Check Impact

Key rule: Changes to Stage N affect ALL stages N+1 through 8.

Workflow

Step 1: Identify What's Changing

Ask: "What entity/file/module is changing?" if not clear from context.

Map the change to a pipeline stage (or "non-pipeline" if it doesn't touch the DAG).

Step 2: Trace Downstream (ONE Explore subagent)

Launch ONE Explore subagent (haiku model). Search everything in a single pass — never spawn multiple subagents:

1. DB Impact — FK references, CASCADE rules on the changed entity
2. Service Impact — service methods consuming data from this module
3. Frontend Impact — React components displaying this data
4. Pipeline Impact — trace DAG: all stages from N+1 to 8 affected

Step 3: Tenant Scope Check

Determine if this change affects:

• All tenants (schema change, shared logic)
• Specific tenants (tenant-config-gated feature, specific exam type)
• No tenant impact (internal refactor)

Step 4: Generate Impact Report

IMPACT REPORT: [Change Description]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Pipeline Stage: [N] — [Stage Name]
Downstream Stages Affected: [N+1] through [8]

DB Impact:
  - [table] — [FK/CASCADE relationship]
  - [table] — [affected by JOIN]

Service Impact:
  - [service.method()] — [what it does with this data]
  - [service.method()] — [what it does]

Frontend Impact:
  - [component] — [what it displays]

Tenant Scope: [All / Specific / None]

CRITICAL SCENARIOS:
  ⚠ What if moderation already ran and this re-runs it?
  ⚠ What if grades are published and this changes retroactively?
  ⚠ What if GPA is calculated and formula changes?

RECOMMENDATION:
  [Safe to proceed / Needs migration plan / Needs staging test first]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Step 5: Special Scenarios (Exam Pipeline Only)

Always check these if pipeline stages are affected:

• What if moderation already ran and this re-runs it?
• What if grafting ran but the formula changes?
• What if GPA is published and calc method changes retroactively?
• What if results are on the portal and marks change?
• Revaluation flow: does this change break re-evaluation?

Red Flags - STOP

• "This only affects one table" — Check FKs. CampX entities are deeply connected.
• "No downstream impact" — Verify by actually searching, don't assume.
• "We can fix it after deploy" — If it touches published results, you can't.

All of these mean: STOP and verify before claiming safe.

Integration

• Called by: user directly (auto-triggered on "blast radius", "what breaks")
• Calls: Explore subagents (haiku, 4 parallel)
• Pairs with: explore-schema (for deeper entity relationship mapping)