Hollow

v1.3.0 — Agent Lineage and Call Graphs

The audit log records what happened. Lineage records why — who called who, which task spawned which agent, which transaction touched which resource. This is the distributed tracing layer.

New: agents/lineage.py

• LineageGraph — persisted directed graph of agent relationships
• record_edge(parent_id, child_id, edge_type, metadata) — edge types: spawned, delegated, signaled, transacted
• get_lineage(agent_id) — full ancestor chain to root
• get_subtree(root_id) — recursive descendant call tree with edge metadata
• get_blast_radius(agent_id) — forward-reachability: affected agents, locked resources, open transactions, running tasks
• critical_path(task_id) — longest depends_on chain (minimum wall time for a workflow)
• Persisted to lineage.json

Changes to existing code

• AgentRecord gains parent_task_id
• AuditEntry gains caused_by_task_id, parent_txn_id, call_depth
• Task gains depends_on: list, parent_task_id
• register() accepts parent_task_id and explicit parent_id override (admin only)
• submit() and spawn_agent() propagate parent_task_id and depends_on
• Lineage edges recorded automatically on every agent_register and agent_spawn

New API endpoints

• GET /agents/{id}/lineage — ancestor chain
• GET /agents/{id}/subtree — full descendant call graph
• GET /agents/{id}/blast-radius — forward-reachability impact analysis
• GET /tasks/{id}/critical-path — longest dependency chain

New MCP tools (64 → 68)

agent_lineage, agent_subtree, agent_blast_radius, task_critical_path

Integration tests

7 tests, all passing. No Ollama required.