fix(integrations): stop frontmatter injection gluing onto a missing trailing newline

src/specify_cli/integrations/alquimia/__init__.py

@@ -152,7 +152,13 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if dash_count == 1 and stripped.startswith(f"{key}:"):
                 return content
 
-        # Inject before the closing --- of frontmatter
+        # Inject before the closing --- of frontmatter. Always emit a
+        # newline after the injected key so the key and the closing ---
+        # stay on separate lines even when the closing delimiter is the
+        # last line of the file with no trailing newline -- otherwise the
+        # injected text glues onto the "---" (e.g. "user-invocable: true---"),
+        # destroying the delimiter so a later call's pre-scan/injection
+        # never finds a second "---" and silently drops that key entirely.
         out: list[str] = []
         dash_count = 0
         injected = False
@@ -161,13 +167,7 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if stripped == "---":
                 dash_count += 1
                 if dash_count == 2 and not injected:
-                    if line.endswith("\r\n"):
-                        eol = "\r\n"
-                    elif line.endswith("\n"):
-                        eol = "\n"
-                    else:
-                        eol = ""
-                    out.append(f"{key}: {value}{eol}")
+                    out.append(f"{key}: {value}\n")
                     injected = True
             out.append(line)
         return "".join(out)

src/specify_cli/integrations/claude/__init__.py

@@ -173,7 +173,13 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if dash_count == 1 and stripped.startswith(f"{key}:"):
                 return content
 
-        # Inject before the closing --- of frontmatter
+        # Inject before the closing --- of frontmatter. Always emit a
+        # newline after the injected key so the key and the closing ---
+        # stay on separate lines even when the closing delimiter is the
+        # last line of the file with no trailing newline -- otherwise the
+        # injected text glues onto the "---" (e.g. "user-invocable: true---"),
+        # destroying the delimiter so a later call's pre-scan/injection
+        # never finds a second "---" and silently drops that key entirely.
         out: list[str] = []
         dash_count = 0
         injected = False
@@ -182,13 +188,7 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if stripped == "---":
                 dash_count += 1
                 if dash_count == 2 and not injected:
-                    if line.endswith("\r\n"):
-                        eol = "\r\n"
-                    elif line.endswith("\n"):
-                        eol = "\n"
-                    else:
-                        eol = ""
-                    out.append(f"{key}: {value}{eol}")
+                    out.append(f"{key}: {value}\n")
                     injected = True
             out.append(line)
         return "".join(out)

src/specify_cli/integrations/vibe/__init__.py

@@ -115,7 +115,13 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if dash_count == 1 and stripped.startswith(f"{key}:"):
                 return content
 
-        # Inject before the closing --- of frontmatter
+        # Inject before the closing --- of frontmatter. Always emit a
+        # newline after the injected key so the key and the closing ---
+        # stay on separate lines even when the closing delimiter is the
+        # last line of the file with no trailing newline -- otherwise the
+        # injected text glues onto the "---" (e.g. "user-invocable: true---"),
+        # destroying the delimiter so a later call's pre-scan/injection
+        # never finds a second "---" and silently drops that key entirely.
         out: list[str] = []
         dash_count = 0
         injected = False
@@ -124,13 +130,7 @@ def _inject_frontmatter_flag(content: str, key: str, value: str = "true") -> str
             if stripped == "---":
                 dash_count += 1
                 if dash_count == 2 and not injected:
-                    if line.endswith("\r\n"):
-                        eol = "\r\n"
-                    elif line.endswith("\n"):
-                        eol = "\n"
-                    else:
-                        eol = ""
-                    out.append(f"{key}: {value}{eol}")
+                    out.append(f"{key}: {value}\n")
                     injected = True
             out.append(line)
         return "".join(out)

tests/integrations/test_integration_alquimia.py

@@ -621,6 +621,45 @@ def test_skills_default_post_process_preserves_content_without_hooks(
         assert agy.post_process_skill_content(content) == content
 
 
+class TestAlquimiaInjectFrontmatterFlagNoTrailingNewline:
+    """`_inject_frontmatter_flag` must not corrupt content whose closing
+    frontmatter delimiter is the file's last line with no trailing newline.
+
+    `post_process_skill_content` calls this helper on content from
+    "external skill generators (presets, extensions)" (per the base
+    class's docstring) -- not guaranteed to end with a trailing newline.
+    Without a newline after the injected line, the injected text glues
+    onto the closing `---`, destroying the delimiter.
+    """
+
+    def test_single_call_keeps_delimiter_on_its_own_line(self):
+        from specify_cli.integrations.alquimia import AlquimiaAIIntegration
+
+        content = "---\nname: x\n---"
+        result = AlquimiaAIIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        assert result == "---\nname: x\nuser-invocable: true\n---"
+
+    def test_chained_calls_both_apply(self):
+        """The exact sequence `post_process_skill_content` runs: a second
+        injected key must still land, not be silently dropped because the
+        first call already destroyed the closing `---` line."""
+        from specify_cli.integrations.alquimia import AlquimiaAIIntegration
+
+        content = "---\nname: x\n---"
+        result = AlquimiaAIIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        result = AlquimiaAIIntegration._inject_frontmatter_flag(
+            result, "disable-model-invocation", "false"
+        )
+        assert result == (
+            "---\nname: x\nuser-invocable: true\n"
+            "disable-model-invocation: false\n---"
+        )
+
+
 class TestAlquimiaHookCommandNote:
     """Verify dot-to-hyphen normalization note is injected in hook sections."""
 

tests/integrations/test_integration_claude.py

@@ -591,6 +591,45 @@ def test_skills_default_post_process_preserves_content_without_hooks(self, tmp_p
         assert agy.post_process_skill_content(content) == content
 
 
+class TestClaudeInjectFrontmatterFlagNoTrailingNewline:
+    """`_inject_frontmatter_flag` must not corrupt content whose closing
+    frontmatter delimiter is the file's last line with no trailing newline.
+
+    `post_process_skill_content` calls this helper on content from
+    "external skill generators (presets, extensions)" (per its own
+    docstring) -- not guaranteed to end with a trailing newline. Without a
+    newline after the injected line, the injected text glues onto the
+    closing `---`, destroying the delimiter.
+    """
+
+    def test_single_call_keeps_delimiter_on_its_own_line(self):
+        from specify_cli.integrations.claude import ClaudeIntegration
+
+        content = "---\nname: x\n---"
+        result = ClaudeIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        assert result == "---\nname: x\nuser-invocable: true\n---"
+
+    def test_chained_calls_both_apply(self):
+        """The exact sequence `post_process_skill_content` runs: a second
+        injected key must still land, not be silently dropped because the
+        first call already destroyed the closing `---` line."""
+        from specify_cli.integrations.claude import ClaudeIntegration
+
+        content = "---\nname: x\n---"
+        result = ClaudeIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        result = ClaudeIntegration._inject_frontmatter_flag(
+            result, "disable-model-invocation", "false"
+        )
+        assert result == (
+            "---\nname: x\nuser-invocable: true\n"
+            "disable-model-invocation: false\n---"
+        )
+
+
 class TestClaudeForkContext:
     """Verify context: fork is injected only for commands listed in FORK_CONTEXT_COMMANDS."""
 

tests/integrations/test_integration_vibe.py

@@ -334,3 +334,42 @@ def test_all_skills_have_disable_model_invocation(self, tmp_path):
             assert parsed.get("disable-model-invocation") is False, (
                 f"{f.parent.name}/SKILL.md is missing disable-model-invocation: false in frontmatter"
             )
+
+
+class TestVibeInjectFrontmatterFlagNoTrailingNewline:
+    """`_inject_frontmatter_flag` must not corrupt content whose closing
+    frontmatter delimiter is the file's last line with no trailing newline.
+
+    `post_process_skill_content` calls this helper on content from
+    "external skill generators (presets, extensions)" (per the base
+    class's docstring) -- not guaranteed to end with a trailing newline.
+    Without a newline after the injected line, the injected text glues
+    onto the closing `---`, destroying the delimiter.
+    """
+
+    def test_single_call_keeps_delimiter_on_its_own_line(self):
+        from specify_cli.integrations.vibe import VibeIntegration
+
+        content = "---\nname: x\n---"
+        result = VibeIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        assert result == "---\nname: x\nuser-invocable: true\n---"
+
+    def test_chained_calls_both_apply(self):
+        """The exact sequence `post_process_skill_content` runs: a second
+        injected key must still land, not be silently dropped because the
+        first call already destroyed the closing `---` line."""
+        from specify_cli.integrations.vibe import VibeIntegration
+
+        content = "---\nname: x\n---"
+        result = VibeIntegration._inject_frontmatter_flag(
+            content, "user-invocable"
+        )
+        result = VibeIntegration._inject_frontmatter_flag(
+            result, "disable-model-invocation", "false"
+        )
+        assert result == (
+            "---\nname: x\nuser-invocable: true\n"
+            "disable-model-invocation: false\n---"
+        )