tester agent JSON schema validation always fails in stream-json mode #458

Summary

When using the conductor-bootstrap config (which triggers debug-workflow), the tester agent consistently fails with JSON schema validation errors even though the agent completes successfully and the underlying work is correct.

Error

Error: Agent tester output failed JSON schema validation:
  #/required must have required property 'approved'
  #/required must have required property 'summary'
  #/required must have required property 'commandResult'
  #/required must have required property 'rootCauseVerification'
  #/required must have required property 'testVerification'

Root Cause

The tester agent in debug-workflow.json runs with stream-json output format (for live log visibility). In this mode, zeroshot validates the structured_output field of the final stream-json result against the agent's output schema after the fact.

However, because --json-schema is silently ignored when outputFormat !== 'json' (see runner.js → resolveJsonSchema), Claude is never told about the required schema shape. Claude produces its standard stream-json structured_output with {"summary": "...", "result": "..."} instead of the schema-required fields (approved, commandResult, rootCauseVerification, testVerification).

The result: schema validation always fails for the tester agent, causing the cluster to reject valid work and retry indefinitely.

Evidence

From task log, Claude's structured_output:

{
  "summary": "Fix already applied in iteration 1; tester rejection was tester agent crash, not code issue",
  "result": "ROOT CAUSE FIX: ..."
}

The agent itself noted: "The previous rejection was due to the tester agent crashing with JSON schema validation errors — the code fix was correct and already applied."

Expected Behavior

Either:

1. The tester agent should use strictSchema: true in debug-workflow.json so --output-format json --json-schema <schema> is passed to Claude, enforcing the schema natively, or
2. When a jsonSchema is defined on an agent, the system prompt should inject the schema shape so Claude knows to produce it even in stream-json mode

Config Used

conductor-bootstrap (out of the box, no customization)