CANP-WP-0002 T03: composition by reference, two kinds

T01 had already delivered half of composition without naming it: a derived
default binds an input to a prompt dependency, which is transclusion — run
package B, use its output. What was missing was the deterministic half.

`include` inlines another package's rendered template as text. No model is
involved, so the reference CLI can actually perform it, and a shared preamble,
rubric or style block becomes a versioned package instead of copied text. This
is the concrete way to honor INTENT principle 9 without any runtime. `derive`
stays as it was. Both are input defaults, so composition reuses the resolution
machinery rather than adding a second one.

No template inheritance. Four of this repo's own documents argue against it:
INTENT principle 3 (hidden context defeats reuse), section 19's "make package
contents visible before execution", section 17's requirement that behavior
changes produce a new version, and the non-goal on range resolution.

Version selectors: an exact pin is the expected form, with `any`, `newest` and
`>= X.Y.Z` as explicit opt-ins so looseness is written rather than implied by
absence. Selectors are evaluated per dependency against what is available —
no solver, no cross-dependency constraint satisfaction — which is what keeps
them outside the range-resolution non-goal, and the spec says so.

Also defines `type` (template | fragment), which appeared once in the section 4
manifest surface and was specified nowhere.

Spec: 3.2 (type), 5.1 (inclusion resolution rule, renumbered), 6.1 (included
default), 10.1 and 10.2 (new), 18 (rules 14-16), 21.

Reference CLI: validate_version_selector, select_version,
prompt_dependencies replacing prompt_dependency_ids,
check_composition_reference, CatalogComposer with cycle detection, and
resolve_inputs gaining composer= and inherited=. Tests 21 -> 42.

Examples: house-style is a real fragment package; pqrst-estimate composes it
and is bumped 0.1.0 -> 0.2.0 per section 17.

Fixes an ordering bug found while testing: inputs resolved before parameters,
so an included package could not see the including package's parameters and
silently fell back to its own defaults — the fragment rendered tone=neutral
where the including package said blunt. Parameters now resolve first; the
report still lists inputs first.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bjefh8NUiEiahN4JLwoSKM

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 388925@bnt-lap001
Assistant-Session: 3507023f-e0fd-4a1e-9d90-a0d4217d1502

reference/README.md

@@ -69,6 +69,8 @@ rather than resolved by guessing.
 - `add` copies a package directly to catalog.
 - `search`, `show`, `resolve`, and `render` operate on catalog packages, and
   print qualified `<registry>:<id>` references.
+- `include` defaults are satisfied (inclusion is deterministic); `derive`
+  defaults are reported, not run. Inclusion cycles are detected and named.
 - An optional `registry.yaml` names a registry and records namespace claims.
   `publish` warns when a namespace is declared `closed` — it cannot
   authenticate a publisher, and says so rather than implying it checked.

reference/canned_prompts.py

@@ -97,37 +97,65 @@ def declared_names(manifest: dict[str, Any]) -> set[str]:
 
 
 def input_default_kind(item: dict[str, Any]) -> str:
-    """Classify an input's default as 'none', 'static', or 'derived' (§ 6.1)."""
+    """Classify a default as 'none', 'static', 'derived', or 'included' (§ 6.1)."""
     if "default" not in item:
         return "none"
     default = item["default"]
-    if isinstance(default, dict) and "derive" in default:
-        return "derived"
+    if isinstance(default, dict):
+        if "derive" in default and "include" in default:
+            return "conflict"
+        if "derive" in default:
+            return "derived"
+        if "include" in default:
+            return "included"
     return "static"
 
 
-def prompt_dependency_ids(manifest: dict[str, Any]) -> set[str]:
+def prompt_dependencies(manifest: dict[str, Any]) -> dict[str, dict[str, Any]]:
     dependencies = manifest.get("dependencies") or {}
     if not isinstance(dependencies, dict):
         raise CannedPromptError("dependencies must be a mapping")
     prompts = dependencies.get("prompts") or []
     if not isinstance(prompts, list):
         raise CannedPromptError("dependencies.prompts must be a list")
-    ids: set[str] = set()
+    declared: dict[str, dict[str, Any]] = {}
     for entry in prompts:
         if isinstance(entry, str):
-            ids.add(entry)
+            declared[entry] = {"id": entry}
         elif isinstance(entry, dict) and isinstance(entry.get("id"), str):
-            ids.add(entry["id"])
+            if "version" in entry:
+                validate_version_selector(
+                    entry["version"], f"dependency {entry['id']!r}"
+                )
+            declared[entry["id"]] = entry
         else:
             raise CannedPromptError(
                 "each prompt dependency must be an id string or a mapping with a string id"
             )
-    return ids
+    return declared
 
 
-def validate_input_default(item: dict[str, Any], dependency_ids: set[str]) -> None:
-    """Validation rules 11-13 of § 18."""
+def check_composition_reference(
+    name: str, reference: str, field: str, declared: dict[str, dict[str, Any]]
+) -> None:
+    if not reference.strip():
+        raise CannedPromptError(f"input {name!r}: {field} reference is empty")
+    if reference not in declared:
+        raise CannedPromptError(
+            f"input {name!r} {field}s {reference!r}, which is not declared "
+            "in dependencies.prompts"
+        )
+    if "version" not in declared[reference]:
+        raise CannedPromptError(
+            f"input {name!r} {field}s {reference!r}, so that dependency must "
+            "declare a version (§ 10.1)"
+        )
+
+
+def validate_input_default(
+    item: dict[str, Any], declared: dict[str, dict[str, Any]]
+) -> None:
+    """Validation rules 11-16 of § 18."""
     kind = input_default_kind(item)
     if kind == "none":
         return
@@ -139,16 +167,23 @@ def validate_input_default(item: dict[str, Any], dependency_ids: set[str]) -> No
         )
     if kind == "static":
         return
+    if kind == "conflict":
+        raise CannedPromptError(
+            f"input {name!r}: a default declares at most one of 'include' or 'derive'"
+        )
+
+    if kind == "included":
+        include = item["default"]["include"]
+        if not isinstance(include, str):
+            raise CannedPromptError(
+                f"input {name!r}: include must name a declared prompt dependency"
+            )
+        check_composition_reference(name, include, "include", declared)
+        return
 
     derive = item["default"]["derive"]
     if isinstance(derive, str):
-        if not derive.strip():
-            raise CannedPromptError(f"input {name!r}: derive reference is empty")
-        if derive not in dependency_ids:
-            raise CannedPromptError(
-                f"input {name!r} derives from {derive!r}, which is not declared "
-                "in dependencies.prompts"
-            )
+        check_composition_reference(name, derive, "derive", declared)
         return
     if isinstance(derive, dict):
         prompt = derive.get("prompt")
@@ -204,9 +239,9 @@ def validate_package(package_dir: Path) -> dict[str, Any]:
 
     names = declared_names(manifest)
 
-    dependency_ids = prompt_dependency_ids(manifest)
+    declared = prompt_dependencies(manifest)
     for item in manifest.get("inputs") or []:
-        validate_input_default(item, dependency_ids)
+        validate_input_default(item, declared)
 
     template = template_path.read_text(encoding="utf-8")
     placeholders = set(PLACEHOLDER_RE.findall(template))
@@ -302,6 +337,45 @@ def catalog_package_path(catalog: Path, registry: str, package_id: str, version:
     return id_path(catalog / check_registry_name(registry), package_id) / version
 
 
+def validate_version_selector(value: Any, where: str) -> str:
+    """A semver literal, `any`, `newest`, or a `>=` lower bound (§ 10.1)."""
+    if not isinstance(value, str) or not value.strip():
+        raise CannedPromptError(f"{where}: version must be a non-empty string")
+    selector = value.strip()
+    if selector in ("any", "newest"):
+        return selector
+    compact = selector.replace(" ", "")
+    if compact.startswith(">="):
+        if not SEMVER_RE.match(compact[2:]):
+            raise CannedPromptError(f"{where}: {value!r} is not a valid lower bound")
+        return compact
+    if not SEMVER_RE.match(selector):
+        raise CannedPromptError(
+            f"{where}: unsupported version selector {value!r}; expected a semver "
+            "literal, 'any', 'newest', or '>= X.Y.Z'"
+        )
+    return selector
+
+
+def select_version(available: list[str], selector: str | None) -> str | None:
+    """Pick a version from `available` (newest first) per a § 10.1 selector.
+
+    Each dependency is selected independently against what is present. There is
+    no constraint solving across a dependency graph; that stays a non-goal.
+    """
+    if not available:
+        return None
+    if selector is None or selector in ("any", "newest"):
+        return available[0]
+    if selector.startswith(">="):
+        floor = parse_semver(selector[2:])
+        for version in available:
+            if parse_semver(version) >= floor:
+                return version
+        return None
+    return selector if selector in available else None
+
+
 def parse_semver(value: str) -> tuple[int, int, int, str]:
     match = SEMVER_RE.match(value)
     if not match:
@@ -545,15 +619,59 @@ class Resolution:
     underivable: list[str] = field(default_factory=list)
 
 
-def resolve_inputs(manifest: dict[str, Any], raw_values: dict[str, str]) -> Resolution:
+def resolve_inputs(
+    manifest: dict[str, Any],
+    raw_values: dict[str, str],
+    composer: "Composer | None" = None,
+    inherited: dict[str, Any] | None = None,
+) -> Resolution:
     """Resolve inputs and parameters per § 5.1.
 
-    This tool never calls a model, so a derived default is satisfied only by its
-    static fallback `value`. An input with a derived default and no fallback is
-    reported as underivable rather than silently rendered as empty.
+    `composer`, when supplied, satisfies `include` defaults by rendering the
+    included package (§ 10.2). Inclusion is deterministic, so a tool that can
+    render can satisfy it; derivation is not, and this tool never calls a model,
+    so a derived default is satisfied only by its static fallback `value`.
+
+    `inherited` carries the including package's already-resolved values into an
+    included package (§ 10.2). Those values are used as-is rather than coerced,
+    and do not count as caller-supplied.
     """
     result = Resolution()
+    inherited = inherited or {}
     known: set[str] = set()
+    declared = prompt_dependencies(manifest)
+
+    def compose(name: str, item: dict[str, Any]) -> None:
+        default = item["default"]
+        reference = default["include"]
+        if composer is not None:
+            entry = declared.get(reference) or {}
+            result.values[name] = composer(reference, entry.get("version"), result.values)
+            result.origins[name] = f"included from {reference}"
+            return
+        if "value" in default:
+            result.values[name] = default["value"]
+            result.origins[name] = "fallback (not included)"
+        else:
+            result.origins[name] = "unresolved (included, no fallback)"
+            result.underivable.append(name)
+
+    # Parameters resolve first: a composed input inherits the including
+    # package's resolved values (§ 10.2), so those must already be settled.
+    parameters = manifest.get("parameters") or {}
+    for name, spec in parameters.items():
+        known.add(name)
+        if name in raw_values:
+            result.values[name] = coerce_value(raw_values[name], spec)
+            result.origins[name] = "supplied"
+        elif name in inherited:
+            result.values[name] = inherited[name]
+            result.origins[name] = "inherited"
+        elif "default" in spec:
+            result.values[name] = spec["default"]
+            result.origins[name] = "default"
+        else:
+            result.origins[name] = "unresolved (no default)"
 
     inputs = manifest.get("inputs") or []
     for item in inputs:
@@ -563,6 +681,10 @@ def resolve_inputs(manifest: dict[str, Any], raw_values: dict[str, str]) -> Reso
             result.values[name] = raw_values[name]
             result.origins[name] = "supplied"
             continue
+        if name in inherited:
+            result.values[name] = inherited[name]
+            result.origins[name] = "inherited"
+            continue
         if item.get("required", False):
             raise CannedPromptError(f"missing required input: {name}")
 
@@ -570,6 +692,8 @@ def resolve_inputs(manifest: dict[str, Any], raw_values: dict[str, str]) -> Reso
         if kind == "static":
             result.values[name] = item["default"]
             result.origins[name] = "default"
+        elif kind == "included":
+            compose(name, item)
         elif kind == "derived":
             default = item["default"]
             if "value" in default:
@@ -581,17 +705,10 @@ def resolve_inputs(manifest: dict[str, Any], raw_values: dict[str, str]) -> Reso
         else:
             result.origins[name] = "unresolved (optional, no default)"
 
-    parameters = manifest.get("parameters") or {}
-    for name, spec in parameters.items():
-        known.add(name)
-        if name in raw_values:
-            result.values[name] = coerce_value(raw_values[name], spec)
-            result.origins[name] = "supplied"
-        elif "default" in spec:
-            result.values[name] = spec["default"]
-            result.origins[name] = "default"
-        else:
-            result.origins[name] = "unresolved (no default)"
+    # Report inputs before parameters regardless of resolution order.
+    ordered = {item["name"]: result.origins[item["name"]] for item in inputs}
+    ordered.update({name: result.origins[name] for name in parameters})
+    result.origins = ordered
 
     unknown = sorted(set(raw_values) - known)
     if unknown:
@@ -604,6 +721,79 @@ def resolve_values(manifest: dict[str, Any], raw_values: dict[str, str]) -> dict
     return resolve_inputs(manifest, raw_values).values
 
 
+class CatalogComposer:
+    """Satisfies `include` defaults from the catalog (§ 10.2).
+
+    Inclusion is text composition: the included package is rendered and its text
+    is inlined. No model is involved, so this is deterministic.
+    """
+
+    def __init__(self, catalog: Path) -> None:
+        self.catalog = catalog
+        self._stack: list[str] = []
+
+    def __call__(
+        self, reference: str, selector: str | None, outer_values: dict[str, Any]
+    ) -> str:
+        if reference in self._stack:
+            raise CannedPromptError(
+                "inclusion cycle: " + " -> ".join([*self._stack, reference])
+            )
+
+        registry, package_id = parse_reference(reference)
+        names = (
+            [registry]
+            if registry is not None
+            else [
+                name
+                for name in catalog_registries(self.catalog)
+                if versions_at(id_path(self.catalog / name, package_id))
+            ]
+        )
+        if len(names) > 1:
+            raise CannedPromptError(
+                f"included package {package_id} is present in more than one registry: "
+                + ", ".join(f"{name}:{package_id}" for name in names)
+                + " — qualify the dependency id"
+            )
+        if not names:
+            raise CannedPromptError(f"included package not found: {reference}")
+
+        base = id_path(self.catalog / names[0], package_id)
+        version = select_version(versions_at(base), selector)
+        if version is None:
+            raise CannedPromptError(
+                f"included package {reference}: no version satisfies {selector!r}"
+            )
+
+        package_dir = base / version
+        manifest = validate_package(package_dir)
+        template_path = safe_relative_file(package_dir, manifest["template"], "template")
+
+        self._stack.append(reference)
+        try:
+            inner = resolve_inputs(manifest, {}, composer=self, inherited=outer_values)
+        except CannedPromptError as exc:
+            if str(exc).startswith("inclusion cycle:"):
+                raise
+            raise CannedPromptError(f"while including {reference}: {exc}") from exc
+        finally:
+            self._stack.pop()
+
+        text = template_path.read_text(encoding="utf-8")
+        used = set(PLACEHOLDER_RE.findall(text))
+        missing = sorted(used - set(inner.values))
+        if missing:
+            raise CannedPromptError(
+                f"included package {reference} has unresolved inputs the including "
+                "package does not supply: " + ", ".join(missing)
+            )
+        return render_template(text, inner.values)
+
+
+Composer = CatalogComposer
+
+
 def render_template(template: str, values: dict[str, Any]) -> str:
     def replace(match: re.Match[str]) -> str:
         name = match.group(1)
@@ -625,7 +815,7 @@ def cmd_render(args: argparse.Namespace) -> None:
     manifest = validate_package(package_dir)
     template_path = safe_relative_file(package_dir, manifest["template"], "template")
     raw = supplied_values(args.set_values)
-    resolution = resolve_inputs(manifest, raw)
+    resolution = resolve_inputs(manifest, raw, composer=CatalogComposer(catalog))
 
     template = template_path.read_text(encoding="utf-8")
     used = set(PLACEHOLDER_RE.findall(template))
@@ -647,7 +837,7 @@ def cmd_resolve(args: argparse.Namespace) -> None:
     package_dir, _ = resolve_installed(catalog, args.id, args.version)
     manifest = validate_package(package_dir)
     raw = supplied_values(args.set_values)
-    resolution = resolve_inputs(manifest, raw)
+    resolution = resolve_inputs(manifest, raw, composer=CatalogComposer(catalog))
 
     if args.json:
         print(
@@ -664,12 +854,13 @@ def cmd_resolve(args: argparse.Namespace) -> None:
         return
 
     width = max((len(name) for name in resolution.origins), default=0)
+    origin_width = max((len(o) for o in resolution.origins.values()), default=0)
     for name, origin in resolution.origins.items():
         if name in resolution.values:
             preview = str(resolution.values[name]).replace("\n", " ")
             if len(preview) > 48:
                 preview = preview[:45] + "..."
-            print(f"{name:<{width}}  {origin:<32}  {preview}")
+            print(f"{name:<{width}}  {origin:<{origin_width}}  {preview}")
         else:
             print(f"{name:<{width}}  {origin}")
     if resolution.underivable:

reference/tests/test_canned_prompts.py

@@ -336,3 +336,171 @@ def test_legacy_catalog_layout_is_reported(tmp_path: Path) -> None:
     (legacy / "prompt.md").write_text("{{ greeting }}\n", encoding="utf-8")
     with pytest.raises(cp.CannedPromptError, match="pre-registry-scoped"):
         cp.resolve_installed(catalog, "practice/thing", None)
+
+
+# --- version selectors (§ 10.1) ---
+
+AVAILABLE = ["2.1.0", "2.0.0", "1.5.0", "1.0.0"]
+
+
+@pytest.mark.parametrize(
+    "available,selector,expected",
+    [
+        (AVAILABLE, None, "2.1.0"),
+        (AVAILABLE, "any", "2.1.0"),
+        (AVAILABLE, "newest", "2.1.0"),
+        (AVAILABLE, "1.5.0", "1.5.0"),
+        (AVAILABLE, ">=2.0.0", "2.1.0"),
+        (AVAILABLE, "9.9.9", None),
+        (AVAILABLE, ">=9.9.9", None),
+        (["1.5.0", "1.0.0"], ">=1.2.0", "1.5.0"),
+        ([], "newest", None),
+    ],
+)
+def test_select_version(available, selector, expected) -> None:
+    assert cp.select_version(available, selector) == expected
+
+
+@pytest.mark.parametrize("bad", ["^1.0.0", "~1.2", "1.x", ">=nope", "", "latest"])
+def test_range_syntax_is_rejected(bad) -> None:
+    with pytest.raises(cp.CannedPromptError):
+        cp.validate_version_selector(bad, "dep")
+
+
+# --- composition (§ 10.2) ---
+
+FRAGMENT = """\
+format: canned-prompt/v0.1
+id: style/house
+name: House Style
+version: 1.0.0
+summary: Shared style block.
+type: fragment
+template: prompt.md
+parameters:
+  tone:
+    type: enum
+    values: [neutral, blunt]
+    default: neutral
+"""
+
+COMPOSER = """\
+format: canned-prompt/v0.1
+id: review/change
+name: Change Review
+version: 1.0.0
+summary: Composes the shared style block.
+template: prompt.md
+dependencies:
+  prompts:
+    - id: style/house
+      version: 1.0.0
+inputs:
+  - name: house_style
+    required: false
+    default:
+      include: style/house
+parameters:
+  tone:
+    type: enum
+    values: [neutral, blunt]
+    default: blunt
+"""
+
+
+def place(catalog: Path, registry: str, package_id: str, version: str,
+          manifest: str, template: str) -> None:
+    dst = cp.catalog_package_path(catalog, registry, package_id, version)
+    dst.mkdir(parents=True)
+    (dst / "prompt.yaml").write_text(manifest, encoding="utf-8")
+    (dst / "prompt.md").write_text(template, encoding="utf-8")
+
+
+@pytest.fixture()
+def composed(tmp_path: Path) -> Path:
+    catalog = tmp_path / "catalog"
+    place(catalog, "local", "style/house", "1.0.0", FRAGMENT, "Tone is {{ tone }}.")
+    place(catalog, "local", "review/change", "1.0.0", COMPOSER, "S: {{ house_style }}")
+    return catalog
+
+
+def test_include_inlines_rendered_template(composed: Path) -> None:
+    package_dir, _ = cp.resolve_installed(composed, "review/change", None)
+    manifest = cp.validate_package(package_dir)
+    resolution = cp.resolve_inputs(manifest, {}, composer=cp.CatalogComposer(composed))
+    assert resolution.values["house_style"] == "Tone is blunt."
+    assert resolution.origins["house_style"] == "included from style/house"
+
+
+def test_include_inherits_outer_parameters(composed: Path) -> None:
+    """The fragment's own default is neutral; the including package says blunt."""
+    package_dir, _ = cp.resolve_installed(composed, "review/change", None)
+    manifest = cp.validate_package(package_dir)
+    resolution = cp.resolve_inputs(
+        manifest, {"tone": "neutral"}, composer=cp.CatalogComposer(composed)
+    )
+    assert resolution.values["house_style"] == "Tone is neutral."
+
+
+def test_include_without_composer_falls_back_to_unresolved(composed: Path) -> None:
+    package_dir, _ = cp.resolve_installed(composed, "review/change", None)
+    manifest = cp.validate_package(package_dir)
+    resolution = cp.resolve_inputs(manifest, {})
+    assert resolution.underivable == ["house_style"]
+
+
+def test_inclusion_cycle_is_detected(tmp_path: Path) -> None:
+    catalog = tmp_path / "catalog"
+    for this, other in (("cyc/a", "cyc/b"), ("cyc/b", "cyc/a")):
+        manifest = (
+            "format: canned-prompt/v0.1\n"
+            f"id: {this}\nname: X\nversion: 1.0.0\nsummary: s\ntemplate: prompt.md\n"
+            f"dependencies:\n  prompts:\n    - id: {other}\n      version: 1.0.0\n"
+            f"inputs:\n  - name: other\n    required: false\n"
+            f"    default:\n      include: {other}\n"
+        )
+        place(catalog, "local", this, "1.0.0", manifest, "{{ other }}")
+    package_dir, _ = cp.resolve_installed(catalog, "cyc/a", None)
+    manifest = cp.validate_package(package_dir)
+    with pytest.raises(cp.CannedPromptError, match="inclusion cycle"):
+        cp.resolve_inputs(manifest, {}, composer=cp.CatalogComposer(catalog))
+
+
+def test_include_and_derive_together_is_rejected(tmp_path: Path) -> None:
+    pkg = write_pkg(
+        tmp_path / "p",
+        BASE
+        + """\
+dependencies:
+  prompts:
+    - id: style/house
+      version: 1.0.0
+inputs:
+  - name: greeting
+    required: false
+    default:
+      include: style/house
+      derive: style/house
+""",
+    )
+    with pytest.raises(cp.CannedPromptError, match="at most one of"):
+        cp.validate_package(pkg)
+
+
+def test_composed_dependency_must_declare_a_version(tmp_path: Path) -> None:
+    pkg = write_pkg(
+        tmp_path / "p",
+        BASE
+        + """\
+dependencies:
+  prompts:
+    - id: style/house
+inputs:
+  - name: greeting
+    required: false
+    default:
+      include: style/house
+""",
+    )
+    with pytest.raises(cp.CannedPromptError, match="must declare a version"):
+        cp.validate_package(pkg)