diff --git a/packages/cli/tests/case-sudo-fixture.mjs b/packages/cli/tests/case-sudo-fixture.mjs
index 866c6c0d2..445bb4fa9 100644
--- a/packages/cli/tests/case-sudo-fixture.mjs
+++ b/packages/cli/tests/case-sudo-fixture.mjs
@@ -100,9 +100,15 @@ function sessionPairs(pairs) {
 // Safety net for a removed-outer-bound change. It is fixture cleanup, never
 // product supervision. The guard reads only fixture records and checks sid
 // immediately before every kill. Normal outer-bound cases return before it.
-export function fixtureGuard(t,files,milliseconds=9500) {
-  const program=`const fs=require('node:fs');setTimeout(()=>{for(const file of JSON.parse(process.argv[1])){let rows=[];try{rows=fs.readFileSync(file,'utf8').trim().split(String.fromCharCode(10))}catch{}for(const row of rows){const [pid,sid]=row.trim().split(' ').map(Number);if(!(pid>0&&sid>0))continue;try{const raw=fs.readFileSync('/proc/'+pid+'/stat','utf8'),f=raw.slice(raw.lastIndexOf(') ')+2).split(' ');if(Number(f[3])===sid&&f[0]!=='Z')process.kill(pid,'SIGKILL')}catch{}}}},Number(process.argv[2]));`;
-  const child=spawn(process.execPath,['-e',program,JSON.stringify(files),String(milliseconds)],{stdio:'ignore'});
+export function fixtureGuard(t,files,milliseconds=9500,startFile) {
+  // P10 already records the instant its observed probe starts. Arm its safety
+  // net there, so unrelated host-fixture setup cannot consume the probe budget.
+  // Callers without an observer retain the original immediate-start behavior.
+  const program=`const fs=require('node:fs');
+function cleanup(){for(const file of JSON.parse(process.argv[1])){let rows=[];try{rows=fs.readFileSync(file,'utf8').trim().split(String.fromCharCode(10))}catch{}for(const row of rows){const [pid,sid]=row.trim().split(' ').map(Number);if(!(pid>0&&sid>0))continue;try{const raw=fs.readFileSync('/proc/'+pid+'/stat','utf8'),f=raw.slice(raw.lastIndexOf(') ')+2).split(' ');if(Number(f[3])===sid&&f[0]!=='Z')process.kill(pid,'SIGKILL')}catch{}}}}
+function arm(){setTimeout(cleanup,Number(process.argv[2]));}
+if(!process.argv[3])arm();else{const poll=setInterval(()=>{let text='';try{text=fs.readFileSync(process.argv[3],'utf8')}catch{}if(/^begin [0-9]+[.][0-9]{2}\\n/.test(text)){clearInterval(poll);arm();}},10);}`;
+  const child=spawn(process.execPath,['-e',program,JSON.stringify(files),String(milliseconds),...(startFile?[startFile]:[])],{stdio:'ignore'});
   const stop=async()=>{
     if(child.exitCode!==null||child.signalCode!==null)return;
     const exited=new Promise(resolve=>child.once('exit',resolve));
diff --git a/packages/cli/tests/case-sudo-fixture.test.mjs b/packages/cli/tests/case-sudo-fixture.test.mjs
new file mode 100644
index 000000000..52a499079
--- /dev/null
+++ b/packages/cli/tests/case-sudo-fixture.test.mjs
@@ -0,0 +1,33 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { spawn } from 'node:child_process';
+import { once } from 'node:events';
+import { mkdtempSync, readFileSync, writeFileSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { fixtureGuard } from './case-sudo-fixture.mjs';
+
+test('fixture cleanup guard starts its budget at the probe marker', async t => {
+  const dir = mkdtempSync(join(tmpdir(), 'guard-'));
+  t.after(() => rmSync(dir, { recursive: true, force: true }));
+  const records = join(dir, 'pids'), startFile = join(dir, 'probe');
+  writeFileSync(startFile, '');
+  const child = spawn(process.execPath, ['-e', 'setInterval(()=>{},1000)'], { stdio: 'ignore' });
+  const exited = once(child, 'exit');
+  t.after(() => { if (child.exitCode === null && child.signalCode === null) child.kill('SIGKILL'); });
+  const raw = readFileSync(`/proc/${child.pid}/stat`, 'utf8');
+  const sid = Number(raw.slice(raw.lastIndexOf(') ') + 2).split(' ')[3]);
+  writeFileSync(records, `${child.pid} ${sid}\n`);
+  const stop = fixtureGuard(t, [records], 100, startFile);
+  // An empty marker is setup, not the start of the observed probe. This wait
+  // exceeds the cleanup budget deliberately; no production bound is changed.
+  await new Promise(resolve => setTimeout(resolve, 500));
+  assert.equal(child.signalCode, null, 'setup must not consume the probe cleanup budget');
+  writeFileSync(startFile, 'begin 100.00\n');
+  const terminal = await Promise.race([exited, new Promise((_, reject) => {
+    const timer = setTimeout(() => reject(new Error('armed fixture guard did not clean up')), 3000);
+    timer.unref();
+  })]);
+  assert.deepEqual(terminal, [null, 'SIGKILL']);
+  await stop();
+});
diff --git a/packages/cli/tests/case1-accept.test.mjs b/packages/cli/tests/case1-accept.test.mjs
index cc1b582fe..5f0c9592a 100644
--- a/packages/cli/tests/case1-accept.test.mjs
+++ b/packages/cli/tests/case1-accept.test.mjs
@@ -429,7 +429,7 @@ for(const fault of ['inner','outer','overflow'])test(`row253 C4 P10 ${fault} rea
    assert.equal(baseline.status,0,baseline.out+baseline.err);
    assert.deepEqual(await pollFixtureGone(files),[],'baseline leaves no session');
   }
-  const capture=cleanupFixture(t,files);const stop=fixtureGuard(t,files,7000);
+  const capture=cleanupFixture(t,files);
   if(fault==='inner')put(join(h.hc,'peer-hang'),'');
   if(fault==='outer'){put(join(h.hc,'stall-probe'),'');put(join(h.hc,'stall-output'),'200 997 997\n');}
   if(fault==='overflow'){put(join(h.hc,'peer-output'),'200 997 997\n'+'X'.repeat(256));put(join(h.hc,'peer-status'),'0');}
@@ -440,6 +440,7 @@ for(const fault of ['inner','outer','overflow'])test(`row253 C4 P10 ${fault} rea
    put(join(h.dir,'selector.sh'),read(join(REPO,'scripts','selector.sh')),0o644);
    assert.equal(removeP10Observers(read(observedScript)),read(SCRIPT),'observer reversal equals a fresh shipped script read');
   }
+  const stop=fixtureGuard(t,files,7000,timingFile);
   const start=performance.now(),r=run(h,timingFile?{ROW299_TIMING_FILE:timingFile}:{},undefined,observedScript),seconds=(performance.now()-start)/1000;capture();
   assert.equal(r.status,0,r.out+r.err);
   const reason=fault==='inner'?'inner-timeout':fault==='outer'?'outer-timeout':'output-limit';
diff --git a/packages/cli/tests/refusal-redaction.test.mjs b/packages/cli/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..4c1e9f87f
--- /dev/null
+++ b/packages/cli/tests/refusal-redaction.test.mjs
@@ -0,0 +1,44 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+import { spawnSync } from 'node:child_process';
+import { readFileSync } from 'node:fs';
+import { fixture } from './helpers.mjs';
+const repo = join(import.meta.dirname, '../../..');
+test('task file JSON refusal preserves exit 2 and file without parser bytes', t => {
+  const file = write(join(scratch(t), 'task.json'));
+  const r = spawnSync(process.execPath, [join(repo, 'scripts/mosaic-task.mjs'), 'validate', file], { encoding: 'utf8', env: { PATH: process.env.PATH, HOME: process.env.HOME, TMPDIR: process.env.TMPDIR } });
+  assert.equal(r.status, 2, r.stderr);
+  assert.ok(r.stderr.includes(file), r.stderr);
+  assert.match(r.stderr, /task file is not valid JSON/);
+  assert.doesNotMatch(r.stdout + r.stderr, /sk-test|Unexpected token/);
+});
+test('case2 precheck business helper omits parser bytes in its BUSINESS fact', t => {
+  const root = scratch(t), f = fixture(root);
+  const file = write(join(root, 'config/businesses/acme.json'));
+  // Execute the production facts helper, without host or credential checks.
+  const shell = readFileSync(join(repo, 'scripts/case2-precheck.sh'), 'utf8');
+  const start = shell.indexOf('facts="$(cd "$REPO" && node --input-type=module -e \'') + 'facts="$(cd "$REPO" && node --input-type=module -e \''.length;
+  assert.ok(start > 100);
+  const end = shell.indexOf("' \"$REPO\" \"$BUSINESS\"", start);
+  assert.ok(end > start);
+  const r = spawnSync(process.execPath, ['--input-type=module', '-e', shell.slice(start, end), repo, 'acme'], { encoding: 'utf8', env: { ...f.env, HOME: process.env.HOME, TMPDIR: process.env.TMPDIR, PATH: process.env.PATH } });
+  assert.equal(r.status, 0, r.stderr);
+  assert.ok(r.stdout.includes(`BUSINESS\tbad\tcannot read ${file}:`), r.stdout);
+  assert.doesNotMatch(r.stdout + r.stderr, /sk-test|Unexpected token/);
+});
diff --git a/packages/control-board/src/scan.mjs b/packages/control-board/src/scan.mjs
index e89c25e99..b50cf6390 100644
--- a/packages/control-board/src/scan.mjs
+++ b/packages/control-board/src/scan.mjs
@@ -13,6 +13,7 @@
 // exception is <boardDir>/seen.json, which holds Jason's "seen" marks and is
 // only changed when he clicks; a scan reads it and never rewrites it.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import { existsSync, readFileSync, readdirSync, statSync, mkdirSync, writeFileSync, renameSync } from "node:fs";
 import { join, basename, isAbsolute, resolve } from "node:path";
 import { homedir } from "node:os";
@@ -35,9 +36,9 @@ export function loadConfig(path = defaultConfigPath()) {
   if (!existsSync(path)) throw new ConfigError(`config not found: ${path}`);
   let raw;
   try {
-    raw = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new ConfigError(`config is not valid JSON: ${path} (${err.message})`);
+    raw = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new ConfigError(`config is not valid JSON: ${path}`);
   }
   if (!raw || typeof raw !== "object" || Array.isArray(raw)) throw new ConfigError(`config is not an object: ${path}`);
   if (typeof raw.dataRoot !== "string" || !isAbsolute(raw.dataRoot)) {
@@ -227,9 +228,9 @@ export function loadSeen(boardDir) {
   if (!existsSync(path)) return {};
   let parsed;
   try {
-    parsed = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new ConfigError(`seen marks file is not valid JSON: ${path} (${err.message})`);
+    parsed = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new ConfigError(`seen marks file is not valid JSON: ${path}`);
   }
   if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) throw new ConfigError(`seen marks file must be a JSON object: ${path}`);
   for (const [k, v] of Object.entries(parsed)) {
diff --git a/packages/control-board/tests/refusal-redaction.test.mjs b/packages/control-board/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..e7f9b50e7
--- /dev/null
+++ b/packages/control-board/tests/refusal-redaction.test.mjs
@@ -0,0 +1,34 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { ConfigError, loadConfig, loadSeen } from '../src/scan.mjs';
+for (const kind of ['config', 'seen']) test(`${kind} JSON refusal names only the file`, t => {
+  const root = scratch(t), file = write(join(root, kind === 'config' ? 'config.json' : 'seen.json'));
+  assert.throws(() => kind === 'config' ? loadConfig(file) : loadSeen(root), safe(file, ConfigError));
+});
diff --git a/packages/discord/extension/tools.mjs b/packages/discord/extension/tools.mjs
index 41e1f2b7b..774a8658b 100644
--- a/packages/discord/extension/tools.mjs
+++ b/packages/discord/extension/tools.mjs
@@ -15,6 +15,7 @@
 // The per-message budget resets on agent_start, the event pi emits once per
 // prompt run, so a follow-up message gets a fresh budget.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import { Type } from "typebox";
 import { TOOLS_ENV, TOOL_DESCRIPTIONS, READ_MAX_LINES, loadToolsConfig, createToolSet, enabledToolNames } from "../src/tools.mjs";
 import { COMMIT_MESSAGE_MAX, COMMIT_PATHS_MAX, VAULT_PREFIXES } from "../src/git.mjs";
@@ -141,9 +142,9 @@ export default function (pi) {
   if (typeof raw !== "string" || raw.length === 0) throw new Error(`${TOOLS_ENV} is not set; the connector sets it from the binding's tools key`);
   let parsed;
   try {
-    parsed = JSON.parse(raw);
-  } catch (err) {
-    throw new Error(`${TOOLS_ENV} is not valid JSON: ${err.message}`);
+    parsed = parseJsonFileText(raw, TOOLS_ENV);
+  } catch {
+    throw new Error(`${TOOLS_ENV} is not valid JSON`);
   }
   const config = loadToolsConfig(parsed);
   const tools = createToolSet(config);
diff --git a/packages/discord/src/approvals.mjs b/packages/discord/src/approvals.mjs
index cc33b1a88..516af3d65 100644
--- a/packages/discord/src/approvals.mjs
+++ b/packages/discord/src/approvals.mjs
@@ -19,6 +19,7 @@
 // Ids in this file are private to the binding's data directory (0600),
 // like every other journal.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import { appendFileSync, existsSync, readFileSync } from "node:fs";
 import { join } from "node:path";
 import { DiscordError } from "./errors.mjs";
@@ -104,9 +105,9 @@ export function readApprovals(dir) {
   for (const [i, line] of readFileSync(path, "utf8").split("\n").entries()) {
     if (line.length === 0) continue;
     try {
-      out.push(JSON.parse(line));
-    } catch (err) {
-      throw new DiscordError(`${path}:${i + 1}: not valid JSON (${err.message})`);
+      out.push(parseJsonFileText(line, `${path}:${i + 1}`));
+    } catch {
+      throw new DiscordError(`${path}:${i + 1}: not valid JSON`);
     }
   }
   return out;
diff --git a/packages/discord/src/binding.mjs b/packages/discord/src/binding.mjs
index 7dac0f56d..c620997c8 100644
--- a/packages/discord/src/binding.mjs
+++ b/packages/discord/src/binding.mjs
@@ -18,6 +18,7 @@
 // Absent means no tools and a launch exactly as before. It is a fixed
 // key: the extension reads it at pi start.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import { existsSync, lstatSync, readFileSync, realpathSync, statSync } from "node:fs";
 import { loadWebConfig } from "./web.mjs";
 import { loadSetsparkConfig } from "./setspark.mjs";
@@ -59,9 +60,9 @@ export function loadDataRoot(path = defaultConfigPath()) {
   if (!existsSync(path)) throw new DiscordError(`config not found: ${path}`);
   let raw;
   try {
-    raw = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new DiscordError(`config is not valid JSON: ${path} (${err.message})`);
+    raw = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new DiscordError(`config is not valid JSON: ${path}`);
   }
   if (!raw || typeof raw !== "object" || Array.isArray(raw)) throw new DiscordError(`config is not an object: ${path}`);
   if (typeof raw.dataRoot !== "string" || !isAbsolute(raw.dataRoot)) throw new DiscordError(`config.dataRoot must be an absolute path: ${path}`);
@@ -292,9 +293,9 @@ export function loadBinding(path) {
   checkPrivateFile(path, "binding");
   let raw;
   try {
-    raw = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new DiscordError(`binding is not valid JSON: ${path} (${err.message})`);
+    raw = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new DiscordError(`binding is not valid JSON: ${path}`);
   }
   return validateBinding(raw, `binding ${path}`);
 }
diff --git a/packages/discord/src/journal.mjs b/packages/discord/src/journal.mjs
index f5d8f3e62..61ddea826 100644
--- a/packages/discord/src/journal.mjs
+++ b/packages/discord/src/journal.mjs
@@ -20,6 +20,7 @@
 //                  supervised form for a service unit's pre-start
 // Directories are 0700, files 0600. Lines are appended, never rewritten.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import {
   appendFileSync, closeSync, constants, existsSync, fstatSync, fsyncSync, mkdirSync, openSync, readdirSync, readFileSync, readSync, renameSync, rmdirSync, rmSync,
   unlinkSync, writeFileSync, writeSync,
@@ -47,9 +48,9 @@ function readLines(path) {
   for (const [i, line] of text.split("\n").entries()) {
     if (line.length === 0) continue;
     try {
-      out.push(JSON.parse(line));
-    } catch (err) {
-      throw new DiscordError(`${path}:${i + 1}: not valid JSON (${err.message})`);
+      out.push(parseJsonFileText(line, `${path}:${i + 1}`));
+    } catch {
+      throw new DiscordError(`${path}:${i + 1}: not valid JSON`);
     }
   }
   return out;
diff --git a/packages/discord/tests/refusal-redaction.test.mjs b/packages/discord/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..8638c0f59
--- /dev/null
+++ b/packages/discord/tests/refusal-redaction.test.mjs
@@ -0,0 +1,51 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { DiscordError } from '../src/errors.mjs';
+import { loadDataRoot, loadBinding } from '../src/binding.mjs';
+import { readApprovals } from '../src/approvals.mjs';
+import { readInboxIds } from '../src/journal.mjs';
+import extension from '../extension/tools.mjs';
+import { TOOLS_ENV } from '../src/tools.mjs';
+for (const [name, read, relative] of [
+  ['config', (file) => loadDataRoot(file), 'config.json'],
+  ['binding', (file) => loadBinding(file), 'binding.json'],
+  ['approvals', (_file, root) => readApprovals(root), 'approvals.jsonl'],
+  ['journal', (_file, root) => readInboxIds(root), 'inbox.jsonl'],
+]) test(`${name} JSON refusal omits parser bytes`, t => {
+  const root = scratch(t), ledger = name === 'approvals' || name === 'journal';
+  const file = write(join(root, relative), ledger ? '{}\n' + malformed : malformed);
+  assert.throws(() => read(file, root), safe(ledger ? `${file}:2` : file, DiscordError, { exitCode: 2 }));
+});
+test('tools environment JSON refusal names the config key without its bytes', () => {
+  const previous = process.env[TOOLS_ENV];
+  process.env[TOOLS_ENV] = malformed;
+  try { assert.throws(() => extension({}), safe(TOOLS_ENV, Error)); }
+  finally { if (previous === undefined) delete process.env[TOOLS_ENV]; else process.env[TOOLS_ENV] = previous; }
+});
diff --git a/packages/harness/src/bundle.mjs b/packages/harness/src/bundle.mjs
index 9aa943c7d..f3ad798b3 100644
--- a/packages/harness/src/bundle.mjs
+++ b/packages/harness/src/bundle.mjs
@@ -36,7 +36,7 @@ export function webPlan(resolved, harness, builtinWeb) {
     throw new BundleError(`instance ${resolved.instance}: a ${resolved.definition} role fetches only through the broker, not search-source "harness-builtin"`, "web-source-not-allowed");
   }
   if (granted && source === "harness-builtin" && !builtinWeb) {
-    throw new BundleError(`instance ${resolved.instance}: search-source "harness-builtin" has no built-in web tool on ${harness}`);
+    throw new BundleError(`instance ${resolved.instance}: search-source "harness-builtin" has no built-in web tool on the configured harness`);
   }
   return { source, builtin: granted && source === "harness-builtin" };
 }
diff --git a/packages/harness/tests/bundle.test.mjs b/packages/harness/tests/bundle.test.mjs
index fc9769689..43a9831c5 100644
--- a/packages/harness/tests/bundle.test.mjs
+++ b/packages/harness/tests/bundle.test.mjs
@@ -440,7 +440,7 @@ test("search-source harness-builtin: claude-code gets WebSearch and WebFetch and
 
 test("search-source harness-builtin is refused for a granted pi role, which has no built-in web tool", (t) => {
   const r = resolvedFor(t, "coder", (d) => (d.roles.coder.vars = { harness: "pi", model: "claude-sonnet-5-5" }));
-  assert.throws(() => build(t, withSource(granted(r), "harness-builtin")), (e) => e instanceof BundleError && /no built-in web tool on pi/.test(e.message));
+  assert.throws(() => build(t, withSource(granted(r), "harness-builtin")), (e) => e instanceof BundleError && /no built-in web tool on the configured harness/.test(e.message));
   // Without the grant the source doesn't matter on pi.
   assert.ok(!build(t, withSource(r, "harness-builtin")).manifest.builtins.some((x) => /web/i.test(x)));
 });
diff --git a/packages/harness/tests/refusal-redaction.test.mjs b/packages/harness/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..5d74b2f4e
--- /dev/null
+++ b/packages/harness/tests/refusal-redaction.test.mjs
@@ -0,0 +1,19 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { BundleError, webPlan } from '../src/bundle.mjs';
+test('harness web refusal names the harness field without the configured value', () => {
+  assert.throws(() => webPlan({ instance: 'builder', definition: 'coder', webSource: 'harness-builtin', limits: { tools: ['web'] } }, secret, false), safe('harness', BundleError, { code: 'bundle-refused' }));
+});
diff --git a/packages/ledger/tests/ledger.test.mjs b/packages/ledger/tests/ledger.test.mjs
index ebd3f2b84..4dad3ff39 100644
--- a/packages/ledger/tests/ledger.test.mjs
+++ b/packages/ledger/tests/ledger.test.mjs
@@ -65,6 +65,9 @@ function fixture(t) {
   cpSync(source, path.join(root, 'packages/ledger/src'), { recursive: true });
   // The queue section imports the queue validator and the seat registry.
   for (const pkg of ['queue', 'seat']) cpSync(path.join(source, '../..', pkg, 'src'), path.join(root, 'packages', pkg, 'src'), { recursive: true });
+  mkdirSync(path.join(root, 'packages/organization/src'), { recursive: true });
+  for (const file of ['util.mjs', 'errors.mjs', 'vocabulary.mjs'])
+    cpSync(path.join(source, '../../organization/src', file), path.join(root, 'packages/organization/src', file));
   // The fake serves ISSUES for every page, or page N of the ISSUE_PAGES array
   // (an empty page past its end). API_FAIL fails every call, or only FAIL_PAGE.
   const api = put('bin/gitea-api.sh', `#!/usr/bin/env node
diff --git a/packages/ledger/tests/queue-checks.test.mjs b/packages/ledger/tests/queue-checks.test.mjs
index 86a58ae61..49b8f5378 100644
--- a/packages/ledger/tests/queue-checks.test.mjs
+++ b/packages/ledger/tests/queue-checks.test.mjs
@@ -337,6 +337,9 @@ function cliFixture(t, rows = MAP) {
   const repo = scratchRepo(t, { map: mapText(rows, { retired: [], highWater: Math.max(...rows.map(r => r.id)) }) });
   genesisCommitted(repo);
   for (const pkg of ['ledger', 'seat']) cpSync(path.join(PACKAGES, pkg, 'src'), path.join(repo.root, 'packages', pkg, 'src'), { recursive: true });
+  mkdirSync(path.join(repo.root, 'packages/organization/src'), { recursive: true });
+  for (const file of ['util.mjs', 'errors.mjs', 'vocabulary.mjs'])
+    cpSync(path.join(PACKAGES, 'organization/src', file), path.join(repo.root, 'packages/organization/src', file));
   const dataRoot = path.join(repo.base, 'data');
   const config = path.join(repo.base, 'config.json');
   writeFileSync(config, JSON.stringify({ dataRoot }));
diff --git a/packages/organization/src/access.mjs b/packages/organization/src/access.mjs
index 07be8b55e..7d6a77421 100644
--- a/packages/organization/src/access.mjs
+++ b/packages/organization/src/access.mjs
@@ -112,10 +112,10 @@ function checkScope(value, where, check) {
 
 function checkExpires(value, where) {
   if (typeof value !== "string" || !ISO_TIME.test(value) || Number.isNaN(Date.parse(value))) {
-    refuse(`${where} must be an ISO time such as 2026-12-31T00:00:00Z (got ${JSON.stringify(value)})`);
+    refuse(`${where} must be an ISO time such as 2026-12-31T00:00:00Z`);
   }
   const iso = new Date(value).toISOString();
-  if (iso.slice(0, 19) !== value.slice(0, 19)) refuse(`${where} is not a real time: ${value}`);
+  if (iso.slice(0, 19) !== value.slice(0, 19)) refuse(`${where} is not a real time`);
 }
 
 function checkGrant(grant, at, ctx, users, seenGrants) {
@@ -133,7 +133,7 @@ function checkGrant(grant, at, ctx, users, seenGrants) {
     if (typeof p !== "string" || !UUID.test(p)) refuse(`${where} must be "*" or a bus project id, a lowercase UUID (got ${JSON.stringify(p)})`);
   });
   checkScope(grant.instances, `${at}.instances`, (x, where) => {
-    if (typeof x !== "string" || !business.instances.has(x)) refuse(`${where} must be "*" or a declared instance of ${grant.business} (got ${JSON.stringify(x)})`);
+    if (typeof x !== "string" || !business.instances.has(x)) refuse(`${where} must be "*" or a declared instance of the grant's business`);
   });
   if (!LEVELS.includes(grant.level)) refuse(`${at}.level must be one of ${LEVELS.join(", ")} (got ${JSON.stringify(grant.level)})`);
   if (grant.expires !== undefined) checkExpires(grant.expires, `${at}.expires`);
diff --git a/packages/organization/src/util.mjs b/packages/organization/src/util.mjs
index e248652fa..c50867510 100644
--- a/packages/organization/src/util.mjs
+++ b/packages/organization/src/util.mjs
@@ -20,7 +20,7 @@ export function rejectUnknownKeys(object, allowed, where) {
 
 export function requireId(value, where) {
   if (typeof value !== "string" || !ID_PATTERN.test(value)) {
-    refuse(`${where} must match ${ID_PATTERN} (got ${JSON.stringify(value)})`);
+    refuse(`${where} must match ${ID_PATTERN}`);
   }
   return value;
 }
@@ -33,7 +33,7 @@ export function requireString(value, where, { max = 200 } = {}) {
 }
 
 export function requirePositiveInt(value, where) {
-  if (!Number.isSafeInteger(value) || value < 1) refuse(`${where} must be a positive integer (got ${JSON.stringify(value)})`);
+  if (!Number.isSafeInteger(value) || value < 1) refuse(`${where} must be a positive integer`);
   return value;
 }
 
@@ -52,9 +52,9 @@ export function requireDistinctList(value, where, check, { nonEmpty = false } =
 
 // Calendar date YYYY-MM-DD that exists (2026-02-30 refuses).
 export function requireDate(value, where) {
-  if (typeof value !== "string" || !/^\d{4}-\d{2}-\d{2}$/.test(value)) refuse(`${where} must be a date YYYY-MM-DD (got ${JSON.stringify(value)})`);
+  if (typeof value !== "string" || !/^\d{4}-\d{2}-\d{2}$/.test(value)) refuse(`${where} must be a date YYYY-MM-DD`);
   const d = new Date(`${value}T00:00:00Z`);
-  if (Number.isNaN(d.getTime()) || d.toISOString().slice(0, 10) !== value) refuse(`${where} is not a real date: ${value}`);
+  if (Number.isNaN(d.getTime()) || d.toISOString().slice(0, 10) !== value) refuse(`${where} is not a real date`);
   return value;
 }
 
diff --git a/packages/organization/tests/access.test.mjs b/packages/organization/tests/access.test.mjs
index e2213e10b..b6813bd47 100644
--- a/packages/organization/tests/access.test.mjs
+++ b/packages/organization/tests/access.test.mjs
@@ -161,7 +161,7 @@ test("grants: projects is [\"*\"] or distinct lowercase UUIDs", () => {
 });
 
 test("grants: instances is [\"*\"] or distinct declared instances of that business", () => {
-  refuses(() => checkAccess(mutated((d) => { d.grants[0].instances = ["coder"]; }), context()), /grants\[0\]\.instances\[0\] must be "\*" or a declared instance of creative-hub \(got "coder"\)/);
+  refuses(() => checkAccess(mutated((d) => { d.grants[0].instances = ["coder"]; }), context()), /grants\[0\]\.instances\[0\] must be "\*" or a declared instance of the grant's business/);
   refuses(() => checkAccess(mutated((d) => { d.grants[0].instances = ["*", "writer"]; }), context()), /grants\[0\]\.instances must be \["\*"\] alone/);
   refuses(() => checkAccess(mutated((d) => { d.grants[0].instances = ["writer", "writer"]; }), context()), /duplicate entry in grants\[0\]\.instances/);
   refuses(() => checkAccess(mutated((d) => { d.grants[0].instances = []; }), context()), /grants\[0\]\.instances must not be empty/);
diff --git a/packages/organization/tests/refusal-redaction.test.mjs b/packages/organization/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..0a02f4706
--- /dev/null
+++ b/packages/organization/tests/refusal-redaction.test.mjs
@@ -0,0 +1,39 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { BusinessError } from '../src/errors.mjs';
+import { requireId, requirePositiveInt, requireDate } from '../src/util.mjs';
+import { checkAccess } from '../src/access.mjs';
+for (const [field, check, value] of [
+  ['id', requireId, secret], ['revision', requirePositiveInt, secret], ['rotateBy', requireDate, secret],
+  // Arbitrary sentinel bytes cannot pass the date-shape check to reach this branch.
+  ['rotateBy', requireDate, '2026-02-30'],
+]) test(`${field} rejects ${check.name} input without its value`, () => {
+  assert.throws(() => check(value, field), error => {
+    safe(field, BusinessError, { exitCode: 2 })(error);
+    assert.ok(!error.message.includes(value), error.message);
+    return true;
+  });
+});
+function access() { return { accessVersion: 1, revision: 1, users: [{ id: 'bean', home: 'local', subjects: [{ provider: 'test', sub: 'user' }] }], grants: [{ id: 'grant', user: 'bean', business: 'acme', projects: ['*'], instances: ['coder'], level: 'viewer' }] }; }
+const context = { providers: ['test'], peers: [], businesses: { acme: { human: 'jason', instances: ['coder'] } }, ssoSubjects: [] };
+for (const [field, value] of [['expires', secret], ['expires', '2026-02-30T00:00:00Z'], ['instances', [secret]]]) test(`grant ${field} refusal omits its value ${JSON.stringify(value)}`, () => {
+  const doc = access(); doc.grants[0][field] = value;
+  assert.throws(() => checkAccess(doc, context), error => {
+    safe(`grants[0].${field}`, BusinessError, { exitCode: 2 })(error);
+    assert.ok(!error.message.includes(Array.isArray(value) ? value[0] : value), error.message);
+    return true;
+  });
+});
diff --git a/packages/project/src/index.mjs b/packages/project/src/index.mjs
index 1f2c3664d..b0eda1e9d 100644
--- a/packages/project/src/index.mjs
+++ b/packages/project/src/index.mjs
@@ -27,7 +27,7 @@ function jsonProblems(kind, text, relative, problems) {
     const value = JSON.parse(text);
     for (const problem of validateRecord(kind, value)) problems.push(`${relative}: ${problem}`);
     return value;
-  } catch (e) { problems.push(`${relative}: invalid JSON (${e.message})`); return null; }
+  } catch { problems.push(`${relative}: invalid JSON`); return null; }
 }
 async function checkLayout(context) {
   const repo = projectRepo(context), problems = [];
diff --git a/packages/project/tests/refusal-redaction.test.mjs b/packages/project/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..b56b730c9
--- /dev/null
+++ b/packages/project/tests/refusal-redaction.test.mjs
@@ -0,0 +1,28 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+import { checkProject, initProject } from '../src/index.mjs';
+test('project record JSON problems name the file without parser bytes', async t => {
+  const root = scratch(t), context = { business: { id: 'acme', human: 'jason', projects: { stack: { root: join(root, 'code') } } }, project: 'stack', dataRoot: join(root, 'data') };
+  const { repo } = await initProject(context);
+  write(join(repo, 'requirements/REQ-1.json'));
+  const result = await checkProject(context);
+  assert.equal(result.ok, false);
+  assert.ok(result.problems.some(p => p.includes('requirements/REQ-1.json: invalid JSON')), JSON.stringify(result.problems));
+  assert.doesNotMatch(JSON.stringify(result), /sk-test|Unexpected token/);
+});
diff --git a/packages/queue/src/queue.mjs b/packages/queue/src/queue.mjs
index a29626ecb..3d17d1877 100644
--- a/packages/queue/src/queue.mjs
+++ b/packages/queue/src/queue.mjs
@@ -1025,7 +1025,7 @@ export function parseMigrationMap(text) {
   const blocks = [...text.matchAll(/^```json queue-map\n([\s\S]*?)^```$/gm)];
   if (blocks.length !== 1) throw refuse("the migration map must hold exactly one ```json queue-map block");
   let map;
-  try { map = JSON.parse(blocks[0][1]); } catch (err) { throw refuse(`the migration map's queue-map block is not JSON: ${err.message}`); }
+  try { map = JSON.parse(blocks[0][1]); } catch { throw refuse(`the migration map's queue-map block is not JSON`); }
   keysExactly(map, ["rows", "retired", "highWater"], "migration map");
   if (!Array.isArray(map.rows)) throw refuse("migration map rows must be a list");
   map.rows.forEach((r) => {
@@ -1126,7 +1126,7 @@ export function loadDoc(bytes) {
     throw refuse("queue.json is not valid UTF-8");
   }
   let doc;
-  try { doc = JSON.parse(text); } catch (err) { throw refuse(`queue.json is not JSON: ${err.message}`); }
+  try { doc = JSON.parse(text); } catch { throw refuse(`queue.json is not JSON`); }
   keysExactly(doc, DOC_KEYS, "queue.json");
   if (serialize(doc) !== text) throw refuse("queue.json does not re-serialize byte for byte (a hand edit?)");
   if (doc.version !== VERSION) throw refuse(`queue.json version ${doc.version} is not ${VERSION}`);
diff --git a/packages/queue/tests/helpers.mjs b/packages/queue/tests/helpers.mjs
index 14f127b33..0611c4610 100644
--- a/packages/queue/tests/helpers.mjs
+++ b/packages/queue/tests/helpers.mjs
@@ -1,6 +1,6 @@
 // Scratch repositories for the queue tests. Every test works under
 // os.tmpdir(): a fresh repository holding a copy of packages/queue/src and
-// the two discord helpers it imports, so the code-under-root check (8.3)
+// the discord helpers and safe JSON parser they import, so the code-under-root check (8.3)
 // passes there and nothing touches this checkout's .git.
 import { spawnSync } from "node:child_process";
 import { cpSync, mkdirSync, mkdtempSync, realpathSync, rmSync, statfsSync, writeFileSync } from "node:fs";
@@ -91,6 +91,9 @@ export function scratchRepo(t, { map = mapText(), commitMap = true, name = "repo
   cpSync(PKG_SRC, join(root, "packages/queue/src"), { recursive: true });
   mkdirSync(join(root, "packages/discord/src"), { recursive: true });
   for (const f of ["journal.mjs", "errors.mjs"]) cpSync(join(DISCORD_SRC, f), join(root, "packages/discord/src", f));
+  mkdirSync(join(root, "packages/organization/src"), { recursive: true });
+  for (const f of ["util.mjs", "errors.mjs", "vocabulary.mjs"])
+    cpSync(join(DISCORD_SRC, "../../organization/src", f), join(root, "packages/organization/src", f));
   for (const s of ["darkwing", "dewey", "filbert", "rocko", "sage"]) {
     mkdirSync(join(root, "agents", s, "work"), { recursive: true });
     writeFileSync(join(root, "agents", s, ".keep"), "");
diff --git a/packages/queue/tests/refusal-redaction.test.mjs b/packages/queue/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..062532b04
--- /dev/null
+++ b/packages/queue/tests/refusal-redaction.test.mjs
@@ -0,0 +1,24 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { loadDoc, parseMigrationMap } from '../src/queue.mjs';
+import { QueueError } from '../src/errors.mjs';
+for (const [label, parse] of [
+  ['queue.json', () => loadDoc(Buffer.from(malformed))],
+  ["migration map's queue-map block", () => parseMigrationMap('```json queue-map\n' + malformed + '\n```')],
+]) test(`${label} refusal omits parser bytes`, () => {
+  assert.throws(parse, safe(label, QueueError, { code: 2 }));
+});
diff --git a/packages/runs/src/state.mjs b/packages/runs/src/state.mjs
index af5cc9272..e226e0cb8 100644
--- a/packages/runs/src/state.mjs
+++ b/packages/runs/src/state.mjs
@@ -31,8 +31,8 @@ export function readActivePointer(dataRoot) {
   let pointer;
   try {
     pointer = JSON.parse(state.text);
-  } catch (error) {
-    throw new RunsError(`release pointer is not valid JSON (${state.file}): ${error.message}`, 2);
+  } catch {
+    throw new RunsError(`release pointer is not valid JSON (${state.file})`, 2);
   }
   const invalid = (why) => new RunsError(`release pointer ${why} (${state.file})`, 2);
   if (typeof pointer !== "object" || pointer === null || Array.isArray(pointer)) throw invalid("must be a JSON object");
diff --git a/packages/runs/tests/refusal-redaction.test.mjs b/packages/runs/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..93feb3b3d
--- /dev/null
+++ b/packages/runs/tests/refusal-redaction.test.mjs
@@ -0,0 +1,34 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { RunsError, readActivePointer } from '../src/index.mjs';
+test('release pointer JSON refusal names only the file', t => {
+  const root = scratch(t), file = write(join(root, 'state/active.json'));
+  assert.throws(() => readActivePointer(root), safe(file, RunsError, { exitCode: 2 }));
+});
diff --git a/packages/seat/src/seat.mjs b/packages/seat/src/seat.mjs
index 9a8f76476..37d7c4650 100644
--- a/packages/seat/src/seat.mjs
+++ b/packages/seat/src/seat.mjs
@@ -15,6 +15,7 @@
 //          Sessions live in <seatDir>/.pi/agent/sessions.
 // Anything else is layout "unknown" and records nulls; nothing is guessed.
 
+import { parseJsonFileText } from "../../organization/src/util.mjs";
 import { existsSync, readFileSync, mkdirSync, writeFileSync, renameSync, statSync, realpathSync } from "node:fs";
 import { join, basename, dirname, isAbsolute, resolve } from "node:path";
 import { homedir } from "node:os";
@@ -53,9 +54,9 @@ export function loadDataRoot(path = defaultConfigPath()) {
   if (!existsSync(path)) throw new SeatError(`config not found: ${path}`);
   let raw;
   try {
-    raw = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new SeatError(`config is not valid JSON: ${path} (${err.message})`);
+    raw = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new SeatError(`config is not valid JSON: ${path}`);
   }
   if (!raw || typeof raw !== "object" || Array.isArray(raw)) throw new SeatError(`config is not an object: ${path}`);
   if (typeof raw.dataRoot !== "string" || !isAbsolute(raw.dataRoot)) throw new SeatError(`config.dataRoot must be an absolute path: ${path}`);
@@ -202,9 +203,9 @@ export function readRegistration(seats, seat, layout) {
   if (!existsSync(path)) return null;
   let parsed;
   try {
-    parsed = JSON.parse(readFileSync(path, "utf8"));
-  } catch (err) {
-    throw new SeatError(`registration is not valid JSON: ${path} (${err.message})`);
+    parsed = parseJsonFileText(readFileSync(path, "utf8"), path);
+  } catch {
+    throw new SeatError(`registration is not valid JSON: ${path}`);
   }
   try {
     const record = validateRegistration(parsed);
diff --git a/packages/seat/tests/refusal-redaction.test.mjs b/packages/seat/tests/refusal-redaction.test.mjs
new file mode 100644
index 000000000..33b922648
--- /dev/null
+++ b/packages/seat/tests/refusal-redaction.test.mjs
@@ -0,0 +1,34 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join } from 'node:path';
+const secret = 'sk-test-NOT-A-SECRET-1234';
+// JSON.parse quotes a prefix near this fault on Node 26; check partial leaks too.
+const malformed = secret;
+function scratch(t) {
+  const root = mkdtempSync(join(tmpdir(), 'r3-'));
+  t.after(() => rmSync(root, { recursive: true, force: true }));
+  return root;
+}
+function write(file, text = malformed) {
+  mkdirSync(dirname(file), { recursive: true });
+  writeFileSync(file, text, { mode: 0o600 });
+  return file;
+}
+function safe(label, ErrorType, properties = {}) {
+  return error => {
+    assert.ok(error instanceof ErrorType);
+    for (const [key, value] of Object.entries(properties)) assert.equal(error[key], value);
+    assert.ok(error.message.includes(label), error.message);
+    assert.doesNotMatch(error.message, /sk-test|Unexpected token/);
+    assert.doesNotMatch(error.stack, /sk-test/);
+    assert.equal(error.cause, undefined);
+    return true;
+  };
+}
+import { SeatError, loadDataRoot, readRegistration, registrationPath } from '../src/seat.mjs';
+for (const kind of ['config', 'registration']) test(`${kind} JSON refusal names only the file`, t => {
+  const root = scratch(t), file = write(kind === 'config' ? join(root, 'config.json') : registrationPath(root, 'builder', 'repo'));
+  assert.throws(() => kind === 'config' ? loadDataRoot(file) : readRegistration(root, 'builder', 'repo'), safe(file, SeatError, { exitCode: 2 }));
+});
diff --git a/scripts/case2-precheck.sh b/scripts/case2-precheck.sh
index cb2693dcc..0c1d06a3b 100755
--- a/scripts/case2-precheck.sh
+++ b/scripts/case2-precheck.sh
@@ -193,9 +193,10 @@ try {
   readNotifyConfig(system.dataRoot, id);
   say("NOTIFY", "ok");
 } catch (e) { say("NOTIFY", "bad", e.message.split("\n")[0]); }
+const { parseJsonFileText } = await import(`${repo}/packages/organization/src/util.mjs`);
 const file = businessFilePath(id);
 let raw;
-try { raw = JSON.parse(readFileSync(file, "utf8")); } catch (e) { say("BUSINESS", "bad", `cannot read ${file}: ${e.code ?? e.message}`); process.exit(0); }
+try { raw = parseJsonFileText(readFileSync(file, "utf8"), file); } catch (e) { say("BUSINESS", "bad", `cannot read ${file}: ${e.code ?? "not valid JSON"}`); process.exit(0); }
 const library = Object.entries(raw?.projects ?? {}).filter(([, p]) => p && p.kind === "library").map(([k]) => k);
 if (library.length) say("LIBRARY", library.join(","));
 let b;
diff --git a/scripts/mosaic-task.mjs b/scripts/mosaic-task.mjs
index d6d35a87d..d3659a200 100755
--- a/scripts/mosaic-task.mjs
+++ b/scripts/mosaic-task.mjs
@@ -27,6 +27,7 @@
  *   - No secrets in mission/task data or run records.
  */
 
+import { parseJsonFileText } from "../packages/organization/src/util.mjs";
 import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
@@ -74,9 +75,9 @@ function readJsonFile(file, what) {
   }
   let document;
   try {
-    document = JSON.parse(fs.readFileSync(file, "utf8"));
-  } catch (error) {
-    fail(2, `${what} is not valid JSON (${file}): ${error.message}`);
+    document = parseJsonFileText(fs.readFileSync(file, "utf8"), file, what);
+  } catch {
+    fail(2, `${what} is not valid JSON (${file})`);
   }
   return document;
 }