# Governance Models Spec

**Status:** Draft
**Author:** Jordan Washburn
**Date:** 2026-02-05

---

## Problem

Episteme's append-only model means assertions are never deleted or mutated. Corrections happen via **supersession** — a signed record that marks an old assertion as replaced by a new one.

The current supersession model has no ownership enforcement: anyone with a valid signing key can supersede any assertion. The system records WHO did it (agent_id + signature) but doesn't restrict WHO is allowed.

This creates a tension between three legitimate use cases:

1. **Enterprise oversight:** IT must be able to correct a bot's mistake at 3am without waiting for the bot's owner.
2. **Personal ownership:** Researchers want their assertions to represent THEIR epistemic position — if you disagree, create a contradicting assertion, don't overwrite mine.
3. **Collaborative commons:** Wikipedia-style shared stewardship where anyone can edit, disputes are visible, and stewards handle escalation.

These are fundamentally different trust topologies, not just configuration options.

---

## Design

### Governance Model Enum

A cluster declares its governance model at configuration time. This is a cluster-level setting, not per-assertion or per-write.

```rust
/// Cluster governance model for supersession enforcement.
///
/// Determines who can supersede assertions and how disputes are resolved.
/// Set at cluster configuration time; affects all supersession operations.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub enum GovernanceModel {
    /// Anyone with a valid signature can supersede any assertion.
    ///
    /// Use case: Enterprise deployments where administrators need oversight
    /// capability. Incident response, compliance corrections, adversarial cleanup.
    ///
    /// Mental model: "IT can fix the bot's mistakes."
    Enterprise,

    /// Only the original assertion's signer can supersede it.
    ///
    /// Use case: Research, personal knowledge bases, contexts where authorship
    /// and epistemic ownership matter.
    ///
    /// Mental model: "My assertions are MY position. Disagree? Create your own."
    Sovereign,

    /// Anyone can supersede, but protection levels and stewards exist.
    ///
    /// Use case: Collaborative knowledge commons, Wikipedia-style editing where
    /// disputes are visible and stewards handle escalation.
    ///
    /// Mental model: "The commons owns everything. We track who did what."
    Commons {
        /// Public keys of steward agents who can override protection levels.
        stewards: Vec<[u8; 32]>,
        /// Default protection level for new assertions.
        default_protection: ProtectionLevel,
    },
}
```

### Protection Levels (Commons Mode Only)

In Commons mode, individual assertions can have protection levels that restrict who can supersede them.

```rust
/// Protection level for assertions in Commons governance mode.
///
/// Determines who can supersede a protected assertion. Only meaningful
/// when the cluster is running in Commons governance mode.
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
pub enum ProtectionLevel {
    /// Anyone can supersede (Wikipedia default).
    #[default]
    Open,

    /// Only agents with TrustRank >= threshold can supersede.
    /// Analogous to Wikipedia's "semi-protected" (blocks anonymous/new users).
    SemiProtected {
        min_trust_rank: f32,
    },

    /// Only stewards can supersede.
    /// Analogous to Wikipedia's "fully protected."
    FullyProtected,

    /// Only the original author can supersede.
    /// Same behavior as Sovereign mode, but per-assertion.
    AuthorOnly,
}
```

---

## Governance Model Comparison

| Aspect | Enterprise | Sovereign | Commons |
|--------|------------|-----------|---------|
| **Who can supersede?** | Anyone with valid signature | Only original signer | Depends on protection level |
| **Dispute resolution** | Top-down (admin decides) | No disputes (author owns) | Visible conflict + steward escalation |
| **Mental model** | Corporate wiki | Personal blog / academic paper | Wikipedia |
| **Trust topology** | Hierarchical | Individual | Federated |
| **Key failure mode** | Admin rewrites history | Orphaned assertions (lost keys) | Edit wars |
| **Escape hatch** | N/A (admins are the escape) | Quarantine (legal/safety) | Steward override |

---

## Real-World Analogues

### Enterprise → Corporate Wiki / Internal Docs

- Someone is accountable for the corpus
- Supervisors can correct subordinates' mistakes
- Incident response requires immediate correction capability
- Failure mode: "bad data persists because original agent is offline"

### Sovereign → Academic Papers / Personal Blog

- Authorship matters for citations and credit
- "I said X" is distinct from "we believe X"
- Corrections should come from the author (retractions)
- If you disagree, publish your own contradicting claim
- Failure mode: "I can never correct my old assertions if I lose my key"

### Commons → Wikipedia / OpenStreetMap

- Shared resource, not individual expression
- Anyone can edit, anyone can revert
- Disputes are visible in the history
- Stewards (admins) handle escalation and protection
- Failure mode: "edit wars" where users keep reverting each other

---

## Authorization Logic

```rust
impl GovernanceModel {
    /// Check if a supersession is authorized.
    ///
    /// # Arguments
    /// * `original_signer` - Public key of the assertion's primary signer
    /// * `superseding_agent` - Public key of the agent creating the supersession
    /// * `agent_trust_rank` - TrustRank of the superseding agent (0.0 to 1.0)
    /// * `assertion_protection` - Protection level of the target assertion
    ///
    /// # Returns
    /// `true` if the supersession is allowed, `false` otherwise.
    pub fn can_supersede(
        &self,
        original_signer: &[u8; 32],
        superseding_agent: &[u8; 32],
        agent_trust_rank: f32,
        assertion_protection: ProtectionLevel,
    ) -> bool {
        match self {
            // Enterprise: always allowed
            GovernanceModel::Enterprise => true,

            // Sovereign: owner only
            GovernanceModel::Sovereign => original_signer == superseding_agent,

            // Commons: depends on protection level
            GovernanceModel::Commons { stewards, default_protection } => {
                // Use assertion's protection or cluster default
                let protection = if assertion_protection == ProtectionLevel::default() {
                    *default_protection
                } else {
                    assertion_protection
                };

                match protection {
                    ProtectionLevel::Open => true,

                    ProtectionLevel::SemiProtected { min_trust_rank } => {
                        agent_trust_rank >= min_trust_rank
                    }

                    ProtectionLevel::FullyProtected => {
                        stewards.contains(superseding_agent)
                    }

                    ProtectionLevel::AuthorOnly => {
                        original_signer == superseding_agent
                    }
                }
            }
        }
    }
}
```

---

## Enforcement Point

Governance enforcement happens in the **ingestion worker**, not the API layer.

**Why ingestion worker?**
- All writes flow through the WAL → Ingestion pipeline
- Gossip-replicated supersessions bypass the API but hit the ingestor
- Single enforcement point prevents bypass
- Validation happens during batch processing, not query hot path

**Why NOT API layer?**
- Only protects direct HTTP writes
- Gossip-replicated supersessions would bypass enforcement

**Why NOT storage layer?**
- Too late — data already committed to WAL
- Rejection would require rollback logic

```rust
// In stemedb-ingest/src/worker/processing.rs

async fn ingest_supersession(&self, data: &[u8]) -> Result<()> {
    let supersession: Supersession = deserialize(data)?;

    // Fetch original assertion to get primary signer
    let original = self.fetch_assertion(&supersession.target_hash).await?;
    let original_signer = original.signatures.first()
        .ok_or(IngestError::InvalidSignature("No signatures"))?
        .agent_id;

    // Get superseding agent's trust rank (for Commons mode)
    let trust_rank = self.get_trust_rank(&supersession.agent_id).await?;

    // Get assertion's protection level (for Commons mode)
    let protection = original.protection.unwrap_or_default();

    // Check authorization
    if !self.governance.can_supersede(
        &original_signer,
        &supersession.agent_id,
        trust_rank,
        protection,
    ) {
        return Err(IngestError::Unauthorized(format!(
            "Agent {:?} cannot supersede assertion owned by {:?}",
            supersession.agent_id, original_signer
        )));
    }

    // Proceed with storage...
}
```

---

## Multi-Signature Assertions

Assertions can have multiple signatures (author + endorsers). For ownership purposes:

**Rule:** The first signature is the "primary signer" (assertion creator). Only the primary signer is considered the "owner" for Sovereign mode and AuthorOnly protection.

```rust
/// Get the primary signer (owner) of an assertion.
///
/// The primary signer is the first signature in the signatures array.
/// This represents the assertion creator; additional signatures are endorsers.
fn get_primary_signer(assertion: &Assertion) -> Option<[u8; 32]> {
    assertion.signatures.first().map(|s| s.agent_id)
}
```

**Rationale:**
- Deterministic: ordering defines ownership
- Matches mental model of "author + reviewers"
- Simple to implement

**Future extension:** If co-ownership is needed, add explicit `owners: Vec<[u8; 32]>` field to Assertion.

---

## Escape Hatches

### Sovereign Mode: Quarantine (Not Supersession)

In Sovereign mode, the owner exclusively controls supersession. But legal/safety situations require intervention. The solution: **quarantine** is distinct from supersession.

```rust
/// A quarantine record for assertions that cannot be superseded but must be hidden.
///
/// Quarantine is NOT supersession. The semantic difference:
/// - Supersession says: "I was wrong, here's the correction"
/// - Quarantine says: "This is being suppressed for external reasons"
///
/// The original assertion remains in the DAG. Quarantine affects query-time
/// filtering, not the underlying data.
pub struct Quarantine {
    /// Hash of the assertion being quarantined.
    pub target_hash: Hash,
    /// Why this assertion is quarantined.
    pub reason: QuarantineReason,
    /// Who issued the quarantine.
    pub authority: QuarantineAuthority,
    /// When the quarantine was issued.
    pub timestamp: u64,
    /// Whether the quarantine can be appealed/reversed.
    pub reversible: bool,
    /// Signature of the quarantine authority.
    pub signature: [u8; 64],
}

/// Reasons for quarantine (not error correction).
pub enum QuarantineReason {
    /// Court order or legal demand.
    LegalTakedown { order_id: String, jurisdiction: String },
    /// Violates safety policy.
    SafetyViolation { policy_version: String },
    /// Copyright claim (DMCA or equivalent).
    CopyrightClaim { claimant: String, dmca_id: Option<String> },
    /// Suspected compromised key.
    CompromisedKey { detection_method: String },
}

/// Who can issue a quarantine.
pub enum QuarantineAuthority {
    /// Cluster operator (legal/safety).
    Operator { operator_id: [u8; 32] },
    /// Automated system (flood detection, anomaly detection).
    Automated { system_name: String },
}
```

**Key distinction:**
- Supersession = "I was wrong" (epistemic correction)
- Quarantine = "This is hidden for external reasons" (administrative action)

Lenses respect quarantine by default but can include quarantined assertions with `include_quarantined: true` for auditors/researchers.

### Commons Mode: Steward Override

Stewards can supersede any assertion regardless of protection level. This is the escalation path for edit wars and disputes.

Steward actions are logged and auditable:

```rust
tracing::info!(
    target_hash = %hex::encode(supersession.target_hash),
    steward = %hex::encode(supersession.agent_id),
    reason = %supersession.reason,
    "Steward override supersession"
);
```

---

## Attack Vectors and Mitigations

### Owner-Only Creates "Immutable Misinformation"

**Attack:** Flood assertions with malicious content, then discard the signing key. Assertions are now uncorrectable.

**Mitigation:** Quarantine mechanism allows hiding without superseding. Flood detection + auto-quarantine for anomalous behavior.

```rust
/// Detect suspicious assertion patterns.
struct FloodDetector {
    /// Track assertion rate per key
    rate_limiter: HashMap<[u8; 32], TokenBucket>,
    /// Threshold for auto-quarantine (assertions per minute)
    threshold: u32,
}

impl FloodDetector {
    fn is_flood(&self, agent_id: &[u8; 32]) -> bool {
        self.rate_limiter.get(agent_id)
            .map(|bucket| bucket.rate() > self.threshold)
            .unwrap_or(false)
    }
}
```

### Key Loss = Lost Ownership

**Attack:** User loses private key, can never correct old assertions.

**Mitigation:** Accept this as a feature, not a bug. Key security matters. Users can re-assert with a new key (creates duplicate in DAG), and lenses will resolve based on recency/trust.

```rust
/// Re-assert old claims with a new key after key loss.
///
/// This creates a new assertion with the same content but different signer.
/// The old assertion remains (append-only). Lenses see both and resolve
/// based on recency, trust, or other criteria.
async fn re_assert_with_new_key(
    old_assertion_id: Hash,
    new_signer: &Keypair,
    db: &StemeDB,
) -> Result<Hash> {
    let old = db.get_assertion(&old_assertion_id).await?;

    let new_assertion = Assertion {
        subject: old.subject.clone(),
        predicate: old.predicate.clone(),
        object: old.object.clone(),
        // ... new signer, new timestamp
    };

    db.ingest(new_assertion, new_signer).await
}
```

### Key Compromise

**Attack:** Attacker steals key, posts false assertions, user rotates key but old false assertions persist.

**Mitigation:** Quarantine all recent assertions from suspected compromised key.

```rust
/// Quarantine all assertions from a suspected compromised key.
async fn quarantine_compromised_key(
    key: &[u8; 32],
    since: DateTime<Utc>,
    db: &StemeDB,
) -> Result<u64> {
    let assertions = db.get_assertions_by_signer(key, since).await?;

    let mut count = 0;
    for assertion in assertions {
        db.quarantine(&assertion.hash, QuarantineReason::CompromisedKey {
            detection_method: "user_reported".to_string(),
        }).await?;
        count += 1;
    }

    tracing::warn!(
        key = %hex::encode(key),
        quarantined_count = count,
        "Quarantined assertions from suspected compromised key"
    );

    Ok(count)
}
```

---

## Configuration

### Cluster Config

```rust
pub struct ClusterConfig {
    // ... existing fields ...

    /// Governance model for supersession enforcement.
    /// Default: Enterprise (backward compatible with current behavior).
    pub governance: GovernanceModel,
}
```

### TOML Examples

**Enterprise deployment:**

```toml
[cluster]
governance = "enterprise"
```

**Personal research instance:**

```toml
[cluster]
governance = "sovereign"
```

**Public knowledge commons:**

```toml
[cluster.governance]
type = "commons"
default_protection = "open"

[[cluster.governance.stewards]]
key = "abc123..." # hex-encoded public key

[[cluster.governance.stewards]]
key = "def456..."
```

---

## Distributed Replication Considerations

### Out-of-Order Delivery

**Problem:** Node A receives supersession before the target assertion (gossip timing).

**Solution:** Deferred validation with quarantine buffer.

```rust
async fn ingest_supersession(&self, data: &[u8]) -> Result<()> {
    let supersession: Supersession = deserialize(data)?;

    // Check if target exists locally
    match self.fetch_assertion(&supersession.target_hash).await {
        Ok(original) => {
            // Target exists, validate ownership
            self.validate_and_store(supersession, original).await
        }
        Err(NotFound) => {
            // Target not here yet, quarantine for later
            tracing::warn!(
                target = %hex::encode(supersession.target_hash),
                "Supersession before target, quarantining"
            );
            self.quarantine_pending_supersession(supersession).await
        }
    }
}
```

Quarantined supersessions are re-evaluated when new assertions arrive (anti-entropy sweep).

### Cluster-Wide Consistency

All nodes in a cluster must use the same governance model. Enforcement happens at each node's ingestion worker, so:

- If target arrives first → validation succeeds immediately
- If supersession arrives first → quarantined until target arrives
- Both cases converge to the same final state

---

## API Changes

### New Endpoints

```
POST   /v1/quarantine              Create a quarantine record (operator only)
GET    /v1/quarantine/{hash}       Get quarantine status for an assertion
DELETE /v1/quarantine/{hash}       Remove quarantine (if reversible)
GET    /v1/governance              Get cluster governance model
```

### Query Params

```rust
pub struct QueryParams {
    // ... existing fields ...

    /// Include quarantined assertions in results.
    /// Default: false (quarantined assertions are hidden).
    pub include_quarantined: Option<bool>,
}
```

### Supersede Request Validation

The existing `/v1/supersede` endpoint gains governance validation:

```rust
// In supersede handler
if !state.governance.can_supersede(...) {
    return Err(ApiError::Forbidden(
        "Supersession not authorized by governance model".to_string()
    ));
}
```

---

## Migration Path

### Phase 1: Add Types (No Enforcement)

- Add `GovernanceModel`, `ProtectionLevel`, `Quarantine` types to `stemedb-core`
- Add `governance` field to `ClusterConfig`
- Default to `Enterprise` (backward compatible)
- No enforcement yet

### Phase 2: Sovereign Enforcement

- Add ownership check in ingestion worker
- When `governance == Sovereign`, reject non-owner supersessions
- Add quarantine store and basic quarantine API

### Phase 3: Commons Enforcement

- Add `protection` field to Assertion
- Add steward check logic
- Add protection level management API
- Add conflict detection lens (surfaces "edit wars")

### Phase 4: Safety Features

- Flood detection + auto-quarantine
- Compromised key quarantine workflow
- Quarantine appeal/reversal API

---

## Design Decisions

1. **Cluster-level, not per-assertion governance.** Governance model is a fundamental trust topology, not a per-write decision. Mixing models would create confusion and split-brain scenarios in distributed replication.

2. **First signature is owner.** Simple, deterministic. Co-ownership can be added later if needed.

3. **Quarantine ≠ Supersession.** Semantically distinct operations. Supersession is epistemic ("I was wrong"). Quarantine is administrative ("hidden for external reasons"). Both needed.

4. **Accept key loss = lost ownership.** Feature, not bug. Encourages key security. Re-assertion with new key is the recovery path.

5. **Stewards, not admins.** In Commons mode, the term "steward" emphasizes service to the community, not authority over it. Matches Wikipedia terminology.

6. **No per-assertion governance override.** An assertion in a Sovereign cluster can't opt into Commons behavior. The governance model is a property of the cluster, not the data.

---

## Relationship to Other Specs

- **Supersession:** This spec defines WHO can supersede. The existing supersession spec defines WHAT supersession means (Invalidate, Temporal, Refinement, etc.).

- **Concept Hierarchy:** Governance is orthogonal to concept paths. A Commons cluster could have hierarchical concept paths; a Sovereign cluster could have flat subjects.

- **Epochs:** Epoch supersession follows the same governance rules. In Sovereign mode, only the epoch creator can supersede it.

- **TrustRank:** Used by SemiProtected protection level. Low-trust agents can't supersede semi-protected assertions.

---

## What We Do NOT Build

- No voting/consensus mechanism for governance changes (cluster config is operator-controlled)
- No delegation chains in v1 (can be added later)
- No per-assertion governance override
- No governance transitions while cluster is running (requires restart)
- No cross-cluster governance federation (each cluster has its own model)
- No UI for governance management (API + config only)