Host: Codex CLI — This skill was designed for Claude Code and adapted for Codex. Cross-reference commands use installed skill names in Codex rather than /octo:* slash commands. Use the active Codex shell and subagent tools. Do not claim a provider, model, or host subagent is available until the current session exposes it. For host tool equivalents, see skills/blocks/codex-host-adapter.md.

Design Document Lineage

Overview

Persist design documents from brainstorming and planning sessions with branch tracking, revision chains, and cross-session discoverability. Design docs are immutable after creation -- new revisions supersede prior versions rather than editing in place.

Storage Location

All design documents are stored under:

~/.claude-octopus/designs/<project-slug>/

The project slug is derived from the current git repository name or working directory basename:

SLUG=$(basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)")
DESIGNS_DIR="${HOME}/.claude-octopus/designs/${SLUG}"
mkdir -p "$DESIGNS_DIR"

Filename Format

Design documents follow a strict naming convention:

{user}-{branch}-design-{datetime}.md

Where:

• {user} -- the current OS username ($USER or whoami)
• {branch} -- the current git branch, sanitized (slashes replaced with dashes)
• {datetime} -- ISO 8601 compact timestamp (YYYYMMDD-HHmmss)

Example:

chris-feature-auth-refactor-design-20260321-143022.md

Resolution:

BRANCH=$(git rev-parse --abbrev-ref HEAD 2>/dev/null | tr '/' '-' || echo "no-branch")
DATETIME=$(date -u +"%Y%m%d-%H%M%S")
FILENAME="${USER}-${BRANCH}-design-${DATETIME}.md"

Design Document Template

Each design document contains YAML frontmatter followed by structured sections.

Frontmatter Metadata

branch: feature/auth-refactor
user: chris
created: 2026-03-21T14:30:22Z
supersedes: chris-feature-auth-refactor-design-20260320-091500.md

Fields:

• branch -- the git branch at time of creation
• user -- the OS username who created the document
• created -- ISO 8601 timestamp of creation
• supersedes -- filename of the prior design document this revision replaces (omitted if this is the first design for the branch)

Document Sections

# Design: [Title]

## Problem Statement
[What problem does this design solve? Why does it matter?]

## Constraints
[Technical, timeline, resource, or organizational constraints that bound the solution space.]

## Approaches Considered
[List each approach evaluated, with brief pros/cons for each.]

### Approach A: [Name]
- **Pros:** ...
- **Cons:** ...

### Approach B: [Name]
- **Pros:** ...
- **Cons:** ...

## Recommendation
[Which approach is recommended and why. Include the key trade-off that drove the decision.]

## Open Questions
[Unresolved questions that may affect implementation or require follow-up.]

Step 1: Save Design

After a brainstorm, planning, or define workflow produces design output, save it to the standard location with metadata.

SLUG=$(basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)")
DESIGNS_DIR="${HOME}/.claude-octopus/designs/${SLUG}"
mkdir -p "$DESIGNS_DIR"

BRANCH=$(git rev-parse --abbrev-ref HEAD 2>/dev/null | tr '/' '-' || echo "no-branch")
DATETIME=$(date -u +"%Y%m%d-%H%M%S")
FILENAME="${USER}-${BRANCH}-design-${DATETIME}.md"
FILEPATH="${DESIGNS_DIR}/${FILENAME}"

cat > "$FILEPATH" <<EOF
branch: $(git rev-parse --abbrev-ref HEAD 2>/dev/null || echo "no-branch")
user: ${USER}
created: $(date -u +"%Y-%m-%dT%H:%M:%SZ")
${SUPERSEDES:+supersedes: ${SUPERSEDES}}

# Design: [Title]

## Problem Statement
[Content from brainstorm/planning session]

## Constraints
[Identified constraints]

## Approaches Considered
[Evaluated approaches]

## Recommendation
[Selected approach and rationale]

## Open Questions
[Unresolved items]
EOF

Design docs are read-only after creation. To revise a design, create a new document with a supersedes reference to the prior version.

Step 2: Discover Prior Designs

Before writing a new design, search for related prior designs using keyword matching.

SLUG=$(basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)")
DESIGNS_DIR="${HOME}/.claude-octopus/designs/${SLUG}"

# Search for designs matching keywords (case-insensitive)
KEYWORDS="auth refactor"
grep -li "$KEYWORDS" "${DESIGNS_DIR}"/*.md 2>/dev/null | head -10

Constraints:

• Keyword search is limited to 10 results to avoid overwhelming context
• Search is case-insensitive via grep -li
• Only searches within the current project slug's directory

When prior designs are found, present them to the user:

Found 2 prior designs related to "auth refactor":
  1. chris-feature-auth-refactor-design-20260320-091500.md (2026-03-20)
  2. chris-main-design-20260315-140000.md (2026-03-15)

Would you like to review any of these before creating a new design?

Step 3: Link Revision Chain

If a prior design exists for the same branch, the new design document includes a supersedes field in its frontmatter pointing to the prior filename.

BRANCH=$(git rev-parse --abbrev-ref HEAD 2>/dev/null | tr '/' '-' || echo "no-branch")

# Find the most recent design for this branch
PRIOR=$(ls -t "${DESIGNS_DIR}"/*-${BRANCH}-design-*.md 2>/dev/null | head -1)

if [[ -n "$PRIOR" ]]; then
  SUPERSEDES=$(basename "$PRIOR")
fi

This creates a linked chain of revisions:

v3 (supersedes: v2) -> v2 (supersedes: v1) -> v1 (no supersedes)

To walk the full revision history for a branch:

current="$FILENAME"
while [[ -n "$current" ]]; do
  echo "$current"
  current=$(grep '^supersedes:' "${DESIGNS_DIR}/${current}" 2>/dev/null | sed 's/supersedes: *//' || true)
done

Step 4: Cross-Session Discovery

Downstream commands (deliver, review, develop) auto-discover design context by checking the designs directory before starting work.

SLUG=$(basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)")
DESIGNS_DIR="${HOME}/.claude-octopus/designs/${SLUG}"
BRANCH=$(git rev-parse --abbrev-ref HEAD 2>/dev/null | tr '/' '-' || echo "no-branch")

# Find designs for current branch
BRANCH_DESIGNS=$(ls -t "${DESIGNS_DIR}"/*-${BRANCH}-design-*.md 2>/dev/null | head -3)

if [[ -n "$BRANCH_DESIGNS" ]]; then
  echo "Design context found for branch ${BRANCH}:"
  for design in $BRANCH_DESIGNS; do
    echo "  - $(basename "$design")"
  done
  # Read the most recent design for context
  LATEST_DESIGN=$(echo "$BRANCH_DESIGNS" | head -1)
  DESIGN_CONTEXT=$(<"$LATEST_DESIGN")
fi

Downstream skills should check for designs before starting work:

• flow-discover: Check for existing designs to avoid duplicate research
• flow-define: Incorporate prior design constraints into requirements
• flow-develop: Read the recommended approach from the latest design
• skill-brainstorm: Surface prior designs as starting context

Caps and Limits

• Max 50 design docs per project slug -- when the limit is reached, warn the user and suggest archiving old designs
• Keyword search limited to 10 results -- prevents context overload
• Design doc template max 500 lines -- encourages concise, actionable designs

Cap enforcement:

DOC_COUNT=$(ls "${DESIGNS_DIR}"/*.md 2>/dev/null | wc -l | tr -d ' ')
if [[ "$DOC_COUNT" -ge 50 ]]; then
  echo "Warning: ${DOC_COUNT} design docs in ${DESIGNS_DIR}. Consider archiving old designs."
fi

Integration Notes

Works With

• flow-discover -- Design docs capture research findings for persistence
• flow-define -- Design constraints feed into requirement definitions
• skill-brainstorm -- Brainstorm output can be saved as a design document
• skill-thought-partner -- Exploration sessions can produce design artifacts

Downstream Discovery

• flow-develop -- Reads latest design before implementation
• flow-deliver -- References design decisions during review
• skill-code-review -- Checks implementation against design recommendations

Immutability Rule

Design docs are read-only after creation. To update a design:

1. Create a new design document
2. Set supersedes to the prior document's filename
3. The prior document remains unchanged for audit trail

This ensures a complete history of design evolution is always available.