", kind: "array_index_bounds" }],
+    });
+    expect(finding?.detail).toContain("array/index bounds");
+    expect(finding?.detail).toContain("src/list.ts");
+  });
+
   it("handles undefined tests/testFiles (absent input) the same as an empty list", () => {
     const finding = buildBoundaryTestGenerationFinding({
       files: [{ path: "src/list.ts", patch: "+if (items.length === 0) return null;\n" }],
@@ -167,8 +175,8 @@ describe("buildBoundaryTestGenerationSpec", () => {
 
   it("builds a scaffold-tests spec with one hint per distinct pattern kind", () => {
     const spec = buildBoundaryTestGenerationSpec([
-      { path: "src/list.ts", kind: "array_index_bounds", snippet: "list[list.length - 1]" },
-      { path: "src/user.ts", kind: "null_or_undefined_branch", snippet: "user === null" },
+      { path: "src/list.ts", kind: "array_index_bounds" },
+      { path: "src/user.ts", kind: "null_or_undefined_branch" },
     ]);
     expect(spec).not.toBeNull();
     expect(spec?.action).toBe("scaffold_boundary_tests");
@@ -179,8 +187,8 @@ describe("buildBoundaryTestGenerationSpec", () => {
 
   it("deduplicates hints when multiple touches share the same pattern kind", () => {
     const spec = buildBoundaryTestGenerationSpec([
-      { path: "src/a.ts", kind: "empty_collection_check", snippet: "a.length === 0" },
-      { path: "src/b.ts", kind: "empty_collection_check", snippet: "b.length === 0" },
+      { path: "src/a.ts", kind: "empty_collection_check" },
+      { path: "src/b.ts", kind: "empty_collection_check" },
     ]);
     expect(spec?.hints).toHaveLength(1);
     expect(spec?.touches).toHaveLength(2);
diff --git a/test/unit/mcp-suggest-boundary-tests.test.ts b/test/unit/mcp-suggest-boundary-tests.test.ts
index de83568ccb..bcd78c423e 100644
--- a/test/unit/mcp-suggest-boundary-tests.test.ts
+++ b/test/unit/mcp-suggest-boundary-tests.test.ts
@@ -19,13 +19,15 @@ describe("MCP gittensory_suggest_boundary_tests (#1972)", () => {
     const result = await client.callTool({
       name: "gittensory_suggest_boundary_tests",
       arguments: {
-        changedFiles: [{ path: "src/list.ts", patch: "+if (items.length === 0) return null;\n" }],
+        changedFiles: [{ path: "src/list.ts" }],
+        boundaryTouches: [{ path: "src/list.ts", kind: "empty_collection_check" }],
       },
     });
     expect(result.isError).toBeFalsy();
-    const data = result.structuredContent as { finding: { code: string } | null; spec: { action: string } | null };
+    const data = result.structuredContent as { finding: { code: string } | null; spec: { action: string; touches: unknown[] } | null };
     expect(data.finding?.code).toBe("boundary_test_generation_available");
     expect(data.spec?.action).toBe("scaffold_boundary_tests");
+    expect(data.spec?.touches).toEqual([{ path: "src/list.ts", kind: "empty_collection_check" }]);
     expect(JSON.stringify(data)).not.toMatch(/wallet|hotkey|reward|payout|trust score/i);
   });
 
@@ -34,7 +36,8 @@ describe("MCP gittensory_suggest_boundary_tests (#1972)", () => {
     const result = await client.callTool({
       name: "gittensory_suggest_boundary_tests",
       arguments: {
-        changedFiles: [{ path: "src/list.ts", patch: "+if (items.length === 0) return null;\n" }],
+        changedFiles: [{ path: "src/list.ts" }],
+        boundaryTouches: [{ path: "src/list.ts", kind: "empty_collection_check" }],
         testFiles: ["test/unit/list.test.ts"],
       },
     });
@@ -49,11 +52,37 @@ describe("MCP gittensory_suggest_boundary_tests (#1972)", () => {
     const result = await client.callTool({
       name: "gittensory_suggest_boundary_tests",
       arguments: {
-        changedFiles: [{ path: "src/util.ts", patch: "+export const greeting = 'hello';\n" }],
+        changedFiles: [{ path: "src/util.ts" }],
       },
     });
     expect(result.isError).toBeFalsy();
     const data = result.structuredContent as { finding: unknown };
     expect(data.finding).toBeNull();
   });
+
+  it("rejects raw patch input at the MCP boundary", async () => {
+    const client = await connect();
+    const result = await client.callTool({
+      name: "gittensory_suggest_boundary_tests",
+      arguments: {
+        changedFiles: [{ path: "src/list.ts", patch: "+if (items.length === 0) return null;\n" }],
+      },
+    });
+    expect(result.isError).toBe(true);
+  });
+
+  it("ignores boundary touches for files not listed in changedFiles", async () => {
+    const client = await connect();
+    const result = await client.callTool({
+      name: "gittensory_suggest_boundary_tests",
+      arguments: {
+        changedFiles: [{ path: "src/list.ts" }],
+        boundaryTouches: [{ path: "src/other.ts", kind: "empty_collection_check" }],
+      },
+    });
+    expect(result.isError).toBeFalsy();
+    const data = result.structuredContent as { finding: unknown; spec: unknown };
+    expect(data.finding).toBeNull();
+    expect(data.spec).toBeNull();
+  });
 });