fix(evidence): authenticate a single record before classifying it as not-bundle

The schema-only check admitted a record whose evidence_id no longer
matches its content, so a tampered record was reported as a caller
selection error instead of an integrity mismatch. Use the authenticating
Evidence parser; only an authentic record is a mis-selected file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/application/EvidenceBundleFiles.ts

@@ -1,8 +1,11 @@
+import { resolve } from "node:path";
+
 import {
   createImmutableEvidenceBundle,
   describeEvidenceBundleFailure,
   describeValidationFailure,
   parseEvidenceBundle,
+  singleEvidenceRecordId,
   type EvidenceBundle,
 } from "../domain/evidenceBundle.js";
 import {
@@ -79,6 +82,16 @@ const readBundle = async (
   try {
     bundle = parseBundle(loaded.value);
   } catch (cause: unknown) {
+    // An intact record is the wrong selected file, not damaged bundle content.
+    const evidenceId = singleEvidenceRecordId(loaded.value);
+    if (evidenceId !== undefined)
+      return err(
+        new EvidenceFileError("read", "not-bundle", {
+          cause,
+          path: resolve(path),
+          evidenceId,
+        }),
+      );
     return err(
       new EvidenceIntegrityError("Evidence bundle validation failed", {
         cause,

src/domain/analysisErrorPresentation.ts

@@ -26,6 +26,7 @@ import {
 } from "./hopperErrors.js";
 import { ProviderSelectionError } from "./providerSelectionError.js";
 import { UnknownRegistryError } from "./unknownRegistryError.js";
+import { singleEvidenceRecordMessage } from "./evidenceBundle.js";
 import { providerRetryAction } from "./providerOperationHealth.js";
 import type { AnalysisError, AnalysisErrorTag } from "./analysisErrorBase.js";
 import type { AnalysisErrorProjection } from "./analysisErrorProjection.js";
@@ -148,6 +149,7 @@ export const analysisErrorCategory = (
     error instanceof EvidenceFileError &&
     (error.reason === "missing" ||
       error.reason === "not-file" ||
+      error.reason === "not-bundle" ||
       error.reason === "exists")
   )
     return "invalid_input";
@@ -406,6 +408,7 @@ const evidenceFileMessage = ({
   operation,
   reason,
   published,
+  evidenceId,
 }: EvidenceFileError): string => {
   if (published !== undefined)
     return "The output file was published, but staging cleanup remains incomplete.";
@@ -415,6 +418,7 @@ const evidenceFileMessage = ({
       : "Evidence output directory does not exist. Choose an existing directory and try again.";
   if (reason === "not-file")
     return "Evidence path does not point to a regular file. Choose a file and try again.";
+  if (reason === "not-bundle") return singleEvidenceRecordMessage(evidenceId);
   if (reason === "exists")
     return "Evidence file already exists. Choose another path or allow overwrite.";
   if (reason === "invalid-json")

src/domain/analysisErrorProjection.ts

@@ -311,6 +311,9 @@ const artifactStateErrorDetails = (
       operation: error.operation,
       reason: error.reason,
       ...(error.path === undefined ? {} : { path: error.path }),
+      ...(error.evidenceId === undefined
+        ? {}
+        : { evidence_id: error.evidenceId }),
       ...(error.published === undefined
         ? {}
         : {

src/domain/evidenceBundle.ts

@@ -212,14 +212,32 @@ export const describeEvidenceBundleFailure = (
   input: unknown,
   cause: unknown,
 ): string => {
-  const record = evidenceSchema.safeParse(input);
+  const recordId = singleEvidenceRecordId(input);
-  if (record.success)
+  if (recordId !== undefined) return singleEvidenceRecordMessage(recordId);
-    return `Expected an Evidence bundle with records and manifest arrays, but this JSON is one Evidence record (${record.data.evidence_id}). Export a session bundle with the MCP export_evidence_bundle tool and supply that file.`;
   return cause instanceof z.ZodError
     ? `Evidence bundle does not match the bundle schema ${describeValidationFailure(cause)}. Supply an unmodified bundle written by export_evidence_bundle or rea evidence-export.`
     : `Evidence bundle validation failed: ${describeValidationFailure(cause)}. Recreate or re-export the bundle, then try again.`;
 };
 
+/**
+ * Identify an authentic single Evidence record supplied where a bundle is
+ * expected. A record whose semantic identifier does not match its content is
+ * damaged, not a mis-selected file, so it remains an integrity failure.
+ */
+export const singleEvidenceRecordId = (input: unknown): string | undefined => {
+  try {
+    return parseEvidence(input).evidence_id;
+  } catch {
+    return undefined;
+  }
+};
+
+/** Explain how to obtain a bundle when one Evidence record was supplied. */
+export const singleEvidenceRecordMessage = (
+  evidenceId: string | undefined,
+): string =>
+  `Expected an Evidence bundle with records and manifest arrays, but this JSON is one Evidence record${evidenceId === undefined ? "" : ` (${evidenceId})`}. Export a session bundle with the MCP export_evidence_bundle tool and supply that file.`;
+
 /** Locate the first schema issue, or keep a thrown constraint message. */
 export const describeValidationFailure = (cause: unknown): string => {
   if (!(cause instanceof z.ZodError))

src/domain/evidenceErrors.ts

@@ -50,17 +50,27 @@ export class EvidenceFileError extends AnalysisError {
   readonly path: string | undefined;
   /** Present only when a write committed before cleanup failed. */
   readonly published: PublishedEvidenceFile | undefined;
+  /** The single Evidence record found where a bundle was expected. */
+  readonly evidenceId: string | undefined;
 
   constructor(
     readonly operation: "read" | "write",
-    readonly reason: "not-file" | "exists" | "invalid-json" | "missing" | "io",
+    readonly reason:
+      | "not-file"
+      | "not-bundle"
+      | "exists"
+      | "invalid-json"
+      | "missing"
+      | "io",
     options?: AnalysisErrorOptions & {
       readonly path?: string;
       readonly published?: PublishedEvidenceFile;
+      readonly evidenceId?: string;
     },
   ) {
     super(`Evidence bundle ${operation} failed: ${reason}`, options);
     this.path = options?.path;
     this.published = options?.published;
+    this.evidenceId = options?.evidenceId;
   }
 }

tests/boundary/filesystem/evidenceBundleFiles.test.ts

@@ -439,13 +439,15 @@ describe("evidence bundle filesystem adapter", () => {
     const record = bundle().records[0];
     const single = join(directory, "record.json");
     await writeFile(single, JSON.stringify(record));
+    // An intact record is the caller's file selection, not damaged content.
     expect(await readEvidenceBundle(single)).toMatchObject({
       ok: false,
       error: {
-        _tag: "EvidenceIntegrityError",
+        _tag: "EvidenceFileError",
-        userMessage: expect.stringContaining(
+        operation: "read",
-          `this JSON is one Evidence record (${String(record?.evidence_id)})`,
+        reason: "not-bundle",
-        ),
+        path: single,
+        evidenceId: record?.evidence_id,
       },
     });
 
@@ -477,3 +479,21 @@ describe("evidence bundle filesystem adapter", () => {
     });
   });
 });
+
+describe("evidence bundle single-record selection", () => {
+  it("keeps a tampered single record an integrity failure", async () => {
+    const directory = await createTestTempDirectory("rea-evidence-");
+    const record = bundle().records[0];
+    // A record whose identifier no longer matches its content is damaged,
+    // not a mis-selected file.
+    const tampered = join(directory, "tampered-record.json");
+    await writeFile(
+      tampered,
+      JSON.stringify({ ...record, operation: "tampered_operation" }),
+    );
+    expect(await readEvidenceBundle(tampered)).toMatchObject({
+      ok: false,
+      error: { _tag: "EvidenceIntegrityError" },
+    });
+  });
+});

tests/boundary/mcp/bundleComparisonMcp.test.ts

@@ -134,10 +134,17 @@ describe("bundle comparison MCP integration", () => {
       expect(result.isError).toBe(true);
       expect(parseMcpToolError(result)).toMatchObject({
         error: {
-          code: "evidence_integrity_mismatch",
+          code: "invalid_request",
+          category: "invalid_input",
           message: expect.stringContaining(
             `this JSON is one Evidence record (${record.evidence_id})`,
           ),
+          details: {
+            operation: "read",
+            reason: "not-bundle",
+            path: recordPath,
+            evidence_id: record.evidence_id,
+          },
         },
       });
     } finally {