diff --git a/.changeset/purpose-marker-punctuation.md b/.changeset/purpose-marker-punctuation.md
new file mode 100644
index 0000000000..ae4102edd4
--- /dev/null
+++ b/.changeset/purpose-marker-punctuation.md
@@ -0,0 +1,8 @@
+---
+'@fission-ai/openspec': patch
+---
+
+Fix `validate --strict` reporting `PURPOSE_IS_PLACEHOLDER` for a Purpose that opens with the ordinary word "Todo" followed by prose, as in Spanish ("Todo el…") and Portuguese ("Todo o…") specs ([#1897](https://github.com/Fission-AI/OpenSpec/issues/1897)).
+
+- Case now separates the marker from the word. `TBD`/`TODO` in capitals is still a placeholder marker whatever follows it, so `TODO write this later` is still reported.
+- In any other case it counts as a marker only when followed by the end of the Purpose, a line break, or marker punctuation (`todo -`, `tbd.`), so an authored Spanish or Portuguese sentence is not reported.
diff --git a/src/core/validation/purpose-placeholder.ts b/src/core/validation/purpose-placeholder.ts
index 5fa3060df0..2f411a3dfc 100644
--- a/src/core/validation/purpose-placeholder.ts
+++ b/src/core/validation/purpose-placeholder.ts
@@ -39,15 +39,35 @@ export interface PurposePlaceholderIssue {
 }
 
 /**
- * A `TBD` or `TODO` opening the Purpose. The lookahead keeps it off a longer
- * word that merely begins with those letters, like "TBDs" or "TODOs", while
- * still allowing the punctuation a marker is usually written with: `TODO:`,
- * `TBD -`. It rejects any letter, digit or combining mark rather than only the
- * ASCII ones `\b` knows about, because a Purpose is prose and prose is not
- * always written in Latin script - `TBD` followed by an Arabic-Indic digit is
- * as much a longer word as `TBDs` is.
+ * A `TBD` or `TODO` opening the Purpose.
+ *
+ * `WORD_END` keeps the marker off a longer word that merely begins with those
+ * letters, like "TBDs" or "TODOs", while still allowing the punctuation a
+ * marker is usually written with: `TODO:`, `TBD -`. It rejects any letter,
+ * digit or combining mark rather than only the ASCII ones `\b` knows about,
+ * because a Purpose is prose and prose is not always written in Latin script -
+ * `TBD` followed by an Arabic-Indic digit is as much a longer word as `TBDs`.
+ *
+ * Case is what separates the marker from the word. `TODO` shouted in capitals
+ * is the marker whatever follows it, so `TODO write this later` is still an
+ * unwritten Purpose. Written in any other case it is only a marker when
+ * punctuation or the end of the line says so, because `todo` is an extremely
+ * frequent sentence opener in Spanish ("Todo el...") and Portuguese ("Todo
+ * o..."), and ordinary prose in those languages is not a placeholder. That
+ * keeps the lowercase forms an agent really does leave behind - `todo - write
+ * this later`, `tbd.` - reported, without reading a Spanish sentence as one.
  */
-const LEADING_MARKER = /^(?:TBD|TODO)(?![\p{L}\p{N}\p{M}_])/iu;
+const WORD_END = '(?![\\p{L}\\p{N}\\p{M}_])';
+const MARKER_PUNCTUATION = '(?=[ \\t]*(?:$|\\n|[:\\-\u2013\u2014.,;()\\[\\]{}]))';
+
+/** `TBD`/`TODO` in capitals: the marker, whatever follows it. */
+const LEADING_MARKER_SHOUTED = new RegExp(`^(?:TBD|TODO)${WORD_END}`, 'u');
+
+/** Any other case: a marker only when punctuation or the line end says so. */
+const LEADING_MARKER_PUNCTUATED = new RegExp(
+  `^(?:TBD|TODO)${WORD_END}${MARKER_PUNCTUATION}`,
+  'iu'
+);
 
 const PURPOSE_HEADER = /^ {0,3}##(?!#)[ \t]+Purpose[ \t]*$/i;
 const TOP_LEVEL_HEADER = /^ {0,3}#{1,2}(?!#)[ \t]+/;
@@ -104,7 +124,8 @@ export function findPurposePlaceholderIssue(
   // that is nothing but a fenced block reduces to the same empty text here, and
   // is left to the brevity and empty-Purpose rules for the same reason.
   const prose = unfencedLines(overview).join('\n').trim();
-  const leading = LEADING_MARKER.test(prose);
+  const leading =
+    LEADING_MARKER_SHOUTED.test(prose) || LEADING_MARKER_PUNCTUATED.test(prose);
   if (!leading && generatedPlaceholderPrefixIndex(prose) === undefined) return null;
   // Which rule matched decides where the placeholder is, so the locator is told.
   // When both match the leading marker wins: it sits at or above the generated
diff --git a/test/core/purpose-placeholder.test.ts b/test/core/purpose-placeholder.test.ts
index aee7b9cbc8..cb78ce9e57 100644
--- a/test/core/purpose-placeholder.test.ts
+++ b/test/core/purpose-placeholder.test.ts
@@ -164,6 +164,43 @@ describe('findPurposePlaceholderIssue', () => {
       expect(findPurposePlaceholderIssue('   \n  ', specWith(''))).toBeNull();
     });
 
+    it('does not report the Spanish word "Todo" opening authored prose', () => {
+      // `todo` is an extremely frequent sentence opener in Spanish ("Todo
+      // el…") and Portuguese ("Todo o…"). A marker is written `TODO:`,
+      // `TODO -`, or alone on its line - never `Todo` followed by prose.
+      for (const purpose of [
+        'Todo el conocimiento del producto vive del otro lado, en el repo hermano.',
+        'Todo o catálogo é carregado a partir do repositório irmão.',
+      ]) {
+        expect(findPurposePlaceholderIssue(purpose, specWith(purpose))).toBeNull();
+      }
+    });
+
+    it('still reports a marker alone on its line above placeholder prose', () => {
+      const purpose = 'TODO\nfill this in once the capability settles down.';
+      expect(findPurposePlaceholderIssue(purpose, specWith(purpose))).not.toBeNull();
+    });
+
+    it('still reports a shouted TODO opening placeholder prose without punctuation', () => {
+      // Case is what separates the marker from the Spanish word. In capitals
+      // it is the marker whatever follows it, so requiring punctuation must
+      // not let the plainest unwritten Purpose of all through.
+      for (const purpose of [
+        'TODO write this once the capability settles down.',
+        'TBD pending the design review that has not happened yet.',
+      ]) {
+        expect(findPurposePlaceholderIssue(purpose, specWith(purpose))).not.toBeNull();
+      }
+    });
+
+    it('does not report lowercase Spanish prose either', () => {
+      // The reporter is the capitals, not the position: `todo` uncapitalised
+      // opens a sentence just as often, and is just as much authored prose.
+      const purpose =
+        'todo el conocimiento del producto vive del otro lado, en el repo hermano.';
+      expect(findPurposePlaceholderIssue(purpose, specWith(purpose))).toBeNull();
+    });
+
     it('does not report an ordinary short Purpose, which PURPOSE_TOO_BRIEF covers', () => {
       expect(findPurposePlaceholderIssue('Does stuff.', specWith('Does stuff.'))).toBeNull();
     });