[Feature]: Collaborative Memory with Dynamic Access Controls (ACLs)

[zircote]

Problem Statement

Current Subcog scoping (project/user/org) is static and does not support:

• Fine-grained sharing of specific memories between users
• Time-evolving access permissions
• Selective memory visibility based on roles
• Compliance requirements for data access auditing

Enterprise deployments need memory sharing with proper access controls, especially in regulated industries (healthcare, finance) where data access must be auditable.

Proposed Solution

Implement collaborative memory with dynamic access controls:

1. Memory Fragments: Each memory can have individual access rules
2. Bipartite Access Graph: Links users, agents, and resources
3. Two Memory Tiers:
   • Private memory: Visible only to originating user
   • Shared memory: Selectively shared fragments
4. Immutable Provenance: Contributing agents, accessed resources, timestamps

Features:

• Share specific memories with specific users/teams
• Time-bounded access (expires after date)
• Role-based access patterns (viewer, editor, admin)
• Retrospective permission checks via provenance

Proposed API:

pub struct MemoryAcl {
    memory_id: MemoryId,
    owner: UserId,
    permissions: Vec<Permission>,
}

pub struct Permission {
    grantee: Grantee,           // User, Team, or Role
    access_level: AccessLevel,   // Read, Write, Admin
    valid_from: DateTime,
    valid_until: Option<DateTime>,
}

MCP tools:

subcog_share:
  memory_id: "abc123"
  with: ["user:alice", "team:backend"]
  access: "read"
  expires: "30d"

subcog_permissions:
  memory_id: "abc123"
  action: list  # or: grant, revoke, audit

Alternatives Considered

• Namespace-level sharing only (too coarse-grained)
• External IAM integration only (loses memory-specific semantics)
• Copy-on-share model (loses single source of truth)

Additional Context

• Research: https://arxiv.org/abs/2505.18279
• Extends current org domain with fine-grained controls
• Essential for enterprise/compliance use cases

Breaking Change: Yes - minor changes (ACL fields on memories)
Priority: Critical
Contribution: Yes, with guidance