Split Specifications Skill

Converts a single-file product spec ({{specs_dir}}/product_specs.md) into a directory-based format ({{specs_dir}}/product_specs/) for better organization and targeted context loading.

When to Use

• Automatically by design-product and source-product-specs-from-code when the single-file PRD crosses 500 lines or 15 features (feature sections matching ### \d+\.\d+)
• Manually when the user invokes /groundwork:split-specs

Step 0: Resolve Project Context

1. Monorepo check: Does .groundwork.yml exist at the repo root?
   • If yes → Is {{project_name}} non-empty?
     • If empty → Invoke Skill(skill="groundwork:select-project") to select a project, then restart this skill.
     • If set → Project is {{project_name}}, specs at {{specs_dir}}/.
   • If no → Continue (single-project repo).
2. Proceed with the resolved project context.

Step 1: Validate Preconditions

1. Check single file exists: {{specs_dir}}/product_specs.md must exist
   • If missing → output "No single-file PRD found at {{specs_dir}}/product_specs.md. Nothing to split." and stop.
2. Check directory does NOT exist: {{specs_dir}}/product_specs/ must not already exist
   • If it exists → output "PRD is already in directory format at {{specs_dir}}/product_specs/. Nothing to do." and stop.
3. Read the file and count lines and features (sections matching ^### \d+\.\d+).

Step 2: Split the File

Parse the single-file PRD into sections and write each to its own file under {{specs_dir}}/product_specs/.

Directory Structure

{{specs_dir}}/product_specs/
├── _index.md              # Header, metadata, and section 0 (EARS cheat sheet)
├── 01-product-context.md  # Section 1: Product context
├── 02-non-functional.md   # Section 2: Non-functional & cross-cutting requirements
├── 03-features/           # Section 3: One file per feature
│   ├── _index.md          # Section 3 header ("## 3) Feature list (living backlog)")
│   └── <feature-code>.md  # e.g., PRD-SRCH.md, PRD-AUTH.md
├── 04-traceability.md     # Section 4: Traceability
└── 05-open-questions.md   # Section 5: Open questions log

Parsing Rules

1. _index.md — Everything from the start of the file up to (but not including) ## 1). Include the YAML-style header block (Doc status, Last updated, Owner, Audience) and section 0 (EARS cheat sheet).
2. 01-product-context.md — From ## 1) up to (but not including) ## 2).
3. 02-non-functional.md — From ## 2) up to (but not including) ## 3).
4. 03-features/_index.md — The ## 3) heading line and any text before the first ### 3. subsection. Typically just:

   ## 3) Feature list (living backlog)

5. 03-features/<feature-code>.md — One file per ### 3.N subsection. The filename is derived from the feature's PRD code:
   • Extract the code from the heading, e.g., ### 3.1 Text Search (PRD-SRCH) → PRD-SRCH.md
   • If no code in parentheses, use a slug of the feature name: ### 3.5 Signature Display → signature-display.md
   • Preserve the full ### 3.N ... heading in the file
6. 04-traceability.md — From ## 4) up to (but not including) ## 5).
7. 05-open-questions.md — From ## 5) to the end of the file, or up to ## 6) if present. If there is a ## 6) (e.g., "Out of scope"), include it in 05-open-questions.md as well.

Edge Cases

• If a section is missing from the source file, skip that output file (don't create empty files).
• Preserve all horizontal rules (---) as they appear in the source.
• Preserve trailing newlines — each output file should end with a single newline.

Step 3: Delete the Single File

After all directory files are written and verified:

1. Verify — Read back _index.md and at least two feature files to confirm they look correct.
2. Delete — Remove {{specs_dir}}/product_specs.md using rm.
3. Confirm — Output a summary:

Split product_specs.md into directory format:
  {{specs_dir}}/product_specs/
  ├── _index.md
  ├── 01-product-context.md
  ├── 02-non-functional.md
  ├── 03-features/ (N feature files)
  ├── 04-traceability.md
  └── 05-open-questions.md

The single file has been removed. All skills (design-product, source-product-specs-from-code, etc.) already support directory mode.

Auto-Split Thresholds

When invoked automatically (not by the user), the caller has already verified that at least one threshold is crossed:

• Line count: wc -l on {{specs_dir}}/product_specs.md >= 500
• Feature count: Number of ### \d+\.\d+ headings >= 15

No user confirmation is needed — the split happens silently and the caller reports what happened.

When invoked manually by the user, skip threshold checks and split unconditionally.