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GH-300 · Sample questions
10 real questions from the CertifyDeck GH-300 bank, spread across the domains of the official GitHub Copilot skills outline, with the correct answer and a full explanation of why the other options are wrong. They are original questions written from the public syllabus, not exam dumps, and they are the same style you will find in the practice tests and mock exams.
Correct answer: C. Single
Single asks you to focus each prompt on one well-defined task or question, and this prompt bundles three unrelated tasks. The instructions are explicit, so Specific is met, and the prompt is a single sentence, so it is not breaking Short; Surround concerns file names and open files rather than the prompt text.
Correct answer: D. Repeat the request with several sample inputs and the output expected for each
GitHub recommends giving examples of input data and expected outputs; its own guidance shows a prompt listing every date format to support plus an example call and result. The missing information is which formats exist, so a new thread or a senior-developer role still leaves Copilot guessing, and narrowing to the most common format drops requirements.
Correct answer: D. A Copilot Space shared with the team
GitHub recommends creating a Copilot Space for topics where people tend to ask similar questions, such as how authentication works: the space organizes the relevant code and documentation in one place, Copilot answers from it, and it can be shared with the team. A prompt file is tempting because it is reusable, but it stores a prompt to run, not a curated body of context. Content exclusion hides files from Copilot, and an issue per question for the cloud agent is not a reusable knowledge source.
Correct answer: D. They work from the code being written and may miss larger design issues
The application card for inline suggestions lists a limited scope: suggestions are based on the context of the code being written, so they may not identify larger design or architectural issues. They are not limited to the current line, because the prompt also includes context such as snippets from open tabs. Content exclusion only applies to paths that administrators configure; it is not a default block on any type of file.
Correct answer: C. They appear visually distinct and apply only when accepted
Inline suggestions follow human-in-the-loop principles: they are shown visually distinct from the surrounding content and are only applied to the file when the user explicitly accepts them, so no code changes happen without deliberate action. The developer can accept them fully or partly, dismiss them, or keep typing to ignore them. They are never written on save or committed to a branch automatically.
Correct answer: A. Business data is not used to train models, so the option is not shown for this plan
GitHub does not use Copilot Business or Copilot Enterprise customer data to train AI models; that data is protected under GitHub's Data Protection Agreement, so the training setting is not displayed for these plans. It is not an organization policy that hides it, and the setting lives in the personal Copilot settings on GitHub, not in the IDE. The user feedback collection option controls feedback prompts on Copilot features and has nothing to do with training.
Correct answer: D. Ask Copilot Chat to explain it, then review and test it
GitHub advises understanding suggested code before implementing it, for example by asking Copilot Chat to explain it, and then reviewing it carefully. Generating regular expressions is listed among Copilot's strengths, but that does not remove the need to validate each suggestion, and avoiding Copilot entirely gives up a documented good use case.
Correct answer: B. Use tools such as linting, code scanning and IP scanning
GitHub's best practices say to use automated tests and tooling, such as linting, code scanning and IP scanning, to add an extra layer of security and accuracy checks on Copilot's work. Opening related files improves context and suggestion relevance, but it is not a check on the output, and asking the same model to approve its own answer is not independent validation.
Correct answer: B. Run /add-dir ~/projects/shared-scripts
The /add-dir slash command adds a trusted directory at any time during an interactive session, so Copilot can work with files there. /allow-all would enable all tools, paths and URLs at once, which breaks the requirement to limit access, and --allow-all-urls concerns URL access, not file paths.
Correct answer: B. Copilot ignores existing description text; start from a blank one
Copilot does not take into account existing content in the pull request description, so the documentation recommends starting with a blank description for best results. Summaries can be generated in the description field or in a comment, and they do not depend on code review or on the number of commits.
Answer each question before opening the explanation, and write down why you discarded the other options. On GH-300, most mistakes come from choosing an option that is technically possible but does not meet every requirement in the scenario.
These 10 questions are a taste of the format, not a diagnostic. To know which domains you fail, practice by domain for free and take a timed mock exam that mirrors the official weights and duration.
Start for free, no sign-up or card. Every question includes an explanation like the ones above, and the mock exam reproduces the official GH-300 format.