Bound copy-edit prompt context

Whitelist and truncate staged operation context before it reaches the local agent prompt.

AI assistance: Implemented and validated with OpenAI Codex under maintainer authorization.

skill/scripts/live-copy-edit-agent.mjs

@@ -14,6 +14,7 @@ import path from 'node:path';
 import { createRequire } from 'node:module';
 
 const DEFAULT_TIMEOUT_MS = 60_000;
+const BATCH_OP_TEXT_LIMIT = 240;
 const require = createRequire(import.meta.url);
 
 export function buildCopyEditBatchPrompt(batch, { cwd = process.cwd() } = {}) {
@@ -311,18 +312,59 @@ function compactBatchOp(op) {
     contextRef: op.contextRef,
     tag: op.tag,
     elementId: op.elementId,
-    classes: op.classes,
+    classes: compactBatchStringList(op.classes, 24),
     originalText: op.originalText,
     newText: op.newText,
     deleted: op.deleted === true || undefined,
-    sourceHint: op.sourceHint,
+    sourceHint: normalizeBatchSourceHint(op.sourceHint),
     leaf: compactContextForBatch(op.leaf),
-    nearbyEditableTexts: Array.isArray(op.nearbyEditableTexts) ? op.nearbyEditableTexts.slice(0, 8) : [],
+    nearbyEditableTexts: compactNearbyBatchTexts(op.nearbyEditableTexts),
     container: compactContextForBatch(op.container),
-    contextHints: Array.isArray(op.contextHints) ? op.contextHints.slice(0, 12) : [],
+    contextHints: compactBatchStringList(op.contextHints, 12),
   };
 }
 
+function normalizeBatchSourceHint(hint) {
+  if (!hint || typeof hint !== 'object') return null;
+  let line = Number.isFinite(Number(hint.line)) ? Number(hint.line) : null;
+  let column = Number.isFinite(Number(hint.column)) ? Number(hint.column) : null;
+  if ((!line || !column) && typeof hint.loc === 'string') {
+    const match = hint.loc.match(/^(\d+)(?::(\d+))?/);
+    if (match) {
+      line = Number(match[1]);
+      if (match[2]) column = Number(match[2]);
+    }
+  }
+  return {
+    file: compactBatchString(hint.file) || '',
+    loc: compactBatchString(hint.loc) || '',
+    line,
+    column,
+  };
+}
+
+function compactNearbyBatchTexts(items) {
+  return (Array.isArray(items) ? items : [])
+    .slice(0, 8)
+    .map((item) => typeof item === 'string' ? { text: truncate(item, BATCH_OP_TEXT_LIMIT) } : {
+      ref: compactBatchString(item?.ref),
+      tag: compactBatchString(item?.tag),
+      classes: compactBatchStringList(item?.classes, 24),
+      text: compactBatchString(item?.text),
+    });
+}
+
+function compactBatchStringList(items, limit) {
+  return (Array.isArray(items) ? items : [])
+    .slice(0, limit)
+    .filter((item) => typeof item === 'string')
+    .map((item) => truncate(item, BATCH_OP_TEXT_LIMIT));
+}
+
+function compactBatchString(value) {
+  return typeof value === 'string' ? truncate(value, BATCH_OP_TEXT_LIMIT) : undefined;
+}
+
 function compactContextForBatch(value) {
   if (!value || typeof value !== 'object') return value || null;
   return {

tests/live-copy-edit-agent.test.mjs

@@ -51,6 +51,49 @@ describe('live-copy-edit-agent', () => {
     assert.match(prompt, /Return ONLY JSON/);
   });
 
+  it('bounds and whitelists operation context in batch prompts', () => {
+    const huge = 'Z'.repeat(50_000);
+    const prompt = buildCopyEditBatchPrompt({
+      pageUrl: '/',
+      entries: [{
+        id: 'bounded',
+        pageUrl: '/',
+        ops: [{
+          classes: [huge],
+          originalText: 'Old',
+          newText: 'New',
+          sourceHint: {
+            file: 'src/App.jsx',
+            loc: '12:3',
+            nested: { payload: huge },
+          },
+          nearbyEditableTexts: [{
+            ref: 'body>main>span',
+            tag: 'span',
+            classes: ['label'],
+            text: huge,
+            extra: huge,
+          }],
+          contextHints: [huge],
+        }],
+      }],
+    });
+
+    const serializedBatch = prompt.split('Staged copy-edit batch:\n').pop();
+    const op = JSON.parse(serializedBatch).entries[0].ops[0];
+    assert.ok(prompt.length < 20_000, `expected compact prompt, got ${prompt.length} characters`);
+    assert.ok(op.classes[0].length < 400);
+    assert.deepEqual(op.sourceHint, {
+      file: 'src/App.jsx',
+      loc: '12:3',
+      line: 12,
+      column: 3,
+    });
+    assert.deepEqual(Object.keys(op.nearbyEditableTexts[0]).sort(), ['classes', 'ref', 'tag', 'text']);
+    assert.ok(op.nearbyEditableTexts[0].text.length < 400);
+    assert.ok(op.contextHints[0].length < 400);
+  });
+
   it('parses partial batch results', () => {
     assert.deepEqual(
       parseCopyEditBatchResult('{"status":"partial","appliedEntryIds":["a"],"failed":[{"entryId":"b","reason":"ambiguous"}],"files":["src/page.js"]}'),