# How to Inspect an Autocomplete Completion

> Inspect an autocomplete completion by checking the surrounding contract, its hidden defaults, and the smallest test that shows whether the proposed lines belong there.

- Canonical HTML: [https://unrust.dev/use-cases/inspect-an-autocomplete-completion](https://unrust.dev/use-cases/inspect-an-autocomplete-completion)
- Markdown representation: [https://unrust.dev/use-cases/inspect-an-autocomplete-completion/index.md](https://unrust.dev/use-cases/inspect-an-autocomplete-completion/index.md)

Published: 2026-07-14

## Direct answer

Inspect an autocomplete completion before accepting it by reading the code immediately around the cursor and asking what the missing lines must guarantee. Check whether the completion creates a new value or mutation, adds a default, catches an error, or invokes an API with an assumed signature. A completion can save typing, but only the surrounding contract tells you whether its behavior is appropriate.

## Use the cursor location as evidence, not instruction

The position of a suggestion tells you where text might fit, not what the program needs. Look at the function name, types, callers, and tests around the gap, then decide whether the proposed branch, helper, or expression preserves the intended relationship between input and output.

## Inspect defaults and side effects

Short completions often introduce the most consequential decisions in a compact form: a fallback value, a mutation, a swallowed exception, or an extra request. Expand those decisions mentally and verify their behavior with a focused test instead of accepting them because the syntax looks conventional.

## Practice loop

1. Read the enclosing function and state its input-output contract before accepting a completion.
2. Identify one default, mutation, or error path implied by the suggested code.
3. Run a small test that distinguishes the suggestion from the simplest no-op alternative.

## Limits of this page

Autocomplete quality and codebase conventions vary widely, so this page cannot supply a universal accept-or-reject rule. A short unassisted check is only a snapshot and cannot distinguish a recall lapse from an unfamiliar framework, a rushed review, or a poorly framed task.

## Source context

Editorially reviewed for Unrust using public language documentation, common code-review practice, and small original examples written for this resource system.

## Related resources

- [How to Validate Copilot Suggestions](https://unrust.dev/use-cases/validate-copilot-suggestions/index.md): Validate autocomplete and Copilot suggestions by checking their contract, assumptions, and tests before a small completion becomes a hidden behavior change.
- [JavaScript Code Recall Practice for Developers](https://unrust.dev/languages/javascript/code-recall/index.md): Practice JavaScript code recall with small, useful transformations that exercise array methods, guard clauses, and value flow without treating API memorization as a test of worth.

Next step: [Take the free diagnostic](https://unrust.dev/diagnostic/index.md)