Task Complexity Routing (SNC)
Priority: P1 (HIGH)
Same ticket label, different engineering difficulty. Score the task, not the label, then route by tier.
Score
| Dimension | 0 | 1 | 2 |
|---|---|---|---|
| Spread (how far the change reaches) | one file, one module | several files, one module | cross-module or cross-service |
| Novelty (new vs existing behavior) | small edit or removal of existing behavior | modify existing logic | new behavior or rewrite |
| Centrality (how core the touched code is) | peripheral code | shared but non-core | core domain, hot path, auth, money, trust boundary |
Sum the three, never average. Output line: SNC: S=[0-2] N=[0-2] C=[0-2] total=[n] tier=[low|medium|high].
Tiers
tier=low: total 0-2tier=medium: total 3-4tier=high: total 5-6
Routing
| Tier | Autonomy | Verification | Review | Approval | model_tier |
|---|---|---|---|---|---|
tier=low | autonomous | basic: focused tests + lint | fast code-review | none required | fast |
tier=medium | guided | TDD + self-review | deep code-review | plan reviewed, no HARD STOP | standard |
tier=high | plan-first | TDD + independent reviewers (specialist-architecture-guard, specialist-security-reviewer when relevant) | deep code-review | HARD STOP before code, human approval before merge | strong |
Sensitive-Change Risk Floor
Sensitive changes touching authentication, authorization, payments/financial data, data integrity, secrets, or system trust boundaries have an explicit risk floor independent of arithmetic SNC totals:
- Floor: Minimum
tier=medium(guided execution, deep review, human plan acknowledgment) even if arithmetic total is ≤2 (e.g. S=0, N=0, C=2). - High Sensitivity: If spread or novelty is non-zero (S≥1 or N≥1 with C=2), enforce
tier=high(plan-first HARD STOP, independent security review, human merge approval). - Irreversible Actions: Actions involving data destruction, schema drops, credential rotation, privilege escalation, or production cutover strictly require explicit human authorization regardless of tier.
Rules
- Score before planning; emit
snc_tierandmodel_tierin every Handoff Payload. - Label the score as inference when derived from ticket text alone; re-score after
specialist-codebase-scoutreports impact radius. - Round up on doubt. Any auth, money, trust-boundary, or hot-path touch is C=2 and subject to the sensitive-change risk floor.
- Downward complexity reassessment is permitted ONLY with documented new evidence (e.g., scouted blast radius proves isolated scope with verified non-interference), NEVER to bypass unresolved risk, required approvals, or the sensitive-change risk floor.
- Re-score when scope grows mid-task; the tier must rise immediately when expansion is detected.
- Never downgrade a tier to skip a gate. Ticket type (bug vs feature) never sets the tier.
Red Flags
Stop and re-score when hearing or thinking: "it's just a bug fix", "one-line change", "skip the plan, it's small", "we'll review it later", "mark it low so we can merge tonight". Each is a rationalization, not a score.
Anti-Patterns
- No tier by ticket type: "bug" and "feature" say nothing about S, N, or C.
- No averaging: three 1s and one 2/0/1 both route differently only when summed.
- No silent tier: a plan or handoff without
snc_tieris incomplete. - No high tier without named reviewers:
tier=highmust list which specialists review before merge.
