Languages that are easy for AI models to write also make it easy for them to introduce bugs that are difficult to detect.
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Rust uses compiler-enforced type, memory, null, and concurrency safety to reject many errors before code runs.
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A Rust agent can compile its code, read detailed compiler errors, and fix problems in a loop, so first-pass difficulty becomes useful feedback.
Summary
Daniel Szoke argues that AI-assisted development should optimize for correctness feedback rather than code that an LLM can produce on its first attempt. Python, JavaScript, and TypeScript are familiar, well supported, and quick to run, but their flexibility lets agents write code with subtle bugs. Tests and review agents help, although they cannot check every possible input and can reproduce mistakes made in the implementation. Rust adds strict compiler checks for types, memory, null handling, and concurrency. Its compiler explains why code is rejected and often points to the type that caused the problem. Szoke demonstrates a shared counter that could compile in TypeScript and fail intermittently because of a data race. Rust rejects the same pattern and tells the agent that the captured value is not safe to send between threads. Rust can be harder to write correctly at first, but autonomous agents are well suited to compile, inspect errors, and revise code repeatedly.
Easy-to-write languages optimize for the wrong part of agentic coding
Python, JavaScript, and TypeScript are common, familiar, and supported by many libraries, frameworks, and examples. They are also quick to scaffold and run, and models often produce runnable code in the first try because the languages impose few constraints. Szoke questions whether first-pass fluency should be the goal. The same flexibility that helps an LLM write code also lets it make obvious or subtle mistakes. TypeScript's typing helps, but its any type weakens that protection, while typed Python has similar limits. Szoke's point is that a language can be harder for a model to write and still be better for an agent that can check and repair its work.
LLM errors need deterministic protection beyond tests and review
Szoke treats LLM mistakes as permanent risks because these systems are nondeterministic. Tests are useful, but an agent may write them after the implementation and test implementation details instead of behavior. Even test-driven development usually cannot check every possible input combination, so passing tests cannot prove that all outputs are correct. Test-generating agents and review agents can also make mistakes. Szoke connects this to Yuval Noah Harari's discussion in Nexus of 'alien intelligence': LLMs produce human language through a process unlike human thinking, so their failure modes can look unexpected. Code may have sensible names and comments while relying on a subtle heuristic or containing a hidden bug.
Rust makes the compiler enforce several classes of safety
Rust is a compiled language designed to combine the performance of C and C++ with memory safety and type safety. Szoke says that if Rust code compiles, developers can be reasonably confident that many types of bugs are absent because the compiler enforces invariants. The guarantees he names include strict type safety, null safety, and concurrency safety. Rust has no universal null value. An optional value must be represented explicitly, and the compiler requires a check before the inner value is accessed. Rust also does not provide an any type or an unchecked cast as an easy escape from its type system. Its compiler errors give people and agents context about what went wrong and how to fix it.
Rust rejects a shared mutable counter before a data race can run
Szoke shows code that starts a counter at zero, creates 100 threads, and increments the counter from each thread. The expected result is 100, but the types used for the counter allow shared mutable data only within one thread and are not synchronized for multithreaded access. In TypeScript, comparable code might compile and run, then occasionally return a value other than 100. That intermittent failure could be hard to trace in a larger application. Rust rejects the code at compile time. Its error explains that the async block cannot be sent safely between threads, then identifies the captured counter as having type RC RefCell i32, which is not Send. An agent can use that detail to replace it with a thread-safe type.
Compiler failures give autonomous agents a useful repair loop
Rust's constraints make first-pass code harder for an LLM to get right, but Szoke says this is useful when the LLM operates inside an agent loop. The agent can compile its code, inspect failures, and change the implementation. Each compile error can expose a bug before it reaches production. Szoke also compares compiler feedback with review agents. He says Rust's compile time is still faster than asking an AI agent to review the code, and a review agent might miss errors that the Rust compiler is guaranteed to find. He does not reject tests or review agents. He presents the compiler as an additional safety layer that gives the agent a deterministic check.
