spectra-parallel-spec

name	spectra-parallel-spec
description	TRANCE-only G3 evaluator-optimizer mode: fan out 2-4 perspective-diverse clean-context candidate specs, score with a bias-hardened evaluator, judge-merge into ONE spec, terminate at confidence ≥85% or hard cap 3 iterations. Read-only; never the default — runs ONLY when the cortex authorizes TRANCE.
metadata	{"methodology":"SPECTRA","phase":"TRANCE"}

SPECTRA — Parallel Spec Mode (G3 evaluator-optimizer)

This mode wraps the standard S→P→E→C→T→R→A cycle — it does NOT replace it. It operationalizes the G3 TRANCE form named in the nexus trance-matrix ("Generator + evaluator + termination gate; cap 3 iterations").

Activation — TRANCE-GATED (never default)

This mode is TRANCE-gated. Do NOT fan out candidate specs at standard tier; run the single-pass S→P→E→C→T→R→A cycle instead.

Activate ONLY when the cortex authorizes TRANCE — i.e. BOTH complexity AND stakes flags hold: complexity 10-12 STRATEGIC/CHANGE specs, multi-service architecture, or high-rework-risk system design. At standard tier, fall back to the normal cycle.

Read-vs-write safety

SPECTRA is READ-ONLY in every phase (D2), so the parallel generator branches are the explicitly-SAFE parallel-READ case — NO worktree isolation is required (R1-01). This is distinct from APIVR-Δ's parallel-WRITE, which does need worktree isolation.

The cycle: GENERATE → EVALUATE → JUDGE-MERGE → TERMINATE

1. GENERATE (perspective-diverse fan-out)

Fan out 2-4 clean-context generator branches (default 3, hard cap 4). Each branch receives the SAME Scope + Pattern context but a DIFFERENT assigned perspective, producing a full candidate draft spec:

• one conservative (low-risk, proven)
• one pattern-leveraging (maximize reuse of existing conventions)
• one innovative (novel approach)
• optionally one risk-minimizing (blast-radius-first)

Perspective diversity is deliberate, not naive N-identical sampling — quality dominates raw diversity, so cap at 3-4 high-quality branches, never spawn N clones (R3-04, R3-06; cost-ceiling C1 max 5 → capped at 4 here because spec generation is expensive). Use clean-context subagents so branches cannot self-condition on each other's trajectory (R1-03).

2. EVALUATE (bias-hardened scoring)

A single evaluator scores each candidate on the existing 7-dimension Explore rubric (Alignment 25% + Correctness 20% + Maintainability 15% + Performance 15% + Simplicity 10% + Risk 10% + Innovation 5% — see templates/scoring.md), applying EXPLICIT LLM-as-judge bias mitigations (R3-09):

• Strip authoring-branch identity/label from each candidate before scoring (counters self-preference / identity bias).
• Randomize / rotate candidate presentation order across the comparison (counters position bias).
• Length-normalize — judge on rubric-dimension content, not verbosity (counters verbosity bias).
• Anchor on deterministic checks — prefer the structural / dependency / constraint layers already in the Test (T) phase as the trust anchor over pure LLM judgment.

Record the per-candidate scores and the bias mitigations applied, so the evaluation is auditable in the final spec.

3. JUDGE-MERGE (mandatory aggregation)

Synthesize ONE spec by taking the highest-scoring approach per dimension:

• Record which candidate won each dimension and why, via [DECISION] markers (per-dimension provenance table).
• Carry every rejected candidate's rationale into the Rejected Alternatives section (SPEC.md E-phase step 6) — never silently discard a losing branch.

The result is one synthesized dual-format spec (Markdown + YAML/JSON) — downstream APIVR-Δ sees exactly one spec + one ECL envelope, identical to the standard cycle. The parallel mode is invisible at the hand-off boundary.

4. TERMINATE (bounded)

Stop when the merged-spec confidence ≥85% (Assemble gate) OR the iteration count reaches the hard cap of 3 — whichever comes first. The cap is inviolable (D5; the nexus trance-matrix R4 refusal gate). On non-convergence, emit a [GAP]/[BLOCKED] gap report and escalate to the human — do not loop past the cap.

Hard constraints (P0)

1. TRANCE-only — never the default; standard tier runs the single-pass cycle.
2. READ-ONLY; no worktree isolation needed (read-only ⇒ safe parallel).
3. Cap branches at 4 (default 3); cap iterations at 3.
4. Evaluator MUST apply identity-strip + order-rotate + length-normalize + deterministic-anchor and record them auditably.
5. JUDGE-MERGE produces ONE spec with per-dimension [DECISION] provenance.
6. Non-convergence → [GAP] escalation, never an unbounded loop.

See SPEC.md "## Parallel Spec Mode (TRANCE — G3 evaluator-optimizer)" for the full methodology section and DESIGN-RATIONALE.md DR-11 for the research basis.

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SPECTRA — Parallel Spec Mode (TRANCE / G3)