Agent-first coding: use the frontier tools and pay for them
Claude Code or OpenAI Codex, desktop app or command line. Generic and budget setups hide what the new tools can do.
What agent-first means
| Editor-first | Agent-first | |
|---|---|---|
| You | Type the code | Describe the outcome |
| The tool | Completes your line | Reads the repository, edits files, runs commands |
| You check | Each line as you write it | The diff and the output |
| Good for | Small edits | Pipelines whose result you can verify |
One session looks like this.
Research code suits this. It is scripts and pipelines run from a command line, and the questions have checkable answers: did the pull return the right rows, does the regression reproduce the table.
“Claude Code or VS Code” is the wrong comparison. VS Code’s own documentation now describes agents that “find relevant code, make changes, and run checks without you directing each search, edit, and test run.” The editor is one of several places an agent runs. The question is which agent.
Stick to the frontier
Today that means Claude Code or OpenAI Codex, as a desktop app or on the command line.
| Claude Code | OpenAI Codex | |
|---|---|---|
| Made by | Anthropic | OpenAI |
| Runs in | Terminal, IDE, desktop app, browser | ChatGPT desktop app, command line, IDE extension, cloud |
| Gets first | Anthropic’s finance agent templates, as plugins | OpenAI’s research tooling, bundled in its academic program |
The cost of economizing is invisible. You never see the analysis you did not attempt, so you conclude the technology is modest.
When you cannot use them
Some schools restrict which vendors may receive code or data, and some data cannot leave your machine at all. Then use OpenCode, an open source agent that lets you choose the model provider, or a local model. Our OpenRouter and Bedrock comparison covers where that access comes from.
Treat this as the exception. Expect less from it, and do not judge the technology by it.
The layers you can delete
Two years of tooling grew up around weaker models: orchestration frameworks, output parsers, retry wrappers, routers. Much of it is now optional.
Anthropic’s engineering team wrote in December 2024 that the most successful teams they worked with “weren’t using complex frameworks or specialized libraries.” Their advice: find “the simplest solution possible,” because frameworks “often create extra layers of abstraction that can obscure the underlying prompts and responses, making them harder to debug.” They suggest calling the model API directly.
The author of 12-Factor Agents, a guide from HumanLayer, reports the same thing from the field: “I don’t see a lot of frameworks in production customer-facing agents.” Most of what the author sees is “mostly deterministic code, with LLM steps sprinkled in at just the right points.”
For a research pipeline:
| Layer | Verdict | Why |
|---|---|---|
| Orchestration framework | Delete | A loop in a script is easier to read, debug and put in a replication package |
| Parse-and-retry wrapper around JSON | Delete | Model APIs now offer structured outputs that, in Anthropic’s words, “guarantee schema-compliant responses through constrained decoding” |
| The output schema | Keep | You still have to say which fields you want. Anthropic’s own Python example writes it with Pydantic |
| Checks where outside data enters | Keep | Row counts, key uniqueness, date bounds. An agent removing layers should never remove these |
So “you don’t need Pydantic” is half right. The retry machinery built around it can go. A typed schema is still the clearest way to state the output.
The test for any layer: if you cannot say what it does that twenty lines of your own code would not, delete it and see what breaks.
References
- Claude Code overview code.claude.com
- Codex documentation, OpenAI developers.openai.com
- Agents for financial services, Anthropic (2026) anthropic.com
- Accelerating scientific discovery with ChatGPT for Academic Researchers, OpenAI (2026) openai.com
- Sharing AI progress in mathematics, OpenAI (2026) openai.com
- OpenCode documentation opencode.ai
- Build with AI in VS Code code.visualstudio.com
- Building Effective AI Agents, Anthropic (2024) anthropic.com
- 12-Factor Agents, HumanLayer github.com
- Structured outputs, Claude Platform Docs platform.claude.com