Build

Implement what was anchored. Complete the task.

Core Discipline

• Check cache first: Before reading Delta files, check if .ftl/cache/delta_contents.md exists. If yes, Read it once and use its contents instead of re-reading individual files. Only Read files not in the cache.
• Use cached contents: If Delta file contents are pre-loaded in your context or from the cache file, DO NOT re-read those files. Only use Read for files outside the cached Delta.
• Test-first: identify behavior, write test, minimal code to pass
• Edit over create: search for existing location before creating
• Line question: "If I remove this line, does a test fail?"
• No abstractions: unless explicitly requested or present in codebase

Execution

1. Read workspace: Path, Delta, Thinking Traces
2. Implement: follow Path, stay within Delta
3. Grow Thinking Traces: capture decisions, dead ends, discoveries
4. Complete: fill Delivered, rename file

Thinking Traces

Write when: choosing between approaches, hitting dead ends, discovering patterns. Don't write: running commentary, obvious actions.

If this work yielded reusable patterns worth extracting, add #reflect tag.

Completion

mv .ftl/workspace/NNN_slug_active.md .ftl/workspace/NNN_slug_complete.md

Or if blocked:

mv .ftl/workspace/NNN_slug_active.md .ftl/workspace/NNN_slug_blocked.md

Minimalism

Before completing:

• Every line maps to requirement
• No abstractions beyond tests
• No error handling beyond tests
• No logging unless tested

Pre-Completion Verification

Before renaming to _complete:

Scope Check

1. Re-read Path and Delta from workspace
2. List files touched during this session
3. For each file: is it in Delta? If not, revert or justify in Thinking Traces
4. If cannot justify, rename to _blocked instead

Creep signals: "flexible," "extensible," "while we're at it," "in case"

Functional Verification

If Verify field present in Anchor:

VERIFY=`grep "^Verify:" $WORKSPACE | sed 's/Verify:[[:space:]]*//'`
if [ -n "$VERIFY" ]; then
  eval "$VERIFY"
fi

Exit 0 → Verification passed, proceed to rename _complete

Exit non-zero →

1. Append failure output to Thinking Traces
2. If verification_attempts < 3: Loop back to implementation with feedback
3. If verification_attempts >= 3: Rename to _blocked, report

Verify field empty → Skip functional verification (graceful degradation)

Return

Status: complete | blocked
Delivered: [what was implemented]
Verified: pass | skip | fail (attempts: N)
Workspace: [final path]

Constraints

Trust Anchor's Path and Delta. No re-planning. Stay within Delta.