Mastra•3w ago

`mastra dev` generating malformed provider-registry.json on every execution

Hi! I’ve got an error that has started happening consistently on my machine but not on any of my coworkers, and I’m looking for some guidance from someone who works with the Mastra source - I think it’s likely an easy fix for someone familiar with the codebase. I'm not sure if I can provide any reproduction given how my coworkers don't have this issue with the same codebase. - Mastra's auto-generated provider-registry.json becomes malformed on my machine every time for unknown reasons - This could be bypassed if I could turn off dynamic loading but there does not appear to be a way to do that without me editing the code directly. - Relevant code: packages/core/src/llm/model/provider-registry.ts - This means mastra dev doesn't work on my machine at all without some very awkward workarounds. I'm still investigating why the JSON file is malformed on my machine, but I could do with some advice on this. When I run mastra dev but not with build + start:

Error: Failed to load provider registry with dynamic loading. Make sure provider-registry.json is generated by running: npm run generate:providers

Tried paths:
[...]/packages/mastra/node_modules/@mastra/core/dist/provider-registry.json: Unexpected non-whitespace character after JSON at position 77837 (line 2483 column 2)
[...]
    at loadRegistry (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2234:9)
    at _GatewayRegistry.getProviders (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2459:18)
    at Object.ownKeys (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2249:32)
    at Function.entries (<anonymous>)
    at getStaticProvidersByGateway (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2497:36)
[...]]

Error: Failed to load provider registry with dynamic loading. Make sure provider-registry.json is generated by running: npm run generate:providers

Tried paths:
[...]/packages/mastra/node_modules/@mastra/core/dist/provider-registry.json: Unexpected non-whitespace character after JSON at position 77837 (line 2483 column 2)
[...]
    at loadRegistry (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2234:9)
    at _GatewayRegistry.getProviders (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2459:18)
    at Object.ownKeys (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2249:32)
    at Function.entries (<anonymous>)
    at getStaticProvidersByGateway (file://[...]/packages/mastra/node_modules/@mastra/core/dist/chunk-II37LKES.js:2497:36)
[...]]

GitHub

mastra/packages/core/src/llm/model/provider-registry.ts at c00f6140...

The TypeScript AI agent framework. ⚡ Assistants, RAG, observability. Supports any LLM: GPT-4, Claude, Gemini, Llama. - mastra-ai/mastra

44 Replies

aprilOP•2w ago

My own investigation - It's in Mastra's new model provider registry feature. - (I think?) This feature auto-loads models in dev mode but not in production mode, which explains this behaviour somewhat. - We don't actually use this feature at this time. - The file [...]/packages/mastra/node_modules/@mastra/core/dist/provider-registry.json: - This file exists - This file is malformed JSON. My guess - two different sources write to this file, one overwriting the other, leaving a malformed part at the very end that looks like this:

       // ... rest of JSON ...
             "openai/o4-mini"
           ]
         },
         "version": "1.0.0"
       }mini" // malformed from this line
           ]
         },
         "version": "1.0.0"
       }

       // ... rest of JSON ...
             "openai/o4-mini"
           ]
         },
         "version": "1.0.0"
       }mini" // malformed from this line
           ]
         },
         "version": "1.0.0"
       }

- I don't know why this is happening on my machine so far. - This file regenerates itself every time mastra dev is executed, so I can't even bypass this by fixing the JSON. And some more (discord message limits make this a bit hard so this might be harder to read than I'd like) - The error occurs in function loadRegistry (originally in src/llm/model/provider-registry.ts it seems) - loadRegistry will fall back on a default if it's argument useDynamicLoading is false, so if I could ensure that was the case it would likely be a good workaround - loadRegistry is called by _GatewayRegistry.getProviders - The _GatewayRegistry singleton has the following logic: this.useDynamicLoading = options.useDynamicLoading ?? isDev2 - Commenting out this line fixes the issue(since useDynamicLoading will be false) - When I run this, options.useDynamicLoading is undefined, isDev2 is true - const isDev2 = process.env.MASTRA_DEV === "true" || process.env.MASTRA_DEV === "1"; - in my case MASTRA_DEV=true, even though I've attempted to set it to false in my environment to no effect. I should also add that mastra has worked without issue on my machine for months, and no change preceded this issue, it just started happening while I was running some tests.

Mastra Triager•2w ago

📝 Created GitHub issue: https://github.com/mastra-ai/mastra/issues/10434 🔍 If you're experiencing an error, please provide a minimal reproducible example whenever possible to help us resolve it quickly. 🙏 Thank you for helping us improve Mastra!

Abhi Aiyer•2w ago

Hi @april such a strange issue. We'll look into why this is happening and see if we can resolve it! Can you provide me all your package versions?

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`mastra dev` generating malformed provider-registry.json on every execution

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