From cdd9a7d0e2b2153cec280f6f191e13d80c2dbb7c Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sat, 30 May 2026 19:42:19 +0000
Subject: [PATCH] fix(context): ignore non-string frontmatter title/description
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Some docs (e.g. Svelte 5's template-syntax pages) have unquoted YAML
frontmatter titles like `{@render ...}` or `{let/const ...}` that the
YAML parser reads as a flow-mapping object rather than a string. That
object propagated into a section's docTitle and was then passed to a
better-sqlite3 prepared statement as a positional argument, where it was
interpreted as a named-parameters bind object — leaving fewer values
than `?` placeholders and crashing the build with "Too few parameter
values were provided".

extractFrontmatter now keeps title/description only when they are
strings, falling back to the filename-derived title otherwise. This
unblocks publishing svelte@5.56.0 (and similarly-formatted docs).

https://claude.ai/code/session_01Dk6cdQKeX3Lr1eDoL1uTXM
---
 .changeset/curly-lions-cheer.md    |  5 +++++
 packages/context/src/build.test.ts | 21 +++++++++++++++++++++
 packages/context/src/build.ts      | 10 +++++++++-
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/curly-lions-cheer.md

diff --git a/.changeset/curly-lions-cheer.md b/.changeset/curly-lions-cheer.md
new file mode 100644
index 0000000..7f9a267
--- /dev/null
+++ b/.changeset/curly-lions-cheer.md
@@ -0,0 +1,5 @@
+---
+"@neuledge/context": patch
+---
+
+Ignore non-string `title`/`description` frontmatter values when parsing docs. Previously a frontmatter field that parsed to a non-string (e.g. an object) propagated into the document title and broke package building with "Too few parameter values were provided". Such values now fall back to the derived title instead of crashing the build.
diff --git a/packages/context/src/build.test.ts b/packages/context/src/build.test.ts
index a0f7841..2e8cb9f 100644
--- a/packages/context/src/build.test.ts
+++ b/packages/context/src/build.test.ts
@@ -27,6 +27,27 @@ Install the package.
     expect(result.frontmatter.description).toBe("Learn how to get started");
   });
 
+  it("ignores non-string frontmatter title (malformed YAML)", () => {
+    // Svelte 5's docs use unquoted titles like `{let/const ...}` that YAML
+    // parses into an object, which must not leak into docTitle (it would break
+    // SQLite parameter binding with "Too few parameter values were provided").
+    const source = `---
+title: {let/const ...}
+---
+
+## Declaration tags
+
+Some content about declaration tags.
+`;
+
+    const result = parseMarkdown(source, "docs/declaration-tags.md");
+
+    expect(result.frontmatter.title).toBeUndefined();
+    // docTitle falls back to the filename-derived title
+    expect(typeof result.sections[0]?.docTitle).toBe("string");
+    expect(result.sections[0]?.docTitle).toBe("declaration-tags");
+  });
+
   it("chunks content by h2 sections", () => {
     const source = `---
 title: Routing
diff --git a/packages/context/src/build.ts b/packages/context/src/build.ts
index 1651c44..96fceee 100644
--- a/packages/context/src/build.ts
+++ b/packages/context/src/build.ts
@@ -141,7 +141,15 @@ function extractFrontmatter(tree: Root): DocFrontmatter {
   if (!yamlNode) return {};
 
   try {
-    return parseYaml(yamlNode.value) as DocFrontmatter;
+    // Validate types rather than blindly casting: malformed frontmatter can
+    // parse title/description into non-strings (e.g. a bare value the YAML
+    // parser reads as a map), which later breaks SQLite parameter binding.
+    const data = parseYaml(yamlNode.value) as Record<string, unknown> | null;
+    return {
+      title: typeof data?.title === "string" ? data.title : undefined,
+      description:
+        typeof data?.description === "string" ? data.description : undefined,
+    };
   } catch {
     return {};
   }