Lens: /api/layout intermittently returns HTTP 500 {"error":"JSON parse failed"} (Linux/WSL2) #2907

Version

codebase-memory-mcp 0.12.1

Platform

Linux (x64)

Install channel

GitHub release archive / install.sh / install.ps1

Binary variant

standard

What happened, and what did you expect?

Galaxy/Architecture show "layout unavailable: /api/layout answered with HTTP 500: {"error":"JSON parse failed"}".
Expected: the graph is drawn.
The failure is intermittent: cbm-daemon.log has 102 lines of GET /api/layout status=500 response_bytes=29, interleaved with 200 responses (~266 KB). In the log, the oldest 500s appear before the first start of 0.12.1, so they seem to also happen with 0.11.0 (the log has no timestamps, so I can't confirm it).
Two older indexes of other projects open fine in the same browser. The UI log also repeats "THREE.WebGLRenderer: Context Lost".

Reproduction

I could NOT reproduce it on public code yet. It happens on a private Python project (cannot be shared): mode full, 1644 nodes, 4497 edges, 658 Section nodes from 71 .md files, MENTIONS and REFERENCES_FILE edges.

1. codebase-memory-mcp daemon start --port=9749
2. Open http://127.0.0.1:9749 in Chrome (Windows host, daemon in WSL2) and open the project in Galaxy or Architecture.
3. Actual: "layout unavailable" (HTTP 500 JSON parse failed). Expected: the graph is drawn.
   I can try to reproduce with a public repository with many .md files if that helps.

Logs

Diagnostics trajectory (memory / performance / leak issues)

Project scale (if relevant)

No response

Confirmations

• I searched existing issues and this is not a duplicate.
• My reproduction uses shareable code (a dummy snippet or a public OSS repository), not proprietary code.