Proposal: Versioned Debug Info Metadata for Daml

Walnut proposes a debug metadata format for Daml, compiler support to emit it, a runtime trace, a verifier and reader library, source-level debugging in dpm trace and dpm debug, an adoption milestone, and a 12-month maintenance window.

The draft format specification and its JSON Schema live alongside the prototype compiler.

Development Fund Proposal Submission

Proposal file:
/proposals/2026-08-Walnut-daml-debug-info-metadata.md

Applicant

Organization:
Walnut

Author / Primary Contact:
Djordje Todorovic (djordje@walnut.dev) Roman Mazur (roman@walnut.dev)

Champion:
Needs Champion for now.

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Proposal Classification

Proposal Type:

• RFP-aligned proposal
• Individual initiative

RFP / Roadmap Area:
The RFP is #19.

Label: daml-tooling

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Funding & Timeline

Total Funding Request:
3,360,000 CC

Project Duration:
18 months (6 months delivery and adoption, followed by a 12-month maintenance window)

Maximum Amount:
N/A

Maximum Duration:
N/A

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Summary

When a Daml workflow fails on Canton, the developer sees an error message and a package id, not the line of Daml that failed. We will define a debug metadata format for Daml, make the compiler emit it, and build the tooling that reads it, including dpm debug, a source-level debugger. Putting that mapping in the compiler once means every Canton tool gets the same answer instead of each one guessing at it separately.

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Submission Checklist

• Full proposal file is included in this PR
• Organization and primary contact identified
• Champion identified or Needs Champion selected
• RFP / roadmap alignment identified, if applicable
• Total funding request provided
• Project duration provided
• Proposal is within any RFP maximum amount
• Proposal is within any RFP maximum duration
• Milestones and milestone funding are defined in the proposal
• Acceptance criteria are based on ecosystem value
• Architectural alignment is addressed