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+# Mutual Bond System Design
+
+## Problem
+
+Partnership is currently a one-sided label derived from sentiment value. NPC A can call B their partner while B considers C their partner. The `classify()` function maps value >= 80 to "Partner" independently per entity, with no mutuality enforcement.
+
+## Solution
+
+Separate feelings from formal relationship status via three changes:
+
+### 1. Bond Registry
+
+World-level singleton component: `BondRegistry = Map<pairKey, Bond[]>`
+
+```typescript
+interface Bond {
+  type: 'partner';              // extensible: 'sibling', 'parent', etc.
+  formedAtTick: number;
+  status: 'active' | 'former';
+}
+```
+
+- Keyed by canonical pair key (`"lowerEntityId:higherEntityId"`)
+- Helper functions: `makePairKey()`, `getBonds()`, `hasBond()`, `addBond()`, `dissolveBond()`
+- When a partner despawns, bond transitions to `status: 'former'` (consistent with existing memory system)
+- Single source of truth for all structural relationships
+
+### 2. Proposal Interaction
+
+General-purpose mutual agreement protocol, with partnership as the first use case.
+
+**New fields on `SocialState`:**
+- `proposalCooldown: number` -- ticks until this entity can propose again
+- `pendingProposal: { targetId: EntityId, type: 'partner' } | null` -- queued by relationship system
+
+**Flow:**
+
+1. **RelationshipSystem** (after updating sentiment): if entity's value toward other crosses >= `proposalThreshold` (default 80), no existing bond, no proposal cooldown, sets `pendingProposal` on the entity
+2. **SocialSystem** (new interaction detection): when scanning for partners, if entity has `pendingProposal` targeting a nearby NPC, prioritize initiating interaction with that target. Interaction is flagged as proposal type.
+3. **Proposal phases**: reuses existing `facing -> pausing -> emoting` but emoting phase uses ring emoji
+4. **Resolution** (emoting->done transition):
+   - Check rejecter's sentiment toward proposer (must be >= `proposalAcceptanceThreshold`)
+   - Stat-influenced acceptance roll: base ~85%, empathy (+), sociability (+), temperament (-)
+   - **Accept**: bond added to registry, sentiment boost, positive emote, positive transient mods
+   - **Reject**: proposer takes amplified negative delta (2x), rejecter takes smaller hit (0.5x), both scaled by temperament. Proposal cooldown set on initiator, reduced by courage.
+
+### 3. Classification Rework
+
+- `classify()`: rename >= 80 tier from `'Partner'` to `'Devoted'`
+- `getEffectiveClassification()`: add bond registry parameter. If `hasBond(partner, active)`, return `'Partner'` overriding the tier label
+- `stateSerializer.ts`: switch from `classify()` to `getEffectiveClassification()`, pass bond registry
+- Wire protocol: add `bond: 'partner' | 'former_partner' | null` field to serialized relationships
+
+### 4. Client Display
+
+- Ring emoji during proposal interaction (above both NPCs)
+- NPC info panel: ring icon next to partner names
+- Acceptance: ring emoji, then positive emote
+- Rejection: ring emoji transitions to negative emote
+
+### 5. Config Additions
+
+All tuning values in `relationshipConfig.ts`:
+
+```typescript
+// Proposal system
+proposalThreshold: 80,
+proposalAcceptanceThreshold: 80,
+proposalBaseAcceptanceChance: 0.85,
+proposalEmpathyWeight: 0.02,
+proposalSociabilityWeight: 0.02,
+proposalTemperamentWeight: -0.02,
+proposalAcceptanceBonus: 5,
+proposalRejectionMultiplier: 2.0,
+proposalRejectionRejecterMultiplier: 0.5,
+baseProposalCooldown: 500,
+courageCooldownWeight: 0.04,
+proposalAcceptanceSociabilityMod: 2,
+proposalAcceptanceEmpathyMod: 1,
+proposalRejectionSociabilityMod: -1,
+proposalRejectionEmpathyMod: -1,
+proposalModDecayTicks: 150,
+```
+
+## Key Properties
+
+- Feelings remain asymmetric and per-entity (existing system unchanged)
+- Formal relationships are symmetric and centrally stored
+- System is general enough for future bond types (sibling, parent/child)
+- All tuning values configurable
+- Rejection has real consequences, creating emergent drama
+- System execution order unchanged: social -> relationship