Bug: Model Override in Cron Jobs Corrupts Parent Session State

Summary

When a cron job is configured with a model override (e.g., model: "ollama/kimi-k2.5:cloud"), the model state bleeds into the parent session's persistent state in sessions.json, causing the main session to unexpectedly switch models.

Steps to Reproduce

1. Configure a cron job with sessionTarget: "isolated" and a model override:

{
  "payload": {
    "kind": "agentTurn",
    "model": "ollama/kimi-k2.5:cloud",
    ...
  },
  "sessionTarget": "isolated"
}

1. Wait for the cron to run
2. Check the main session (agent:main:main) in sessions.json
3. Observe that model field is now set to the cron job's model

Expected Behavior

• Cron sessions with sessionTarget: "isolated" should have completely isolated state
• Model overrides in cron jobs should NOT affect the parent session's persistent model state
• Main session should retain its configured default model

Actual Behavior

• After cron runs, sessions.json contains:

{
  "agent:main:main": {
    "model": "kimi-k2.5:cloud",  // Wrong! Should be the default model
    ...
  },
  "agent:main:cron:<job-id>": {
    "model": "kimi-k2.5:cloud",  // Correct
    ...
  }
}

• The session JSONL shows a model_change event being written:

{"type":"model_change","id":"...","timestamp":"2026-04-07T06:47:33.548Z","provider":"ollama","modelId":"kimi-k2.5:cloud"}
{"type":"custom","customType":"model-snapshot","data":{"modelId":"kimi-k2.5:cloud",...}}

Evidence

From debugging session:

1. sessions.json shows corrupted state:

"agent:main:main": {"model": "kimi-k2.5:cloud"}

1. All cron sessions correctly have their own model:

"agent:main:cron:105b2013-...": {"model": "kimi-k2.5:cloud"}

1. Session key hierarchy appears to cause the bleed:

• Main session: agent:main:main
• Cron session: agent:main:cron:<job-id>
• The nested key structure under agent:main may be causing state inheritance issues

1. JSONL shows model_change events being written to main session file

Workaround

• Disable cron jobs that use model overrides, OR
• Use the default model for all cron jobs (no model override)

Root Cause Hypothesis

The session state management appears to share state between sessions with nested keys (agent:main:cron:... inherits from agent:main:...). When a model_change event is written, it's persisting to the parent session's state in sessions.json despite sessionTarget: "isolated".

The isolation should prevent:

1. model_change events from being written to parent session JSONL
2. Model state from persisting in parent session's sessions.json entry

Environment

• OpenClaw version: 2026.4.5 (3e72c03)
• Node: v22.22.2
• OS: Linux 6.17.0-20-generic (x64)

Impact

This breaks user experience when:

• Running multiple cron jobs with different model requirements
• Using specialized models for specific background tasks (e.g., dreaming, analysis)
• Expecting the main session to maintain its configured default model

Users may not notice until their main session unexpectedly starts using a different model, potentially affecting response quality, cost, or functionality.