fix(integrations): escape control characters in goose recipe YAML renderer (#3384)

* fix(integrations): escape control characters in goose recipe YAML renderer

YAML forbids C0 control characters (except tab and newline) and DEL in
every scalar form, and a bare CR acts as a line break inside a block
scalar. _render_yaml wrote the body verbatim into a |2 literal block
scalar, so such bodies produced recipes the YAML parser rejects. Detect
block-scalar-unsafe characters and fall back to an escaped double-quoted
scalar via yaml.safe_dump, mirroring the TOML renderer's fallback
strategy from #3341.

Fixes #3382

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(integrations): use sys.maxsize instead of float inf for yaml width

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(integrations): extend block-scalar guard to C1 controls and Unicode line breaks

YAML's printable set excludes C1 controls (U+0080-U+009F except NEL), and
YAML 1.1 treats NEL/LS/PS as line breaks inside a literal block scalar, so
bodies carrying any of these still produced unparseable recipes. Widen the
fallback guard to the full class and cover it in the regression loop.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(integrations): also treat surrogates and U+FFFE/U+FFFF as block-scalar unsafe

YAML's printable set also excludes lone UTF-16 surrogates and the
non-characters U+FFFE/U+FFFF; bodies carrying them still hit the literal
block path and produced unparseable recipes. Extend the guard and the
regression loop.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs(integrations): clarify YAML prompt serialization

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/specify_cli/integrations/base.py

@@ -1122,6 +1122,17 @@ class TomlIntegration(IntegrationBase):
 # YamlIntegration — YAML-format agents (Goose)
 # ---------------------------------------------------------------------------
 
+# Characters a YAML literal block scalar cannot carry: C0 controls other
+# than tab/LF (a bare CR acts as a line break inside the scalar), DEL, the
+# C1 range, lone UTF-16 surrogates, and the non-characters U+FFFE/U+FFFF.
+# NEL (U+0085) is YAML-printable but, like LS/PS (U+2028/U+2029), YAML 1.1
+# treats it as a line break, which corrupts the block scalar's structure
+# just the same, so all three are included.
+_YAML_BLOCK_SCALAR_UNSAFE = re.compile(
+    r"[\x00-\x08\x0b-\x1f\x7f-\x9f\u2028\u2029\ud800-\udfff\ufffe\uffff]"
+)
+
+
 class YamlIntegration(IntegrationBase):
     """Concrete base for integrations that use YAML recipe format.
 
@@ -1227,9 +1238,9 @@ class YamlIntegration(IntegrationBase):
     def _render_yaml(cls, title: str, description: str, body: str, source_id: str) -> str:
         """Render a YAML recipe file from title, description, and body.
 
-        Produces a Goose-compatible recipe with a literal block scalar
-        for the prompt content.  Uses ``yaml.safe_dump()`` for the
-        header fields to ensure proper escaping.
+        Produces a Goose-compatible recipe with a literal block scalar for
+        normal prompt content, or an escaped quoted scalar when control
+        characters require it. Uses ``yaml.safe_dump()`` for the header fields.
         """
         header = cls._build_yaml_header(title, description)
 
@@ -1240,6 +1251,23 @@ class YamlIntegration(IntegrationBase):
             default_flow_style=False,
         ).strip()
 
+        # YAML forbids C0 control characters (except tab and newline) and
+        # DEL in every scalar form, and a bare CR acts as a line break
+        # inside a block scalar. A literal block scalar emits such bytes
+        # verbatim, producing a recipe the YAML parser rejects, so fall
+        # back to an escaped double-quoted scalar for those bodies.
+        if _YAML_BLOCK_SCALAR_UNSAFE.search(body):
+            prompt_yaml = yaml.safe_dump(
+                {"prompt": body}, allow_unicode=True, default_style='"', width=sys.maxsize
+            ).strip()
+            lines = [
+                header_yaml,
+                prompt_yaml,
+                "",
+                f"# Source: {source_id}",
+            ]
+            return "\n".join(lines) + "\n"
+
         # Indent the body for YAML block scalar. Use an explicit indentation
         # indicator ("|2") rather than a bare "|": YAML infers a plain block
         # scalar's indentation from its first non-empty line, so a body whose

tests/integrations/test_integration_base_yaml.py

@@ -201,6 +201,36 @@ class YamlIntegrationTests:
         parsed = yaml.safe_load("\n".join(yaml_lines))
         assert parsed["prompt"].rstrip("\n") == body
 
+    def test_yaml_prompt_with_control_characters_stays_valid(self):
+        """A body containing control characters must still produce parseable YAML.
+
+        YAML forbids C0 control characters (except tab and newline), DEL,
+        C1 controls, lone surrogates and U+FFFE/U+FFFF in every scalar form,
+        and YAML 1.1 treats NEL (U+0085), LS (U+2028) and PS (U+2029) as
+        line breaks that corrupt a literal block scalar's structure. The
+        renderer falls back to an escaped double-quoted scalar for such
+        bodies."""
+        for ch in (
+            "\x08", "\x0c", "\x1b", "\x7f",
+            "\x80", "\x84", "\x85", "\x86", "\x9f",
+            "\u2028", "\u2029",
+            "\ud800", "\udfff", "\ufffe", "\uffff",
+        ):
+            body = f"before{ch}after\nsecond line"
+            rendered = YamlIntegration._render_yaml("Title", "Desc", body, "src")
+            parsed = yaml.safe_load(rendered)
+            assert parsed["prompt"].rstrip("\n") == body, f"char {ch!r} round-trip"
+
+    def test_yaml_prompt_with_bare_carriage_return_stays_valid(self):
+        """A bare CR (not part of CRLF) must not break the generated YAML.
+
+        Inside a block scalar a lone \r acts as a line break, corrupting
+        the document structure."""
+        body = "line1\rstill line1\nline2"
+        rendered = YamlIntegration._render_yaml("Title", "Desc", body, "src")
+        parsed = yaml.safe_load(rendered)
+        assert parsed["prompt"].rstrip("\n") == body
+
     def test_plan_command_has_no_context_placeholder(self, tmp_path):
         """The generated plan command must not carry a context-file placeholder.