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Claude Code Callback

The most powerful evaluation mode : Claude Code acts as the supervisor's brain, with full codebase context.

Architecture

When evaluator.provider is claude-code, sup7 doubles as an MCP server exposing two tools :

  • sup7_pending — returns evaluations waiting for review
  • sup7_verdict — accepts a decision (action, confidence, reasoning)
Claude Code ──MCP──► flux7-mesh ──MCP──► sup7
                                          │
                     sup7_pending ◄───────┘  Claude Code pulls
                     sup7_verdict ────────►  Claude Code responds
                                          │
                     flux7-mesh ◄─────────┘  sup7 resolves

Flow

  1. An agent makes a tool call governed by flux7-mesh with human_approval policy
  2. sup7 picks up the pending approval
  3. Rules don't match → needs LLM evaluation
  4. Provider is claude-code → sup7 queues the evaluation
  5. Claude Code calls sup7_pending through flux7-mesh, sees the request with full context
  6. Claude Code evaluates — it can read files, check git history, review the agent's recent activity
  7. Claude Code calls sup7_verdict with its decision
  8. sup7 receives the verdict, resolves the original approval in flux7-mesh
  9. If timeout expires (default 120s) → escalate to human

Why MCP callback

Direct LLM call MCP callback
Context Tool name + params only Full codebase, git history, conversations
Judgment Pattern matching Semantic understanding
Blocking Synchronous Async — doesn't block other evaluations
Coupling Tied to specific API Any MCP-capable agent can evaluate

Claude Code has context that no API call can replicate. It knows what the user is working on, what files were recently changed, what the project structure looks like. A file write to src/main.py means something different during a refactor than during a security audit.

Configuration

sup7 config

evaluator:
  provider: claude-code
  callback_timeout: 120  # seconds to wait for verdict

mcp_server:
  enabled: true
  transport: stdio       # registered in flux7-mesh config

flux7-mesh config

Register sup7 as an MCP source so Claude Code can see its tools :

mcp_servers:
  - name: sup7
    command: sup7
    args: ["start", "--config", "sup7.yaml", "--mcp"]
    transport: stdio

Policy

Allow the supervisor agent to resolve approvals :

supervisor:
  enabled: true
  supervisor_agents: ["supervisor"]

MCP tools reference

sup7_pending

Returns a list of evaluations waiting for review.

Parameters : none

Response :

[
  {
    "id": "abc123",
    "agent_id": "claude-coder",
    "tool": "filesystem.write_file",
    "params": {"path": "/home/user/project/src/main.py", "content": "..."},
    "policy_rule": "writes-need-approval",
    "injection_risk": false,
    "recent_traces": [...],
    "active_grants": [...]
  }
]

sup7_verdict

Submit a decision for a pending evaluation.

Parameters :

Field Type Description
approval_id string The approval ID from sup7_pending
action string "approve", "deny", or "escalate"
confidence float 0.0–1.0 confidence score
reasoning string One sentence explanation

Response : "accepted" or error message.