MCP Configuration
Malformed .mcp.json breaks all servers
A JSON syntax error anywhere in .mcp.json can prevent the whole file from parsing, taking every server in it down at once, not just a specific entry.
Because .mcp.json is a single JSON document, an invalid file doesn't fail gracefully per-server — it fails to parse at all, and every server that would have been defined in it simply isn't loaded.
This is worth ruling out first whenever multiple, previously-working servers all go missing at once, especially right after a manual edit to the file — a missing comma or an extra trailing one is enough.
Running the file through any JSON validator is a faster first check than reasoning about it by eye, particularly in a large config with several servers defined.
Validate .mcp.json with any JSON linter before assuming a specific server is the problemFrequently asked questions
What does Malformed .mcp.json breaks all servers do in Claude Code?
A JSON syntax error anywhere in .mcp.json can prevent the whole file from parsing, taking every server in it down at once, not just a specific entry.
How do I use it?
Try: Validate .mcp.json with any JSON linter before assuming a specific server is the problem
Any caveats to know about?
Running the file through any JSON validator is a faster first check than reasoning about it by eye, particularly in a large config with several servers defined.
Is this covered in the Claude Code Toolkit?
Yes — Malformed .mcp.json breaks all servers and patterns like it are part of the full command, hook, and template pack included with a Claude Code Toolkit subscription.
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