diff --git a/docs/ERRORS.md b/docs/ERRORS.md
new file mode 100644
index 0000000..2fc69b0
--- /dev/null
+++ b/docs/ERRORS.md
@@ -0,0 +1,42 @@
+# Error-code reference
+
+This reference lists every code declared in `src/core/errors.ts`. The `check:errors` validator
+compares the table with the `ERROR_CODES` registry and scans `src/` for
+`finding(ERROR_CODES.<code>, ...)` call sites. The code list and emission status therefore stay
+aligned with the implementation; the cause and smallest-fix descriptions remain reviewed
+documentation.
+
+`emitted` means that the current source has at least one `ERROR_CODES.<code>` call site. `defined
+but not emitted` is retained below because the code is part of the exported registry, but no
+current input path produces it. A warning can still appear in a successful receipt; it is not an
+indication that data should be changed merely to remove the warning.
+
+When a fix concerns observed responses or research provenance, use the verified source value or
+actual citation. Do not invent provenance, drop rows or items, or alter observations only to make
+an audit quieter.
+
+| Code | Emission | Source locations | Cause | Smallest input fix |
+| --- | --- | --- | --- | --- |
+| `not_object` | emitted | `src/core/parse.ts` | A parser received a primitive, `null`, or array where a JSON object was required. | Replace the value at the reported path with an object, then provide that object's required fields. |
+| `invalid_schema_version` | emitted | `src/core/parse.ts` | `schemaVersion` does not equal the schema version required by the parser. | Set `schemaVersion` to the exact version named in the finding message. |
+| `missing_field` | emitted | `src/bundle.ts`, `src/core/parse.ts`, `src/dataset/index.ts`, `src/gap-map/index.ts` | A required field or relationship is missing; dataset audits also use this code for missing indicator cells as a warning. | Add the required field or mapping. For a missing observed cell, provide the verified response or leave the audit warning rather than inventing a value. |
+| `invalid_type` | emitted | `src/core/parse.ts`, `src/dataset/index.ts`, `src/gap-map/index.ts`, `src/instrument/index.ts`, `src/measurement/index.ts`, `src/recode/index.ts`, `src/topic-card/index.ts` | A value has the wrong JSON type or an unknown field was supplied; the dataset audit also uses this code for straight-line warnings. | Use the type required by the finding or remove the unknown field. A straight-line warning has no data-edit fix; review the observations instead. |
+| `invalid_identifier` | emitted | `src/core/parse.ts`, `src/instrument/index.ts` | A construct or item code fails the code pattern, a column name fails the column-name pattern, or an item code does not use its construct prefix as a warning. | Use a valid identifier and, for the prefix warning, rename the item with the construct prefix while preserving its meaning. |
+| `invalid_enum` | emitted | `src/core/parse.ts`, `src/recode/index.ts` | An enum field contains a value outside the closed vocabulary declared by the parser. | Replace it with one of the allowed values listed in the finding message. |
+| `empty_collection` | emitted | `src/core/parse.ts`, `src/instrument/index.ts`, `src/measurement/index.ts` | A required collection is absent, not an array, or empty; measurement compilation also uses this code as a warning when structural paths are absent. | Provide at least one valid member when the collection is required. For a measurement-only warning, add only a real intended hypothesis or accept the warning. |
+| `duplicate_code` | emitted | `src/dataset/index.ts`, `src/instrument/index.ts`, `src/topic-card/index.ts` | A construct code, item code, hypothesis ID, anchor value, or respondent ID is repeated. | Correct the duplicate identifier or anchor using the real distinct value; do not duplicate or delete research records just to silence the finding. |
+| `duplicate_column` | emitted | `src/dataset/index.ts` | Two dataset column definitions have the same name. | Rename one column to a new valid name or remove the redundant definition after confirming the source mapping. |
+| `invalid_scale` | emitted | `src/dataset/index.ts`, `src/gap-map/index.ts`, `src/instrument/index.ts` | A declared scale is invalid, an observed scale hint is not made of integers, or an observed response is outside the instrument's Likert bounds. | Declare an allowed scale with `min < max`, correct a scale hint to the verified integers, or correct the response only when the source record proves it was entered incorrectly. |
+| `invalid_anchor` | emitted | `src/instrument/index.ts` | A scale anchor is not an integer or falls outside the declared scale. | Use an integer anchor within the declared `min` and `max` values. |
+| `cited_without_source` | emitted | `src/instrument/index.ts` | An item is marked `cited` without a non-empty `source.citation`. | Add the actual citation, or change the item status to `demonstration` when no citation exists. |
+| `reverse_scale_unsupported` | emitted | `src/instrument/index.ts` | A scale with anchors does not include both scale endpoints, so its reverse mapping is not supported. | Add verified anchors for both declared endpoints, or omit the optional anchors when they are not needed. |
+| `unknown_construct` | emitted | `src/recode/index.ts`, `src/topic-card/index.ts` | A topic card or recode operation refers to a construct absent from the instrument. | Reference an existing construct code or add the real construct definition to the instrument. |
+| `unknown_item` | emitted | `src/dataset/index.ts`, `src/recode/index.ts` | A dataset indicator or reverse-score operation refers to an item absent from the instrument; audits also warn when an instrument item has no mapped indicator column. | Correct the item mapping to an existing item or add the real indicator column when it exists in the source dataset. |
+| `orphan_hypothesis` | emitted | `src/topic-card/index.ts` | A hypothesis has the same source and target, or refers to a construct outside the selected instrument constructs. | Reference two distinct existing construct codes and include both in `constructCodes`. |
+| `row_count_mismatch` | emitted | `src/dataset/index.ts` | `rowCount` is not equal to the number of entries in `rows`. | Set `rowCount` to the exact current `rows.length`; do not drop or add rows as a validation shortcut. |
+| `unknown_column` | emitted | `src/dataset/index.ts`, `src/recode/index.ts` | A row contains an undeclared column, or a recode operation refers to a missing source or indicator column. | Declare the actual column and its mapping, or change the operation to an existing column. |
+| `column_exists` | emitted | `src/recode/index.ts` | A recode target already exists in the dataset or in an earlier operation. | Choose a new valid `as` column name that is not already present. |
+| `non_numeric` | emitted | `src/dataset/index.ts`, `src/recode/index.ts` | A dataset audit or numeric recode operation encountered a non-numeric indicator value. | Supply the verified numeric response or use `null` for a genuinely missing response; do not coerce arbitrary text. |
+| `empty_operations` | defined but not emitted | `src/core/errors.ts` registry only | The code is exported in the registry, but the current source has no `finding(ERROR_CODES.empty_operations, ...)` call site. Empty recode operations currently use `empty_collection`. | No current input triggers this code. Do not document it as a runtime result unless a source call site is added and this table is updated. |
+| `under_identified` | emitted | `src/measurement/index.ts` | A measurement construct has fewer items than the mode-and-kind heuristic minimum; this is a warning unless `strict` is true. | Add enough real indicators to meet the applicable minimum: reliability-only 2, PLS reflective 2 or formative 1, CB-SEM reflective 3 or formative 2. This does not prove model fit. |
+| `invalid_receipt` | emitted | `src/core/receipt.ts` | A receipt has an invalid shape, status, digest, compiler field, finding, count, or digest mismatch with its input or artifact. | Regenerate the receipt from the exact input and artifact produced together; do not hand-edit digest fields. |
diff --git a/package.json b/package.json
index 7bcffbf..46465ad 100644
--- a/package.json
+++ b/package.json
@@ -52,9 +52,10 @@
     "test:watch": "vitest",
     "check:pack": "node scripts/check-pack.mjs",
     "check:schema": "node scripts/check-schema.mjs",
+    "check:errors": "node scripts/check-errors.mjs",
     "check:secrets": "node scripts/check-secrets.mjs",
     "check:smoke": "node scripts/cli-smoke.mjs",
-    "verify": "npm run typecheck && npm run build && npm run test && npm run check:schema && npm run check:pack && npm run check:secrets && npm run check:smoke"
+    "verify": "npm run typecheck && npm run build && npm run test && npm run check:schema && npm run check:errors && npm run check:pack && npm run check:secrets && npm run check:smoke"
   },
   "devDependencies": {
     "@types/node": "^22.15.3",
diff --git a/scripts/check-errors.mjs b/scripts/check-errors.mjs
new file mode 100644
index 0000000..ea509e8
--- /dev/null
+++ b/scripts/check-errors.mjs
@@ -0,0 +1,216 @@
+#!/usr/bin/env node
+
+import { readdir, readFile, stat } from "node:fs/promises";
+import { join, relative, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import * as ts from "typescript";
+
+const root = fileURLToPath(new URL("..", import.meta.url));
+
+async function listSourceFiles(directory) {
+  const entries = await readdir(directory, { withFileTypes: true });
+  const files = [];
+  for (const entry of entries.sort((left, right) => left.name.localeCompare(right.name))) {
+    const path = join(directory, entry.name);
+    if (entry.isDirectory()) {
+      files.push(...(await listSourceFiles(path)));
+    } else if (entry.name.endsWith(".ts")) {
+      files.push(path);
+    }
+  }
+  return files;
+}
+
+function tableCells(line) {
+  const cells = line.trim().split("|");
+  if (cells.length < 3 || cells[0] !== "" || cells.at(-1) !== "") {
+    return undefined;
+  }
+  return cells.slice(1, -1).map((cell) => cell.trim());
+}
+
+export function findFindingCodes(source, fileName = "source.ts") {
+  const sourceFile = ts.createSourceFile(fileName, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.TS);
+  const codes = [];
+
+  function visit(node) {
+    if (
+      ts.isCallExpression(node) &&
+      ts.isIdentifier(node.expression) &&
+      node.expression.text === "finding"
+    ) {
+      const firstArgument = node.arguments[0];
+      if (
+        firstArgument &&
+        ts.isPropertyAccessExpression(firstArgument) &&
+        ts.isIdentifier(firstArgument.expression) &&
+        firstArgument.expression.text === "ERROR_CODES" &&
+        ts.isIdentifier(firstArgument.name)
+      ) {
+        codes.push(firstArgument.name.text);
+      }
+    }
+    ts.forEachChild(node, visit);
+  }
+
+  visit(sourceFile);
+  return codes;
+}
+
+export function extractSourceLocationPaths(sourceCell) {
+  return [...sourceCell.matchAll(/`(src\/[^`]+)`/g)].map(([, path]) => path);
+}
+
+async function isValidSourceLocation(projectRoot, sourcePath) {
+  if (!sourcePath.startsWith("src/") || sourcePath.includes("..") || !sourcePath.endsWith(".ts")) {
+    return false;
+  }
+  const absolutePath = join(projectRoot, sourcePath);
+  if (relative(projectRoot, absolutePath) !== sourcePath) {
+    return false;
+  }
+  try {
+    return (await stat(absolutePath)).isFile();
+  } catch {
+    return false;
+  }
+}
+
+export async function checkErrorReference(projectRoot = root) {
+  const sourceRoot = join(projectRoot, "src");
+  const registryPath = join(sourceRoot, "core", "errors.ts");
+  const documentationPath = join(projectRoot, "docs", "ERRORS.md");
+  const errors = [];
+
+  const registrySource = await readFile(registryPath, "utf8");
+  const registryMatch = registrySource.match(/export const ERROR_CODES = \{([\s\S]*?)\} as const;/);
+  if (!registryMatch) {
+    errors.push(`Could not find the ERROR_CODES registry in ${relative(projectRoot, registryPath)}.`);
+    return { errors, registrySize: 0, emittedCount: 0 };
+  }
+
+  const registryEntries = [...registryMatch[1].matchAll(/^\s{2}([A-Za-z_][A-Za-z0-9_]*):\s*"([^"]+)",?\s*$/gm)].map(
+    ([, key, value]) => ({ key, value }),
+  );
+  const registryByCode = new Map();
+  for (const entry of registryEntries) {
+    if (registryByCode.has(entry.value)) {
+      errors.push(`Duplicate ERROR_CODES value '${entry.value}'.`);
+    }
+    registryByCode.set(entry.value, entry);
+  }
+  if (registryEntries.length === 0) {
+    errors.push("ERROR_CODES registry contains no parseable entries.");
+  }
+
+  const usageByCode = new Map([...registryByCode.keys()].map((code) => [code, new Set()]));
+  for (const path of await listSourceFiles(sourceRoot)) {
+    const source = await readFile(path, "utf8");
+    for (const key of findFindingCodes(source, path)) {
+      const entry = registryEntries.find((candidate) => candidate.key === key);
+      if (!entry) {
+        errors.push(`Source emits ERROR_CODES.${key}, but it is absent from the registry.`);
+        continue;
+      }
+      usageByCode.get(entry.value).add(relative(projectRoot, path));
+    }
+  }
+
+  const documentation = await readFile(documentationPath, "utf8");
+  const lines = documentation.split(/\r?\n/);
+  const header = "| Code | Emission | Source locations | Cause | Smallest input fix |";
+  const headerIndex = lines.indexOf(header);
+  if (headerIndex === -1 || lines[headerIndex + 1] !== "| --- | --- | --- | --- | --- |") {
+    errors.push("docs/ERRORS.md must contain the expected five-column error table.");
+  }
+
+  const rows = [];
+  if (headerIndex !== -1) {
+    for (const line of lines.slice(headerIndex + 2)) {
+      if (!line.startsWith("|")) {
+        if (rows.length > 0) {
+          break;
+        }
+        continue;
+      }
+      const cells = tableCells(line);
+      if (!cells || cells.length !== 5) {
+        errors.push(`Malformed error table row: ${line}`);
+        continue;
+      }
+      rows.push({
+        code: cells[0].replaceAll("`", ""),
+        emission: cells[1],
+        source: cells[2],
+        cause: cells[3],
+        fix: cells[4],
+      });
+    }
+  }
+
+  const rowsByCode = new Map();
+  for (const row of rows) {
+    if (rowsByCode.has(row.code)) {
+      errors.push(`docs/ERRORS.md lists '${row.code}' more than once.`);
+    }
+    rowsByCode.set(row.code, row);
+    if (!row.source || !row.cause || !row.fix) {
+      errors.push(`docs/ERRORS.md row '${row.code}' must include source, cause, and smallest input fix.`);
+    }
+    const sourcePaths = extractSourceLocationPaths(row.source);
+    if (sourcePaths.length === 0) {
+      errors.push(`docs/ERRORS.md row '${row.code}' must include at least one backticked src/*.ts source location.`);
+    }
+    for (const sourcePath of sourcePaths) {
+      if (!(await isValidSourceLocation(projectRoot, sourcePath))) {
+        errors.push(`docs/ERRORS.md row '${row.code}' references missing or invalid source path '${sourcePath}'.`);
+      }
+    }
+  }
+
+  for (const code of registryByCode.keys()) {
+    const row = rowsByCode.get(code);
+    if (!row) {
+      errors.push(`docs/ERRORS.md is missing registry code '${code}'.`);
+      continue;
+    }
+    const expectedEmission = usageByCode.get(code).size > 0 ? "emitted" : "defined but not emitted";
+    if (row.emission !== expectedEmission) {
+      errors.push(`Code '${code}' is marked '${row.emission}', expected '${expectedEmission}'.`);
+    }
+    if (expectedEmission === "emitted") {
+      const documentedPaths = new Set(extractSourceLocationPaths(row.source));
+      for (const path of usageByCode.get(code)) {
+        if (!documentedPaths.has(path)) {
+          errors.push(`Code '${code}' is emitted from '${path}', but docs/ERRORS.md does not list that source location.`);
+        }
+      }
+      for (const path of documentedPaths) {
+        if (!usageByCode.get(code).has(path)) {
+          errors.push(`Code '${code}' lists '${path}', but no semantic finding(ERROR_CODES.<code>, ...) call site exists there.`);
+        }
+      }
+    }
+  }
+
+  for (const code of rowsByCode.keys()) {
+    if (!registryByCode.has(code)) {
+      errors.push(`docs/ERRORS.md lists '${code}', but it is absent from the ERROR_CODES registry.`);
+    }
+  }
+
+  return {
+    errors,
+    registrySize: registryByCode.size,
+    emittedCount: [...usageByCode.values()].filter((paths) => paths.size > 0).length,
+  };
+}
+
+if (process.argv[1] && resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
+  const result = await checkErrorReference();
+  if (result.errors.length > 0) {
+    process.stderr.write(`Error reference check failed:\n${result.errors.map((message) => `- ${message}`).join("\n")}\n`);
+    process.exit(1);
+  }
+  process.stdout.write(`error reference: pass (${result.registrySize} registry entries, ${result.emittedCount} emitted)\n`);
+}
diff --git a/test/check-errors.test.ts b/test/check-errors.test.ts
new file mode 100644
index 0000000..cbc9567
--- /dev/null
+++ b/test/check-errors.test.ts
@@ -0,0 +1,29 @@
+import { describe, expect, it } from "vitest";
+import { extractSourceLocationPaths, findFindingCodes } from "../scripts/check-errors.mjs";
+
+describe("error reference call-site detection", () => {
+  it("only counts the first argument of a semantic finding call", () => {
+    const source = `
+      const unrelated = ERROR_CODES.invalid_type;
+      const documentation = "finding(ERROR_CODES.missing_field, path, message)";
+      // finding(ERROR_CODES.unknown_column, path, message)
+      /* finding(ERROR_CODES.non_numeric, path, message) */
+      const object = { finding: () => undefined };
+      object.finding(ERROR_CODES.invalid_enum, path, message);
+      finding(
+        ERROR_CODES.invalid_receipt,
+        path,
+        message,
+      );
+    `;
+
+    expect(findFindingCodes(source)).toEqual(["invalid_receipt"]);
+  });
+
+  it("supports documented source paths without accepting arbitrary path text", () => {
+    expect(extractSourceLocationPaths("`src/core/errors.ts`, `src/dataset/index.ts`"))
+      .toEqual(["src/core/errors.ts", "src/dataset/index.ts"]);
+    expect(extractSourceLocationPaths("registry only; no source path"))
+      .toEqual([]);
+  });
+});