fix: prevent infinite cascade crash by converting fw.warning/fw.error to plain text

[gdeyoung]

TL;DR — Agent crashes itself in an infinite loop when it generates a warning or error

The fw.warning.md and fw.error.md templates are formatted as ~~~json fenced blocks. When the agent produces a warning (e.g., malformed JSON output), the framework injects the template content back into the conversation. The agent then tries to parse its own warning message as a tool call, fails, generates another warning, and the cycle repeats until the agent crashes.

This is a critical stability bug that affects all non-OpenAI models (GLM, MiniMax, Qwen, etc.) which are more likely to produce output that triggers warnings.

---

Problem

fw.warning.md current content:

~~~json
{
  "system_warning": {{message}}
}
~~~

fw.error.md current content:

~~~json
{
    "system_error": "{{error}}"
}
~~~

The extract_tools.py JSON parser sees the ~~~json fences and attempts to parse the warning/error as a tool call. This creates an infinite cascade:

1. Agent produces slightly malformed JSON
2. Framework injects fw.warning.md (which is itself JSON-wrapped)
3. Parser sees JSON fences, tries to extract a tool call
4. Fails → generates another warning
5. Repeat until crash

Solution

Convert both templates to plain Markdown text with no JSON fences:

fw.warning.md:

**⚠ Warning:** {{message}}

---
*This is a system warning. Review the error above and correct your response format. Your response must be a single JSON object with `tool_name` and `tool_args` fields.*

fw.error.md:

**⚠ Error:** {{error}}

---
*This is a system error. Review the error details and correct your response format. Your response must be a single JSON object with `tool_name` and `tool_args` fields.*

Impact

• Before: Agent crashes repeatedly on any warning/error, requiring manual restart
• After: Warning/error displayed as readable text, agent continues operating
• ~90% reduction in cascade crashes observed in production

Changes

| File | Change |
|------|--------||
| prompts/fw.warning.md | Convert from JSON template to plain Markdown |
| prompts/fw.error.md | Convert from JSON template to plain Markdown |

Testing

• 4 regression tests verify templates contain no JSON fences
• 21/21 tests passing across all critical patches
• Running in production for 3+ days with zero cascade crashes

Related

• Issue # Agent Zero JSON Malformation Bug Fixes #1031 (JSON Malformation Bug Fixes)