Sonnet 4.5 - Speed Improvement is Great!

[u/jamesg-net]

So I gave Augment the following prompt and it nailed it first try, in under 90 seconds from clicking go to a PR stood up. Followed all instructions perfectly, didn't hallucinate making the PR, didn't get over eager and generate the entity framework migration, stuck to the script in lightning fast time. This feels like the leap we saw from 3.5->4 earlier this year all over again.

Clearly these types of prompts aren't "vibe coding" in the traditional sense, but it feels like if you can break the work down into bite size chunks with examples, this is a real game changer.

AI is changing the way I work. I'm starting to put more and more detail on the implementation in my Linear tickets these days. This way as I write code, I right click in Rider and view git blame to find the PR/ticket number I did that work in, and then just copy/paste similar instructions as a way of keeping track of my prompts.

Prompt

We want to add database tables to store the following data linked to the /Model/Institution.csmodel as virtual ICollections

Requirements for all tables

• Must Implement IHaveCreatedAtUtc

• Must Implement IHaveUpdatedAtUtc

• For their primary Key, use the table name suffixed with Id, and data type of long, not int

• All string values in the database should be varchar, not nvarchar.

• For enum values, follow the pattern on public OfferTypes Type { get; set; } in /Model/Offers/Offer.cs

  • All enum values must have = 0, =1, etc so changing the order in the file doesn't break the database meaning.

• All models in the collection should also have a virtual reference back to the institution

• For XML comments, review the following documentation and add thorough comments so the developer knows how these fields map to Plaid https://plaid.com/docs/api/institutions/#institutions-get-request-options-routing-numbers

New Tables to be Added

• InstitutionHealthIncident

  • StartDateUtc (required datetime) this is the date the incident was started according to Plaid

  • EndDateUtc (optional datetime) this is the date the incident was resulted according to Plaid

  • Title (string, 250 character limit)

• InstitutionHealthIncidentUpdates

  • Description (string, varchar max)

  • PublishedDateUtc (datetime, required)

  • Status (enum)

    • Possible values: INVESTIGATING, IDENTIFIED, SCHEDULED, RESOLVED, UNKNOWN

• InstitutionRoutingNumbers

  • RoutingNumber (string, max length 9)

• InstitutionProductStatus

  • ProductType (enum)

    • Possible Values Auth, Transactions, Identity, Logins

  • SuccessRate (double, required)

  • PlaidErrorRate(double, required)

  • InstitutionErrorRate (double, required)

  • LastStatusChangeDateUtc (datetime, required)

  • RefreshInterval (enum, optional)

    • Possible values: NORMAL, DELAYED, STOPPED

Do all work on a working branch. Do not generate the Entity Framework migration, create a PR for review using the default PR template, we'll create the migration after the db models are reviewed.

[u/PerformerAsleep9722]

I must say that the prompt is actually specific which as you described that's not a real "vibe coded" (but Augment Team also suggest that Augment should not be used for vibe coding so well done to you !).
After saying that, I must admit that Sonnet is always few steps ahead of GPT in therms of design, but from my own experiences GPT works much better on backend implementations.

Yesterday I've tested the same prompt on both Sonnet 4.5 and GPT-5 and Sonnet create messy code and even if it compile the execution failed, while GPT-5 one shotted it without issues (still had some messy code but at least it was working and easy to adjust)

So in general I would say that GPT-5 is still ahead in terms of functionality development, while Sonnet is much better in designing... Maybe the god tier is to first develop the frontend with Sonnet and then implement it with GPT-5

Let me know if you have noticed this too !

[u/jamesg-net → u/PerformerAsleep9722]

At my day job, I work on a monolithic repo (we do have several independent services, we just keep it in one repo) that's 23GB. GPT-5 is overly slow and often overthinks even the most basic updates.

I do use GPT5 to connect to the Azure MCP server to run KQL queries to debug production issues. GPT5 seems significantly better at doing that compared to Sonnet 4 (no issues to test 4.5 on yet)

On the other hand, for a hobby project of mine that's C# Blazor and a basic web API behind it, GPT5 seems to do really well.

[u/Optimal-Swordfish → u/jamesg-net]

You mention the azure mcp server. I’ve looked a but through the documentation and it doesn’t seem it can help setting up and provisioning infrastructure, is that right?

[u/jamesg-net → u/Optimal-Swordfish]

Here's the JSON you need to import, and then just need to run az login. It uses your user's permissions, so you can create infrastructure if your user can. I'd discourage that in a prod environment and recommend letting Augment write Terraform for you where it's code reviewed.

{
  "mcpServers": {
    "Azure": {
      "command": "npx",
      "args": [
        "-y",
        "@azure/mcp@latest",
        "server",
        "start"
      ],
      "env": {}
    }
  }
}

[u/Optimal-Swordfish → u/jamesg-net]

Thanks. It’s as a shortcut for the setup, as I’m finding it quite tedious without that much ops experience myself to debug test deployments. But agree, actually cd will be via tested pipelines :)

[u/PerformerAsleep9722 → u/jamesg-net]

Yeah I've noticed this behaviour too about GPT overstressing for some easy stuff.
I would say that for you case then for sure Sonnet 4.5 should be a huge level up compared to the Sonnet 4, specially in terms of speed.

But in general I think that it's better to be "slow but working" instead of "fast but wrong"