youichi-uda/godot-mcp-pro

v1.13.2 Breaking

This release includes breaking changes for platform teams planning a safe upgrade.

Published 21d MCP Developer Tools

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✓ No known CVEs patched

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✓ No known CVEs patched in this version

Topics

ai ai-tools claude cursor game-development gamedev

+7 more

gdscript godot godot-engine godot-plugin godot4 mcp model-context-protocol

ReleasePort's take

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editorial:auto 13d

v1.13.2 fixes a race condition in WebSocket port allocation that caused simultaneous Claude Code sessions to silently fail to bind. Sessions now fall back through ports 6505-6509 on collision.

Why it matters: Developers running multiple Claude Code instances with godot-mcp-pro previously encountered unexplained WebSocket failures. Port allocation now gracefully handles collisions, eliminating silent failures when parallel sessions compete for the same port.

Summary

AI summary

Fixed port allocation race where simultaneous Claude Code sessions would silently fail to bind a WebSocket server.

Changes in this release

Type	Severity	Summary	CVE
Bugfix	Medium	Port allocation falls back through 6505-6509 on bind collision Port allocation falls back through 6505-6509 on bind collision Source: llm_adapter@2026-05-21 Confidence: high	—
Bugfix	Medium	Removes misleading 'will retry on first command' log message Removes misleading 'will retry on first command' log message Source: llm_adapter@2026-05-21 Confidence: low	—

Full changelog

Bug Fix — Port allocation race between parallel Claude Code sessions

Two Claude Code sessions starting nearly simultaneously could both pre-check port 6505 as free, both attempt to bind, and the loser receive EADDRINUSE and silently give up. The losing session had no WebSocket server at all — every tool call failed for the remainder of its lifetime, with no recovery short of restarting.

The fallback log line claimed it would "retry on first command," but no such retry existed.

What's fixed

connect() now walks ports 6505–6509 in order and falls through to the next on EADDRINUSE. Only when the entire range is exhausted does it reject, with a clear error message
fixedPort=true (explicit GODOT_MCP_PORT) still fails fast on collision — useful for catching stale processes
Misleading "will retry on first command" log line removed

Verification

New tests/godot-connection.test.ts covers the race scenario directly: 5 simultaneous connect() calls all land on distinct ports. 5 new tests, 62 passing total.

Notes

This is a server-side fix. The addon (Asset Library) is unchanged from v1.13.1; the version bump there is just for label consistency
Affects everyone running multiple Claude Code sessions against Godot at once. If you only ever run one session, v1.13.1 behavior is unchanged

Credits

Reported by CrusherEAGLE on Discord 2026-05-13 — second clean repro report in two days, much appreciated.

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About youichi-uda/godot-mcp-pro

Premium MCP server for Godot game engine with 84 tools for scene editing, scripting, animation, tilemap, shader, input simulation, and runtime debugging.

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