Context Store Interface: Protocol Binding Specification

Context Store Abstraction

The ECM Protocol defines a standard interface for context stores, enabling AI applications to work with different storage backends through a consistent API. This specification covers the protocol binding requirements.

Required Interface Methods

Storage Operations

Compliant stores must implement core operations:

interface ContextStore {
  put(context: Context): Promise<ContextRef>;
  get(id: ContextId): Promise<Context | null>;
  update(id: ContextId, context: Context): Promise<ContextRef>;
  delete(id: ContextId): Promise<void>;
  query(filter: ContextFilter): Promise<Context[]>;
}

Concurrency Control

Stores must support optimistic concurrency. ETags or version numbers for conflict detection. Conditional operations support (If-Match, If-None-Match). Clear error semantics for conflicts (HTTP 409 or equivalent).

Transactional Support

Optional transaction support for multi-context operations. Begin/commit/rollback semantics. Isolation level specifications. Timeout and cleanup for abandoned transactions.

Query Language Binding

Filter Expression Syntax

ECM Query Language (ECM-QL) provides portable queries:

{
  "filter": {
    "and": [
      {"field": "type", "op": "eq", "value": "user-context"},
      {"field": "metadata.region", "op": "in", "value": ["us-east", "us-west"]},
      {"field": "updated_at", "op": "gte", "value": "2024-01-01T00:00:00Z"}
    ]
  },
  "projection": ["id", "data.preferences"],
  "sort": [{"field": "updated_at", "order": "desc"}],
  "limit": 100,
  "offset": 0
}

Supported Operators

Standard comparison operators: eq (equals), ne (not equals), gt/gte/lt/lte (comparisons), in (set membership), contains (substring), exists (field presence).

Event Emission

Change Events

Stores should emit events for context changes. Event types: context.created, context.updated, context.deleted. Events carry sufficient detail for consumers to react. At-least-once delivery semantics.

Event Format

{
  "event_type": "context.updated",
  "context_id": "string",
  "context_type": "string",
  "timestamp": "ISO-8601",
  "changes": {
    "fields": ["data.preferences.theme"]
  }
}

Error Handling

Standardized error responses:

NOT_FOUND: Context ID does not exist
CONFLICT: Optimistic concurrency violation
VALIDATION_ERROR: Invalid context data
QUOTA_EXCEEDED: Storage limits reached
UNAUTHORIZED: Invalid or missing credentials
FORBIDDEN: Insufficient permissions

Conclusion

The Context Store Interface specification ensures interoperability between ECM Protocol clients and storage backends. Implementations must support core operations and event emission for full compliance.

> Context Store Interface: Protocol Binding Specification