feat: Implement MCP server instruction fetching and integration

[seuros]

Now the LLM can see the instructions that that the server emit at initialisation.

The data was where, just not used.

Fixes #7373

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[jcdickinson]

Confirmed working on my side. Before, After.

[altendky]

Thanks for this! I just discovered myself that the instructions are not presented to the model. No wonder it was doing silly things. :] Maybe a little activity here will help get some attention and move this along. I had a couple questions as I read through the changes.

I noticed getInstructions() on the SDK client is a synchronous getter (it just reads a field set during initialize). Was there a reason you wrapped it in an async helper with try/catch? Relatedly, create() already runs for all three paths (init, connect(), add()), so I was wondering if reading it there would avoid needing the separate function — and would also pick up instructions on reconnect/add, which I think the current version misses?

On the refresh functions and InstructionsChanged event — are those intended for a follow-up, or is there something I'm not seeing? I couldn't find an MCP protocol notification for instructions changing mid-session (unlike notifications/tools/list_changed for tools), so I wasn't sure what would trigger them.

Thanks for submitting the feature request and providing an implementation here. I'm hoping we get to start using this soon!

[altendky]

thanks! a few more detailed comments here. to be clear, i'm just another contributor looking to get this merged, but after we get done here i'll bring it up in discord. hopefully with two of us involved it can float above the masses. :]

[altendky]

looks good to me. thanks @seuros!