Significant increase in cpu startup time

[dnyg]

After adding the Cloudflare Agent AIChatAgent class and exporting it in my main file, running wrangler deploy often results in:

[ERROR] Your Worker failed validation because it exceeded startup limits

I have used the Cloudflare tool npx wrangler check startup to generate a worker-startup.cpuprofile and I use this bash script to output the duration

jq -r '(.endTime - .startTime) / 1000' worker-startup.cpuprofile

My current worker has a startup time of 31ms without the agent, and over 200ms with the agent. I tried to use dynamic imports to defer the imports to runtime, and it improved the situration a bit, but it was still very high. Unfortunately, I can't defer the AIChatAgent class that my class extends.

I then created this very very minimal test repo: https://github.com/dnyg/cf-agent-test

Here I have an example of a worker with only "agents" as a dependency and a hardcoded fetch response along with an implementation of AIChatAgent where everything is default.

Without the agent this worker has a startup time of 13-14ms. With the worker it is 34ms (a big increase - 250% - but not as breaking as what I'm experiencing on my actual worker).

As I understand, it is not possible to point to the location of your Durable Object within your wrangler.jsonc file - it has to be exported in the main file.

I am not sure what exactly is causing my cpu startup time to skyrocket, but I assume it might be differences in versions of the ai and zod packages within my project, and agents.

Any ideas to what I can do to again be able to deploy? For now I will probably just move it to a seperate worker, and suffer the cpu startup time there.

[threepointone]

Can you try setting build.minify as true in your vite config?

[dnyg]

The build.minify is currently set to esbuild. Changing it to true didn't help a lot in my project. The minimal test repo I made doesn't use vite at all

[threepointone]

Thanks for the repro, I'll have a look

[threepointone]

investigating this here cloudflare/workers-sdk#10723

[dnyg]

I saw this PR that attempts to fix the issue, and actually does quite a lot of good things. But I have a comment on what is causing the remaining problems #544 (comment)

The problem is definitely the ajv package, and it is used by @modelcontextprotocol/sdk

[whoiskatrin]

@dnyg the changes should be in the latest version, let me know if there are any issues