fix(agent): add backwards compat for agent messages array

[waleedlatif1]

Summary

• add backwards compat for agent messages array

Type of Change

• Bug fix

Testing

Tested manually

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Preview	Comments	Updated (UTC)
docs	Skipped			Nov 20, 2025 7:15pm

[greptile-apps]

Greptile Overview

Greptile Summary

Added backwards compatibility for agent blocks to preserve legacy fields (systemPrompt, userPrompt, memories) during serialization. This ensures old workflows exported before the messages array migration (introduced in #2023) can still be imported and executed correctly.

Changes:

• Added isAgentBlock flag to identify agent blocks in extractParams method
• Introduced isLegacyAgentField check that includes legacy fields even if they're not in the current block config
• Modified the field inclusion logic to handle both current config-based fields and legacy fields

How it works:
The serializer now checks if a field is a legacy agent field (systemPrompt, userPrompt, or memories) and includes it in the params even if it's not present in the current block configuration. The existing migrateAgentParamsToMessages function (line 46-96) then converts these legacy fields into the new messages array format during deserialization.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The change is a focused, well-implemented backwards compatibility fix that only affects agent blocks during serialization. The logic is clear, correctly scoped to the specific use case, and aligns with the existing migration pattern already present in the codebase (migrateAgentParamsToMessages function). The implementation is non-breaking and defensive.
• No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
apps/sim/serializer/index.ts	5/5	Added backwards compatibility logic to preserve legacy agent block fields (systemPrompt, userPrompt, memories) during serialization, ensuring old workflows exported before the messages array migration can still function correctly

Sequence Diagram

sequenceDiagram
    participant WF as Workflow (Old Format)
    participant S as Serializer.extractParams
    participant BC as Backwards Compat Logic
    participant E as Executor

    Note over WF: Legacy agent block with<br/>systemPrompt, userPrompt, memories

    WF->>S: Serialize agent block
    S->>S: Identify isAgentBlock = true
    S->>S: Loop through subBlocks
    
    alt Legacy field (systemPrompt/userPrompt/memories)
        S->>BC: Check isLegacyAgentField
        BC-->>S: True (even if not in config)
        S->>S: Include field in params
    else Current field
        S->>BC: Check subBlockConfig exists
        BC-->>S: True
        S->>S: Include field in params
    end
    
    S-->>E: Serialized params with legacy fields
    
    Note over E: migrateAgentParamsToMessages<br/>converts old format to messages array

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[greptile-apps]

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