# Provenance Timestamp Rules

**Created**: 2025-12-30
**Updated**: 2025-12-30
**Status**: Active Rule
**Related**: WEB_CLAIM_PROVENANCE_SCHEMA.md, YAML_PROVENANCE_SCHEMA.md, WEB_OBSERVATION_PROVENANCE_RULES.md

## Core Principle: Every Provenance Statement MUST Have At Least Two Timestamps

**All provenance statements in custodian data MUST include at minimum two timestamps:**

1. **`statement_created_at`** - When the provenance statement/claim was created (extraction/annotation time)
2. **`source_archived_at`** - When the source material was archived/captured

These two timestamps are MANDATORY. Additional temporal metadata is encouraged but optional.

---

## Mandatory Timestamps

### 1. Statement Created Timestamp (`statement_created_at`)

**Purpose**: Records when the claim/statement was extracted, annotated, or created by the agent.

**Format**: ISO 8601 with timezone (UTC preferred)

**Example**:
```yaml
statement_created_at: "2025-12-30T14:30:00Z"
```

**Source**: Generated by the extraction/annotation agent at processing time.

### 2. Source Archived Timestamp (`source_archived_at`)

**Purpose**: Records when the source material (webpage, document, API response) was archived/captured.

**Format**: ISO 8601 with timezone (UTC preferred)

**Example**:
```yaml
source_archived_at: "2025-12-29T10:15:00Z"
```

**Source**: 
- For web sources: Playwright archival timestamp, Wayback Machine memento datetime
- For API sources: API response fetch timestamp
- For documents: Document capture/download timestamp

---

## Optional Timestamps (Encouraged)

### 3. Source Created Timestamp (`source_created_at`)

**Purpose**: When the original source content was created/published.

**Example**:
```yaml
source_created_at: "2022-07-15T14:15:00Z"  # Article publish date
```

**Sources**:
- `article:published_time` meta tag
- `datePublished` in JSON-LD
- File creation date
- API response `created_at` field

### 4. Source Last Modified Timestamp (`source_last_modified_at`)

**Purpose**: When the source content was last updated.

**Example**:
```yaml
source_last_modified_at: "2023-01-10T09:00:00Z"
```

**Sources**:
- `article:modified_time` meta tag
- `dateModified` in JSON-LD
- HTTP `Last-Modified` header
- File modification date

### 5. Verification Timestamp (`last_verified_at`)

**Purpose**: When the claim was last re-verified against the source.

**Example**:
```yaml
last_verified_at: "2025-12-30T14:30:00Z"
```

### 6. Next Verification Due (`next_verification_due`)

**Purpose**: When the claim should be re-verified (for staleness tracking).

**Example**:
```yaml
next_verification_due: "2026-03-30T00:00:00Z"  # 90 days from last verification
```

---

## Complete Provenance Timestamp Structure

### For Web Claims

```yaml
provenance:
  # MANDATORY (both required)
  statement_created_at: "2025-12-30T14:30:00Z"   # When we extracted this
  source_archived_at: "2025-12-29T10:15:00Z"    # When we archived the webpage
  
  # OPTIONAL (encouraged)
  source_created_at: "2022-07-15T14:15:00Z"     # When article was published
  source_last_modified_at: "2023-01-10T09:00:00Z"  # When article was updated
  last_verified_at: "2025-12-30T14:30:00Z"      # Last verification
  next_verification_due: "2026-03-30T00:00:00Z" # Re-verify in 90 days
```

### For API-Sourced Data (Wikidata, Google Maps, etc.)

```yaml
_provenance:
  # MANDATORY
  statement_created_at: "2025-12-30T14:30:00Z"   # When we processed API response
  source_archived_at: "2025-12-30T14:29:55Z"    # When API was queried (fetch_timestamp)
  
  # OPTIONAL
  source_last_modified_at: "2025-12-15T00:00:00Z"  # Wikidata entity last modified
  last_verified_at: "2025-12-30T14:30:00Z"
```

### For CH-Annotator Extracted Claims

```yaml
provenance:
  namespace: glam
  path: /conversations/edc75d66-ee42-4199-8e22-65b0d2347922
  
  # MANDATORY
  statement_created_at: "2025-12-06T21:13:56Z"   # When CH-Annotator processed this
  source_archived_at: "2025-11-06T08:02:44Z"    # When conversation was exported
  
  # Agent identification
  agent: opencode-claude-sonnet-4
  context_convention: ch_annotator-v1_7_0
```

---

## Invalid Provenance: `agent: claude-conversation`

**PROBLEM**: 24,328 custodian files currently contain provenance statements like:

```yaml
# INVALID - Missing timestamps and proper source identification
extraction_provenance:
  namespace: glam
  path: /conversations/edc75d66-ee42-4199-8e22-65b0d2347922
  timestamp: '2025-11-06T08:02:44.240037+00:00'  # Only ONE timestamp!
  agent: claude-conversation  # Vague agent identifier
  context_convention: ch_annotator-v1_7_0
```

**ISSUES**:
1. `claude-conversation` is not a valid agent identifier (which Claude model? which session?)
2. Only one timestamp - doesn't distinguish statement creation from source archival
3. No UUID reference to the specific conversation
4. No archived source path

---

## Valid Provenance Structure (Migration Target)

```yaml
extraction_provenance:
  namespace: glam
  
  # Source identification
  source_type: claude_conversation_export
  source_path: /conversations/edc75d66-ee42-4199-8e22-65b0d2347922
  conversation_uuid: edc75d66-ee42-4199-8e22-65b0d2347922
  
  # MANDATORY timestamps
  statement_created_at: "2025-12-06T21:13:56.173868+00:00"  # Annotation time
  source_archived_at: "2025-11-06T08:02:44.240037+00:00"   # Conversation export time
  
  # Agent identification (proper format)
  agent:
    name: opencode-claude-sonnet-4
    model: claude-sonnet-4-20250514
    session_type: opencode_conversation
  
  # Context
  context_convention: ch_annotator-v1_7_0
  
  # Archive reference
  archive:
    format: claude_conversation_json
    local_path: data/conversations/edc75d66-ee42-4199-8e22-65b0d2347922.json
```

---

## Timestamp Hierarchy and Derivation

When only one timestamp is available, derive the other:

| Available | Derive `statement_created_at` | Derive `source_archived_at` |
|-----------|------------------------------|----------------------------|
| Only `timestamp` | Use as `statement_created_at` | Set to same value (assume simultaneous) |
| Only `extraction_date` | Use as `statement_created_at` | Set to same value |
| Only `fetch_timestamp` | Set to same value | Use as `source_archived_at` |
| Only `annotation_date` | Use as `statement_created_at` | Look for `timestamp` in source |

**Migration rule**: If we cannot determine `source_archived_at`, use the earliest available timestamp from the source chain.

---

## Agent Identification Standards

### Invalid Agent Identifiers

```yaml
# INVALID - Too vague
agent: claude-conversation
agent: claude
agent: ai
agent: llm
agent: opencode
```

### Valid Agent Identifiers

```yaml
# Format: {tool}-{model}-{version}
agent: opencode-claude-sonnet-4
agent: opencode-claude-opus-4
agent: batch-script-python-3.11
agent: manual-human-curator

# Or structured format
agent:
  name: opencode-claude-sonnet-4
  model: claude-sonnet-4-20250514
  tool: opencode
  version: "1.0.0"
```

---

## PROV-O Alignment

These timestamps align with W3C PROV-O:

| Our Field | PROV-O Property | Description |
|-----------|-----------------|-------------|
| `statement_created_at` | `prov:generatedAtTime` | When entity was generated |
| `source_archived_at` | `prov:atTime` (on Activity) | When archival activity occurred |
| `source_created_at` | `dcterms:created` | Original creation date |
| `source_last_modified_at` | `dcterms:modified` | Last modification date |

```yaml
prov:
  generatedAtTime: "2025-12-30T14:30:00Z"  # = statement_created_at
  wasGeneratedBy:
    "@type": "prov:Activity"
    name: "web_extraction"
    atTime: "2025-12-29T10:15:00Z"  # = source_archived_at
```

---

## Validation Rules

### Rule 1: Both Mandatory Timestamps Required

```python
def validate_provenance_timestamps(provenance: dict) -> list[str]:
    errors = []
    
    # Check for mandatory timestamps
    if 'statement_created_at' not in provenance:
        errors.append("Missing mandatory 'statement_created_at' timestamp")
    if 'source_archived_at' not in provenance:
        errors.append("Missing mandatory 'source_archived_at' timestamp")
    
    return errors
```

### Rule 2: Timestamps Must Be Valid ISO 8601

```python
from datetime import datetime

def validate_timestamp_format(timestamp: str) -> bool:
    try:
        datetime.fromisoformat(timestamp.replace('Z', '+00:00'))
        return True
    except ValueError:
        return False
```

### Rule 3: source_archived_at <= statement_created_at

The source must be archived BEFORE or AT the same time as the statement is created.

```python
def validate_timestamp_order(provenance: dict) -> bool:
    archived = datetime.fromisoformat(provenance['source_archived_at'])
    created = datetime.fromisoformat(provenance['statement_created_at'])
    return archived <= created
```

---

## Migration Strategy for Existing Files

### Phase 1: Identify Files Needing Migration

```bash
# Count affected files
find data/custodian -name "*.yaml" -exec grep -l "agent: claude-conversation" {} \; | wc -l
# Result: 24,328 files
```

### Phase 2: Parse and Transform

For each file with `agent: claude-conversation`:

1. Extract existing `timestamp` field
2. Set `source_archived_at` = existing `timestamp`
3. Set `statement_created_at` = `annotation_date` if present, else use current time
4. Replace `agent: claude-conversation` with proper agent identifier
5. Add conversation UUID from path

### Phase 3: Validate and Write

```python
def migrate_provenance(data: dict) -> dict:
    """Migrate old claude-conversation provenance to new format."""
    
    if 'ch_annotator' in data:
        ch = data['ch_annotator']
        
        if ch.get('extraction_provenance', {}).get('agent') == 'claude-conversation':
            old_prov = ch['extraction_provenance']
            
            # Extract conversation UUID from path
            path = old_prov.get('path', '')
            conv_uuid = path.split('/')[-1] if '/conversations/' in path else None
            
            # Get timestamps
            source_archived_at = old_prov.get('timestamp')
            statement_created_at = ch.get('annotation_provenance', {}).get('annotation_date', source_archived_at)
            
            # Build new provenance
            ch['extraction_provenance'] = {
                'namespace': old_prov.get('namespace', 'glam'),
                'source_type': 'claude_conversation_export',
                'source_path': old_prov.get('path'),
                'conversation_uuid': conv_uuid,
                'statement_created_at': statement_created_at,
                'source_archived_at': source_archived_at,
                'agent': 'opencode-claude-sonnet-4',  # Default migration value
                'context_convention': old_prov.get('context_convention'),
                'migration_note': 'Migrated from agent:claude-conversation on 2025-12-30'
            }
    
    return data
```

---

## Implementation Checklist

- [ ] Add `statement_created_at` to all new provenance statements
- [ ] Add `source_archived_at` to all new provenance statements
- [ ] Replace `agent: claude-conversation` with proper agent identifiers
- [ ] Add conversation UUIDs where applicable
- [ ] Migrate existing 24,328 files with invalid provenance
- [ ] Update LinkML schema to require dual timestamps
- [ ] Add validation to data pipeline

---

## Related Documentation

- `.opencode/WEB_CLAIM_PROVENANCE_SCHEMA.md` - Web claim provenance structure
- `.opencode/YAML_PROVENANCE_SCHEMA.md` - YAML enrichment provenance
- `.opencode/WEB_OBSERVATION_PROVENANCE_RULES.md` - XPath provenance requirements
- `AGENTS.md` - Rule 35: Provenance Timestamps