Decision Eval — automated scoring for architectural alternatives

Invoke after architect proposes 2+ variants, before creating gate:arch.

When to invoke

Invoke this skill when ALL of these are true:

1. An ADR (docs/decisions/ADR-*.md) or ARCH doc (docs/architecture/ARCH-*.md) contains a section with 2 or more named alternatives (look for ## Alternatives Considered, ## Options, or bold-prefixed options like **Option A:**)
2. The architect has not yet created gate:arch
3. The user has not said "skip scoring", "no scoring", or "skip decision-eval"
4. project_size in PROJECT.md is NOT nano

Skip silently (do not even mention) if any condition fails.

How to invoke

Read the most recent ADR or ARCH doc to confirm 2+ variants exist, then spawn the decision-scorer agent with the file path as context:

# Identify target document
TARGET=$(ls -t docs/decisions/ADR-*.md 2>/dev/null | head -1)
[ -z "$TARGET" ] && TARGET=$(ls -t docs/architecture/ARCH-*.md 2>/dev/null | head -1)

# Confirm 2+ variants
VARIANT_COUNT=$(grep -cE "^\*\*[A-Za-z]|^### [A-Za-z]|^- \*\*[A-Za-z]" "$TARGET" 2>/dev/null || echo 0)

If VARIANT_COUNT >= 2, dispatch the agent:

Agent: decision-scorer
Context: <TARGET file path>
Task: Score the architectural variants in <TARGET> against .great_cto/PROJECT.md criteria.
      Save output to docs/decisions/.

Output location

The decision-scorer agent saves results to:

docs/decisions/DECISION-<slug>-<YYYYMMDD>.md

After the agent completes, read the output file and surface the recommendation to the architect:

Decision scoring complete:
  Recommended: <variant name> (<score>/5.00)
  Runner-up:   <variant name> (<score>/5.00)
  Full report: docs/decisions/DECISION-<slug>-<YYYYMMDD>.md

Architect: review the scoring rationale before accepting or overriding the recommendation.

Skip conditions

Output nothing and proceed to the next step if:

• project_size: nano in PROJECT.md
• Fewer than 2 variants found in the ADR/ARCH doc
• User message contains "skip scoring" or "skip decision-eval" or "no scoring"
• The target document is a bug-fix or docs-only ADR (check title for "fix:", "docs:", "chore:")

Integration with architect workflow

This skill sits between Step 4 (Write ADR) and Step 5 (Create gate:arch) in agents/architect.md. Architect invokes it by name:

Invoke skill: decision-eval

After scoring completes, architect may:

• Accept the recommendation → proceed to gate:arch with the recommended option
• Override the recommendation → document rationale in the ADR under a new ## Scoring Override section before creating gate:arch