feat(presets): Composition strategies (prepend, append, wrap) for templates, commands, and scripts

presets/ARCHITECTURE.md

@@ -41,6 +41,24 @@ The resolution is implemented three times to ensure consistency:
 - **Bash**: `resolve_template()` in `scripts/bash/common.sh`
 - **PowerShell**: `Resolve-Template` in `scripts/powershell/common.ps1`
 
+### Composition Strategies
+
+Templates, commands, and scripts support a `strategy` field that controls how a preset's content is combined with lower-priority content instead of fully replacing it:
+
+| Strategy | Description | Templates | Commands | Scripts |
+|----------|-------------|-----------|----------|---------|
+| `replace` (default) | Fully replaces lower-priority content | ✓ | ✓ | ✓ |
+| `prepend` | Places content before lower-priority content (separated by a blank line) | ✓ | ✓ | — |
+| `append` | Places content after lower-priority content (separated by a blank line) | ✓ | ✓ | — |
+| `wrap` | Content contains `{CORE_TEMPLATE}` (templates/commands) or `$CORE_SCRIPT` (scripts) placeholder replaced with lower-priority content | ✓ | ✓ | ✓ |
+
+Composition is recursive — multiple composing presets chain. The `PresetResolver.resolve_content()` method walks the full priority stack bottom-up and applies each layer's strategy.
+
+Content resolution functions for composition:
+- **Python**: `PresetResolver.resolve_content()` in `src/specify_cli/presets.py` (templates, commands, and scripts)
+- **Bash**: `resolve_template_content()` in `scripts/bash/common.sh` (templates only; command/script composition is handled by the Python resolver)
+- **PowerShell**: `Resolve-TemplateContent` in `scripts/powershell/common.ps1` (templates only; command/script composition is handled by the Python resolver)
+
 ## Command Registration
 
 When a preset is installed with `type: "command"` entries, the `PresetManager` registers them into all detected agent directories using the shared `CommandRegistrar` from `src/specify_cli/agents.py`.

presets/README.md

@@ -61,7 +61,37 @@ specify preset add healthcare-compliance --priority 5  # overrides enterprise-sa
 specify preset add pm-workflow --priority 1            # overrides everything
 ```
 
-Presets **override**, they don't merge. If two presets both provide `spec-template`, the one with the lowest priority number wins entirely.
+Presets **override by default**, they don't merge. If two presets both provide `spec-template` with the default `replace` strategy, the one with the lowest priority number wins entirely. However, presets can use **composition strategies** to augment rather than replace content.
+
+### Composition Strategies
+
+Presets can declare a `strategy` per template to control how content is combined. The `name` field identifies which template to compose with in the priority stack, while `file` points to the actual content file (which can differ from the convention path `templates/<name>.md`):
+
+```yaml
+provides:
+  templates:
+    - type: "template"
+      name: "spec-template"
+      file: "templates/spec-addendum.md"
+      strategy: "append"        # adds content after the core template
+```
+
+| Strategy | Description |
+|----------|-------------|
+| `replace` (default) | Fully replaces the lower-priority template |
+| `prepend` | Places content **before** the resolved lower-priority template, separated by a blank line |
+| `append` | Places content **after** the resolved lower-priority template, separated by a blank line |
+| `wrap` | Content contains `{CORE_TEMPLATE}` placeholder (or `$CORE_SCRIPT` for scripts) replaced with the lower-priority content |
+
+**Supported combinations:**
+
+| Type | `replace` | `prepend` | `append` | `wrap` |
+|------|-----------|-----------|----------|--------|
+| **template** | ✓ (default) | ✓ | ✓ | ✓ |
+| **command** | ✓ (default) | ✓ | ✓ | ✓ |
+| **script** | ✓ (default) | — | — | ✓ |
+
+Multiple composing presets chain recursively. For example, a security preset with `prepend` and a compliance preset with `append` will produce: security header + core content + compliance footer.
 
 ## Catalog Management
 
@@ -108,13 +138,5 @@ See [scaffold/](scaffold/) for a scaffold you can copy to create your own preset
 
 The following enhancements are under consideration for future releases:
 
-- **Composition strategies** — Allow presets to declare a `strategy` per template instead of the default `replace`:
-
-  | Type | `replace` | `prepend` | `append` | `wrap` |
-  |------|-----------|-----------|----------|--------|
-  | **template** | ✓ (default) | ✓ | ✓ | ✓ |
-  | **command** | ✓ (default) | ✓ | ✓ | ✓ |
-  | **script** | ✓ (default) | — | — | ✓ |
-
-  For artifacts and commands (which are LLM directives), `wrap` injects preset content before and after the core template using a `{CORE_TEMPLATE}` placeholder (implemented). For scripts, `wrap` would run custom logic before/after the core script via a `$CORE_SCRIPT` variable (not yet implemented).
-- **Script overrides** — Enable presets to provide alternative versions of core scripts (e.g. `create-new-feature.sh`) for workflow customization. A `strategy: "wrap"` option could allow presets to run custom logic before/after the core script without fully replacing it.
+- **Structural merge strategies** — Parsing Markdown sections for per-section granularity (e.g., "replace only ## Security").
+- **Conflict detection** — `specify preset lint` / `specify preset doctor` for detecting composition conflicts.

presets/scaffold/preset.yml

@@ -32,6 +32,15 @@ provides:
   templates:
     # CUSTOMIZE: Define your template overrides
     # Templates are document scaffolds (spec-template.md, plan-template.md, etc.)
+    #
+    # Strategy options (optional, defaults to "replace"):
+    #   replace  - Fully replaces the lower-priority template (default)
+    #   prepend  - Places this content BEFORE the lower-priority template
+    #   append   - Places this content AFTER the lower-priority template
+    #   wrap     - Uses {CORE_TEMPLATE} placeholder (templates/commands) or
+    #              $CORE_SCRIPT placeholder (scripts), replaced with lower-priority content
+    #
+    # Note: Scripts only support "replace" and "wrap" strategies.
     - type: "template"
       name: "spec-template"
       file: "templates/spec-template.md"
@@ -45,6 +54,26 @@ provides:
     #   description: "Custom plan template"
     #   replaces: "plan-template"
 
+    # COMPOSITION EXAMPLES:
+    # The `file` field points to the content file (can differ from the
+    # convention path `templates/<name>.md`). The `name` field identifies
+    # which template to compose with in the priority stack.
+    #
+    # Append additional sections to an existing template:
+    # - type: "template"
+    #   name: "spec-template"
+    #   file: "templates/spec-addendum.md"
+    #   description: "Add compliance section to spec template"
+    #   strategy: "append"
+    #
+    # Wrap a command with preamble/sign-off:
+    # - type: "command"
+    #   name: "speckit.specify"
+    #   file: "commands/specify-wrapper.md"
+    #   description: "Wrap specify command with compliance checks"
+    #   strategy: "wrap"
+    #   # In the wrapper file, use {CORE_TEMPLATE} where the original content goes
+
     # OVERRIDE EXTENSION TEMPLATES:
     # Presets sit above extensions in the resolution stack, so you can
     # override templates provided by any installed extension.

scripts/bash/common.sh

@@ -320,8 +320,9 @@ try:
     with open(os.environ['SPECKIT_REGISTRY']) as f:
         data = json.load(f)
     presets = data.get('presets', {})
-    for pid, meta in sorted(presets.items(), key=lambda x: x[1].get('priority', 10)):
-        print(pid)
+    for pid, meta in sorted(presets.items(), key=lambda x: x[1].get('priority', 10) if isinstance(x[1], dict) else 10):
+        if isinstance(meta, dict) and meta.get('enabled', True) is not False:
+            print(pid)
 except Exception:
     sys.exit(1)
 " 2>/dev/null); then
@@ -373,3 +374,225 @@ except Exception:
     return 1
 }
 
+# Resolve a template name to composed content using composition strategies.
+# Reads strategy metadata from preset manifests and composes content
+# from multiple layers using prepend, append, or wrap strategies.
+#
+# Usage: CONTENT=$(resolve_template_content "template-name" "$REPO_ROOT")
+# Returns composed content string on stdout; exit code 1 if not found.
+resolve_template_content() {
+    local template_name="$1"
+    local repo_root="$2"
+    local base="$repo_root/.specify/templates"
+
+    # Collect all layers (highest priority first)
+    local -a layer_paths=()
+    local -a layer_strategies=()
+
+    # Priority 1: Project overrides (always "replace")
+    local override="$base/overrides/${template_name}.md"
+    if [ -f "$override" ]; then
+        layer_paths+=("$override")
+        layer_strategies+=("replace")
+    fi
+
+    # Priority 2: Installed presets (sorted by priority from .registry)
+    local presets_dir="$repo_root/.specify/presets"
+    if [ -d "$presets_dir" ]; then
+        local registry_file="$presets_dir/.registry"
+        local sorted_presets=""
+        if [ -f "$registry_file" ] && command -v python3 >/dev/null 2>&1; then
+            if sorted_presets=$(SPECKIT_REGISTRY="$registry_file" python3 -c "
+import json, sys, os
+try:
+    with open(os.environ['SPECKIT_REGISTRY']) as f:
+        data = json.load(f)
+    presets = data.get('presets', {})
+    for pid, meta in sorted(presets.items(), key=lambda x: x[1].get('priority', 10) if isinstance(x[1], dict) else 10):
+        if isinstance(meta, dict) and meta.get('enabled', True) is not False:
+            print(pid)
+except Exception:
+    sys.exit(1)
+" 2>/dev/null); then
+                if [ -n "$sorted_presets" ]; then
+                    local yaml_warned=false
+                    while IFS= read -r preset_id; do
+                        # Read strategy and file path from preset manifest
+                        local strategy="replace"
+                        local manifest_file=""
+                        local manifest="$presets_dir/$preset_id/preset.yml"
+                        if [ -f "$manifest" ] && command -v python3 >/dev/null 2>&1; then
+                            # Requires PyYAML; falls back to replace/convention if unavailable
+                            local result
+                            local py_stderr
+                            py_stderr=$(mktemp)
+                            result=$(SPECKIT_MANIFEST="$manifest" SPECKIT_TMPL="$template_name" python3 -c "
+import sys, os
+try:
+    import yaml
+except ImportError:
+    print('yaml_missing', file=sys.stderr)
+    print('replace\t')
+    sys.exit(0)
+try:
+    with open(os.environ['SPECKIT_MANIFEST']) as f:
+        data = yaml.safe_load(f)
+    for t in data.get('provides', {}).get('templates', []):
+        if t.get('name') == os.environ['SPECKIT_TMPL'] and t.get('type', 'template') == 'template':
+            print(t.get('strategy', 'replace') + '\t' + t.get('file', ''))
+            sys.exit(0)
+    print('replace\t')
+except Exception:
+    print('replace\t')
+" 2>"$py_stderr")
+                            local parse_status=$?
+                            if [ $parse_status -eq 0 ] && [ -n "$result" ]; then
+                                IFS=$'\t' read -r strategy manifest_file <<< "$result"
+                                strategy=$(printf '%s' "$strategy" | tr '[:upper:]' '[:lower:]')
+                            fi
+                            if [ "$yaml_warned" = false ] && grep -q 'yaml_missing' "$py_stderr" 2>/dev/null; then
+                                echo "Warning: PyYAML not available; composition strategies may be ignored" >&2
+                                yaml_warned=true
+                            fi
+                            rm -f "$py_stderr"
+                        fi
+                        # Try manifest file path first, then convention path
+                        local candidate=""
+                        if [ -n "$manifest_file" ]; then
+                            # Reject absolute paths and parent traversal
+                            case "$manifest_file" in
+                                /*|*../*|../*) manifest_file="" ;;
+                            esac
+                        fi
+                        if [ -n "$manifest_file" ]; then
+                            local mf="$presets_dir/$preset_id/$manifest_file"
+                            [ -f "$mf" ] && candidate="$mf"
+                        fi
+                        if [ -z "$candidate" ]; then
+                            local cf="$presets_dir/$preset_id/templates/${template_name}.md"
+                            [ -f "$cf" ] && candidate="$cf"
+                        fi
+                        if [ -n "$candidate" ]; then
+                            layer_paths+=("$candidate")
+                            layer_strategies+=("$strategy")
+                        fi
+                    done <<< "$sorted_presets"
+                fi
+            else
+                # python3 failed — fall back to unordered directory scan (replace only)
+                for preset in "$presets_dir"/*/; do
+                    [ -d "$preset" ] || continue
+                    local candidate="$preset/templates/${template_name}.md"
+                    if [ -f "$candidate" ]; then
+                        layer_paths+=("$candidate")
+                        layer_strategies+=("replace")
+                    fi
+                done
+            fi
+        else
+            # No python3 or registry — fall back to unordered directory scan (replace only)
+            for preset in "$presets_dir"/*/; do
+                [ -d "$preset" ] || continue
+                local candidate="$preset/templates/${template_name}.md"
+                if [ -f "$candidate" ]; then
+                    layer_paths+=("$candidate")
+                    layer_strategies+=("replace")
+                fi
+            done
+        fi
+    fi
+
+    # Priority 3: Extension-provided templates (always "replace")
+    local ext_dir="$repo_root/.specify/extensions"
+    if [ -d "$ext_dir" ]; then
+        for ext in "$ext_dir"/*/; do
+            [ -d "$ext" ] || continue
+            case "$(basename "$ext")" in .*) continue;; esac
+            local candidate="$ext/templates/${template_name}.md"
+            if [ -f "$candidate" ]; then
+                layer_paths+=("$candidate")
+                layer_strategies+=("replace")
+            fi
+        done
+    fi
+
+    # Priority 4: Core templates (always "replace")
+    local core="$base/${template_name}.md"
+    if [ -f "$core" ]; then
+        layer_paths+=("$core")
+        layer_strategies+=("replace")
+    fi
+
+    local count=${#layer_paths[@]}
+    [ "$count" -eq 0 ] && return 1
+
+    # Check if any layer uses a non-replace strategy
+    local has_composition=false
+    for s in "${layer_strategies[@]}"; do
+        [ "$s" != "replace" ] && has_composition=true && break
+    done
+
+    # If the top (highest-priority) layer is replace, it wins entirely —
+    # lower layers are irrelevant regardless of their strategies.
+    if [ "${layer_strategies[0]}" = "replace" ]; then
+        cat "${layer_paths[0]}"
+        return 0
+    fi
+
+    if [ "$has_composition" = false ]; then
+        cat "${layer_paths[0]}"
+        return 0
+    fi
+
+    # Find the effective base: scan from highest priority (index 0) downward
+    # to find the nearest replace layer. Only compose layers above that base.
+    local base_idx=-1
+    local i
+    for (( i=0; i<count; i++ )); do
+        if [ "${layer_strategies[$i]}" = "replace" ]; then
+            base_idx=$i
+            break
+        fi
+    done
+
+    if [ $base_idx -lt 0 ]; then
+        return 1  # no base layer found
+    fi
+
+    # Read the base content; compose layers above the base (higher priority)
+    local content
+    content=$(cat "${layer_paths[$base_idx]}"; printf x)
+    content="${content%x}"
+
+    for (( i=base_idx-1; i>=0; i-- )); do
+        local path="${layer_paths[$i]}"
+        local strat="${layer_strategies[$i]}"
+        local layer_content
+        # Preserve trailing newlines
+        layer_content=$(cat "$path"; printf x)
+        layer_content="${layer_content%x}"
+
+        case "$strat" in
+            replace) content="$layer_content" ;;
+            prepend) content="$(printf '%s\n\n%s' "$layer_content" "$content")" ;;
+            append)  content="$(printf '%s\n\n%s' "$content" "$layer_content")" ;;
+            wrap)
+                case "$layer_content" in
+                    *'{CORE_TEMPLATE}'*) ;;
+                    *) echo "Error: wrap strategy missing {CORE_TEMPLATE} placeholder" >&2; return 1 ;;
+                esac
+                while [[ "$layer_content" == *'{CORE_TEMPLATE}'* ]]; do
+                    local before="${layer_content%%\{CORE_TEMPLATE\}*}"
+                    local after="${layer_content#*\{CORE_TEMPLATE\}}"
+                    layer_content="${before}${content}${after}"
+                done
+                content="$layer_content"
+                ;;
+            *) echo "Error: unknown strategy '$strat'" >&2; return 1 ;;
+        esac
+    done
+
+    printf '%s' "$content"
+    return 0
+}
+