Code & Integration Agent
API plumbing, schema mapping, OpenAPI client generation, internal tooling
What a code agent actually is
A code and integration agent is a system that takes a structured engineering task — "generate a typed TypeScript client for this OpenAPI spec," "map fields from system A to system B with these transformations," "build a small internal tool to view this Firestore collection with filters and sort" — and produces working, tested, reviewable code.
It is not:
- Autocomplete in your editor (that's Copilot / Cursor / Claude Code; we use those, but they're the substrate).
- An AI that "writes your whole app." That's a marketing fiction.
- A senior engineer replacement. It is a force multiplier for senior engineers, not a substitute.
It is a defined workflow with: scoped task definition, eval/test suite, structured diff, CI pipeline, human approval for risky changes, and observability.
Where it earns its keep
The work software teams routinely lose weeks on:
- API client generation. OpenAPI exists, but the typed client doesn't, or it's out of date, or the codegen tool you used got abandoned three years ago.
- Schema mapping. System A has fields
customer_id, total_eur. System B wantscustomerRef, amount.value, amount.currency. Six pages of mappings, all boring, all important to get exactly right. - Internal tools. "I just need a page that lists pending approvals with sorting and filters and a one-click action." A senior engineer can build that in a day; the senior engineer is busy. The agent ships it in 90 minutes.
- Migration scripts. Old schema → new schema with data transforms. Manual is risky; the agent generates with tests against fixture data.
- Documentation. OpenAPI spec from real traffic. README from code. Architecture diagrams from imports. Boring, valuable, never done.
Anatomy of a working code agent workflow
[Task definition (structured)]
↓
[Context gathering: read relevant code + docs + schemas]
↓
[Plan: list of files to change with rationale]
↓
[Implementation: generate diffs file-by-file]
↓
[Tests: generate + run; iterate on failures]
↓
[Self-review: agent re-reads its own diff against the task]
↓
[Open PR with summary, plan, tests run, manual checklist]
↓
[CI: lints, types, tests, security scan]
↓
[Human review (mandatory for risky classes)]
↓
[Merge + deploy]
The shape is similar to how a careful junior engineer would work — small diffs, mandatory tests, approval gates. The difference is throughput.
Risk classes and autonomy
| Task class | Example | Autonomy |
|---|---|---|
| Low risk, well-tested | Generated API client, type definitions, fixture updates | Auto-PR, auto-merge if CI green |
| Medium risk | Refactor, internal tool, glue logic | Auto-PR, human review |
| Higher risk | Schema mapping, integration boundary, business logic | Human design review, then PR |
| High risk | Database schema change, payment flow, auth | Always human-driven, agent assists |
We tune the autonomy dial per organisation based on test coverage, change tolerance, and how much trust you've built with the agent.
Stack we tend to reach for
| Layer | Default |
|---|---|
| Coding LLM | Claude Sonnet 4.6 / Claude Code |
| Task orchestration | Custom workflow (or LangGraph for multi-step planning) |
| Code analysis | TypeScript AST + ts-morph for surgical edits |
| Testing | Vitest / Jest depending on stack |
| OpenAPI | openapi-typescript + custom validators |
| Schema validation | Zod end-to-end |
| Diff review | GitHub PRs with bot-generated summaries |
| Eval | Snapshot tests + behaviour assertions |
How we use code agents inside our own builds
Honest answer: every engagement we ship now uses code agents internally. They write the API clients, the schema validators, the test fixtures, the migration scripts, the internal admin tools, the OG image variants, the boilerplate around the actual interesting work. A 12-week production build today ships closer to what would have been 20 weeks two years ago, at the same headcount.
We do not use code agents to write the interesting parts — product UX, novel architecture, performance-sensitive systems. Those are human-driven with the agent as an accelerator for the boring bits.
Our The AI Development playbook post walks through how this changes our internal process.
Cost and timeline
| Scope | Investment |
|---|---|
| Single code-agent workflow deployed into your stack | €8,000–20,000 |
| Multi-workflow code-agent platform (3–5 workflows) | €25,000–60,000 |
| Code-agent capability inside your engineering team (training + custom workflow + retainer) | €40,000–100,000 + ongoing |
Most of our clients access this capability as a force multiplier on their existing engagements with us, not as a standalone product.
Where it pairs
Code agents commonly chain with:
- Document processing agents when documents drive code (e.g. generate client SDKs from a vendor's API documentation PDF).
- Workflow orchestrators when generated code is part of an automation pipeline.
- Research agents when the code task starts with "figure out how this third-party system works."
If you have an engineering bottleneck on the kind of boring-but-important code we described, drop us a note. One paragraph is enough.
Frequently asked questions
Related
Custom Development
Web apps, mobile apps, dashboards, internal tools. React, Next.js, React Native, Power Apps — picked for the job, not the hype.
The AI Development playbook: how we ship agents in 6 weeks
We ship production AI agents in 6 weeks by being opinionated about tools, refusing to skip discovery, building evals from day one, and treating code agents as a force multiplier. This is the playbook — what we use, what we refuse, and why it lands consistently.
From PowerApps to production: when low-code stops scaling
PowerApps is excellent for many Microsoft 365 organisations until it isn't. It hits ceilings around concurrent users, complex business logic, performance, and developer ergonomics. The migration path is rarely 'rewrite everything in Next.js' — it's hybrid: keep PowerApps for what it's good at, move the parts where it's failing to TypeScript on Cloud Run.
Hiring an AI development agency: 12 questions to ask
Twelve questions that separate serious AI dev shops from demoware vendors. Asks about evals, observability, code ownership, provider lock-in, references, and what they'll refuse to do. If a vendor can't answer cleanly, walk.
Want to scope a code & integration agent project?
Tell us the workflow. We'll come back within one business day with a clear next step.