fix: keep long frontmatter values on a single line

src/specify_cli/agents.py

@@ -157,7 +157,11 @@ def render_frontmatter(fm: dict) -> str:
             return ""
 
         yaml_str = yaml.dump(
-            fm, default_flow_style=False, sort_keys=False, allow_unicode=True
+            fm,
+            default_flow_style=False,
+            sort_keys=False,
+            allow_unicode=True,
+            width=float("inf"),
         )
         return f"---\n{yaml_str}---\n"
 

tests/test_extensions.py

@@ -17,6 +17,7 @@
 import tempfile
 import shutil
 import tomllib
+import yaml
 from contextlib import contextmanager
 from pathlib import Path
 from datetime import datetime, timezone
@@ -2996,6 +2997,30 @@ def test_render_frontmatter_unicode(self):
         assert "Prüfe Konformität" in output
         assert "\\u" not in output
 
+    def test_render_frontmatter_keeps_long_description_on_one_line(self):
+        """A long description must not be folded across lines.
+
+        PyYAML wraps plain scalars at ~80 columns by default, which splits a
+        long ``description`` onto a continuation line. The YAML stays valid,
+        but the rendered frontmatter then differs in shape from the
+        hand-written core command templates, where ``description`` is always a
+        single line -- and consumers that read frontmatter line-wise see a
+        truncated description followed by a stray line.
+        """
+        long_description = (
+            "Execute the implementation plan by processing and executing all "
+            "tasks defined in tasks.md"
+        )
+        frontmatter = {"name": "speckit-implement", "description": long_description}
+
+        registrar = CommandRegistrar()
+        output = registrar.render_frontmatter(frontmatter)
+
+        assert f"description: {long_description}\n" in output
+
+        body = output.split("---\n")[1]
+        assert yaml.safe_load(body)["description"] == long_description
+
     def test_adjust_script_paths_does_not_mutate_input(self):
         """Path adjustments should not mutate caller-owned frontmatter dicts."""
         from specify_cli.agents import CommandRegistrar as AgentCommandRegistrar