26 Mistral Prompts for Coding (2026)

You are a senior [LANGUAGE] engineer. Write a function that [WHAT IT DOES]. Inputs: [INPUTS]. Output: [EXPECTED OUTPUT]. Constraints: [e.g. no external deps, must handle empty input, O(n) time]. Include inline comments only where the logic is non-obvious, and add 3 unit tests covering edge cases. Return one code block, then a two-line usage example.

Build a [React + TypeScript] [COMPONENT NAME] that [WHAT IT DOES]. Props: [LIST PROPS AND TYPES]. Requirements: accessible (keyboard + ARIA), handles loading and error states, and no styling library beyond [CSS / Tailwind]. Return the component in one file, then list any assumptions you made about props or behavior.

Write a [Python] command-line tool that [WHAT IT DOES]. It should accept these flags: [LIST FLAGS]. Validate inputs and print helpful errors, support --help, and exit with proper status codes. Keep it to the standard library if possible. Return the full script, then a few example invocations with expected output.

Design and implement a [POST] endpoint for [FRAMEWORK] that [WHAT IT DOES]. Define the request and response JSON schemas, validate input, handle the error cases [LIST], and return correct status codes. Include one example request and response. Note any auth or rate-limiting I should add but you are not implementing here.

Using the code interpreter, prototype [WHAT YOU WANT TO TEST, e.g. a parsing approach] in Python and actually run it on this sample input: [PASTE SAMPLE]. Show the output, then tell me whether the approach works, where it breaks, and what you would change before putting it in production. Keep the prototype small.

I am getting this error in [LANGUAGE / FRAMEWORK version]: [PASTE ERROR]. Here is the relevant code: [PASTE CODE]. Think step by step, find the root cause, and give me the corrected code. Explain what was wrong in two sentences. If more than one cause is possible, rank them by likelihood and tell me how to confirm each.

Explain this stack trace in plain terms and tell me where to look first: [PASTE STACK TRACE]. Point to the most likely line in my code, translate the error into what actually went wrong, and list the 3 most common causes of this error in [LANGUAGE / FRAMEWORK]. Do not rewrite my code yet — just diagnose.

This test passes sometimes and fails other times: [PASTE TEST + CODE UNDER TEST]. Diagnose the source of the flakiness — timing, shared state, ordering, randomness, or external calls — and give me a deterministic fix. Explain the root cause in two sentences and show the corrected test. Do not just add a retry.

This code is slow on [DESCRIBE INPUT SIZE]: [PASTE CODE]. Identify the bottleneck, explain the time and space complexity of the current approach, and propose a faster one with its complexity. Show the optimized code, and note any trade-off in readability or memory. Keep behavior identical.

Here is a bug report: [PASTE REPORT]. And here is the relevant code: [PASTE CODE]. Write the smallest failing test that reproduces the bug, explain what triggers it, then give the fix and confirm the test now passes. If you cannot reproduce it from what I gave you, tell me exactly what extra information you need.

Write thorough unit tests for this function using [TEST FRAMEWORK]: [PASTE FUNCTION]. Cover the happy path, edge cases, invalid inputs, and boundary conditions. Explain in one line what each test verifies, and flag any behavior in the function that looks like a bug or is ambiguous enough to need a spec decision.

Review this code as a senior engineer: [PASTE CODE]. Group your findings by severity — Blocker, Should-fix, Nit — and for each give the specific line, why it matters, and a concrete fix. Focus on correctness, edge cases, and readability over style preferences. End with the one change that would improve this the most.

Do a focused security review of this code: [PASTE CODE]. Check for injection, auth/authorization gaps, unsafe input handling, secrets in code, and unsafe dependencies. For each issue, give the risk, a realistic exploit scenario in one line, and the fix. Rank by severity. If something looks fine, do not invent a problem.

Add complete type hints and concise docstrings to this code without changing behavior: [PASTE CODE]. Use [PEP 484 / TypeScript] types, document parameters, return values, and raised errors, and keep docstrings to a few lines. Return the annotated code, then flag any place where the types revealed a possible bug or an unclear contract.

Explain what this code does to a developer new to [LANGUAGE / LIBRARY]: [PASTE CODE]. Give a one-paragraph overview, then a block-by-block walkthrough of the tricky parts, and call out any bugs, edge cases, or performance concerns you notice. Keep it concrete and skip the obvious lines.

Refactor this code for readability and maintainability without changing behavior: [PASTE CODE]. Improve naming, reduce nesting, and extract logic where it helps. Return the refactored version, then a short bullet list of what you changed and why. Keep it idiomatic for [LANGUAGE] and do not add dependencies or change the public interface.

This function runs on a hot path and needs to be faster: [PASTE CODE]. Keep the same output for all inputs. Propose the single highest-impact optimization first, show the code, and state the new complexity and the trade-off. Then list any lower-impact wins as a short bullet list I can decide on later.

These files have repeated logic: [PASTE CODE]. Extract the shared behavior into a well-named helper or module without changing behavior, and update the call sites. Do not over-abstract — only pull out what is genuinely the same. Return the new shared code plus the updated call sites, and explain the boundary you chose.

Migrate this code from [OLD LIBRARY/VERSION] to [NEW LIBRARY/VERSION]: [PASTE CODE]. List the breaking changes that affect me, update the code accordingly, and flag anything that has no direct equivalent and needs a decision. Keep behavior identical where possible and note any behavior that necessarily changes.

Convert this [SOURCE LANGUAGE] code to idiomatic [TARGET LANGUAGE]: [PASTE CODE]. Do not transliterate — use the target language's idioms, standard library, and error-handling conventions. Preserve behavior, note any place the languages differ in a way that matters (types, concurrency, null handling), and add a couple of tests to prove equivalence.

Write a [PostgreSQL] query for this request: [WHAT I WANT]. Here is the schema: [PASTE TABLES / COLUMNS]. Return the query, a one-line explanation of each join or filter, and a note on indexes that would keep it fast at scale. If my request is ambiguous, state the assumption you made and offer the alternative.

Build a regex for [LANGUAGE / FLAVOR] that matches [WHAT TO MATCH] but not [WHAT TO EXCLUDE]. Give me the pattern, a plain-English breakdown of each part, and 5 test strings (3 that should match, 2 that should not) with the expected result for each. Keep it as simple as the task allows.

Write a production-ready Dockerfile for a [STACK, e.g. Node 22 + pnpm] app. Use a multi-stage build, run as a non-root user, keep the image small, and cache dependencies well. Explain each stage in one line, and list two things I should add for a real deployment (health check, .dockerignore, etc.) that you did not include.

Write a [GitHub Actions] CI workflow for a [STACK] project that runs on pull requests: install, lint, type-check, test, and build. Cache dependencies, fail fast, and run the matrix over [VERSIONS]. Return the YAML with a one-line comment on each job, and note anything I should add for deploys but you are leaving out.

Write a precise task spec for a Vibe cloud agent to run end to end in an isolated sandbox: [DESCRIBE TASK, e.g. upgrade dependency X and fix resulting breakages]. Include exact acceptance criteria, the files or areas it may touch, what it must NOT change, the tests that must pass, and how it should report back. Keep it unambiguous so it needs no follow-up.

Here is my diff: [PASTE DIFF]. Write a conventional-commits message (type, scope, concise subject, body explaining the why) and a pull-request description with sections: What changed, Why, How to test, and Risks. Keep it factual and skip anything the diff does not support.