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What Coding Agents Can Actually Do Today — and What They Can't

January 28, 20268 Min.
Philip Blatter
Philip Blatter
Founder & CEO

An honest look at the state of the art. Where AI agents excel, where they fail, and how to set realistic expectations.

The Honest Assessment

Between "AI will replace all developers" and "AI can only produce toy code" lies reality. And it's more nuanced than either side admits.

Here's an honest overview of where things stand in early 2026.

Where Coding Agents Excel

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CRUD Operations and REST APIs

The bread and butter of every AI. Defining endpoints, writing database queries, implementing validation — this works reliably and quickly. Why? Because there are millions of examples and the patterns are clearly defined.

Expected quality: 85–95% production-ready on the first pass.

Automated Tests

Surprisingly good. Agents write unit tests, integration tests, and even E2E tests that cover meaningful edge cases. Often better than what many developers produce under time pressure.

Expected quality: 80–90% usable, the rest needs human adjustment.

Refactoring and Code Migration

Codebase-wide restructuring — such as a framework update or an API migration — is handled by agents faster and more consistently than human teams. They don't forget a file and don't make careless errors.

Expected quality: 90%+ with clear transformation rules.

Boilerplate and Scaffolding

Setting up project structures, creating standard configurations, implementing repetitive patterns. Agents are unmatched in efficiency here.

Expected quality: 95%+. This is solved.

Documentation

Auto-generated code documentation, README files, API docs. The AI understands the code and often describes it more clearly than the author.

Expected quality: 85–90%, rarely worse than human-written docs.

Where Coding Agents Fail

Complex Architecture Decisions

"Should we use event sourcing or CRUD for this service?" — This question requires understanding of business requirements, team size, future scaling, and organizational constraints. No agent can do this.

Unclear Requirements

"Make it somehow better" is not a good prompt — for any agent. AI needs clarity. If you don't know what you want, the AI won't know either.

Performance Optimization in Edge Cases

Standard optimizations (caching, indexing, query optimization) are within agents' capabilities. But highly specialized performance work — memory layout optimization, lock-free concurrent data structures — remains human work.

Security-Critical Cryptography

Custom crypto implementations, zero-knowledge proofs, timing attack prevention — human security experts are irreplaceable here. AI reproduces known patterns, but security often requires the opposite: thinking against the grain.

Domain-Specific Business Logic

When the logic only exists in the heads of the business department and isn't documented anywhere, AI can't implement it. Garbage in, garbage out.

The Useless Metrics

A common mistake: measuring the value of AI development by individual lines of code.

Meaningless:

  • "AI wrote 80% of the code"
  • "We generated 500 lines per day"

Meaningful:

  • "Time-to-feature dropped from 3 weeks to 4 days"
  • "The change failure rate has been cut in half"
  • "We deploy 4x more often than 6 months ago"

The Pragmatic Approach

Instead of treating AI as a silver bullet or a toy:

  1. 1.Identify the 80% — Which tasks in your sprint are standardized enough for AI?
  2. 2.Keep the 20% — Architecture, strategy, complex domain logic stays with humans
  3. 3.Measure outcomes, not output — Velocity, quality, satisfaction instead of lines of code
  4. 4.Iterate — Start small, learn, expand

Honesty about AI's limitations isn't an admission of weakness. It's the foundation for a strategy that actually works.

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