Gemini Gems Unable to Rewrite: Improve Instructions Manually

When Gemini cannot rewrite your Gem instructions, the result is usually a generic error message or an output that ignores most of what you wrote. The rewrite step is a convenience, not a requirement: you can write effective Gem instructions directly, without asking Gemini to improve them for you.

Tools like fenbs store the final approved version of instructions as Skills, outside Gemini, so a rewrite failure does not put your work at risk. See the Gemini Gems overview for context on how Gem instructions work before editing them.

What the instruction rewrite step does

Gemini offers to rewrite your Gem instructions when you create or edit a Gem. It takes the text you have written and tries to expand, restructure or clarify it. The goal is to produce instructions that the Gem will follow more consistently.

The rewrite is optional. Many well-written instructions work exactly as entered, without any rewriting. If the rewrite step fails or produces something worse than your original, skip it and use your own text.

Common reasons the rewrite fails

• The instructions are too short or too vague for Gemini to act on. A one-line description will not produce a useful rewrite.
• The instructions are already well-structured. Gemini may return them largely unchanged or with minor wording changes that make little difference.
• A network or session issue interrupted the rewrite request. Try refreshing and attempting it again.
• The instruction text is at or near the character limit, leaving little room for an expanded rewrite. Shorten the instructions and try again.

Writing instructions manually without the rewrite step

The most reliable Gem instructions are written by the person who knows the task, not generated by a general rewrite. A manual approach takes a little longer but produces instructions that match your actual needs.

Use this structure for any Gem instruction you write directly:

1. Role sentence: one sentence that says what the assistant is and who it is helping. "You are a plain-language editor working on business documents for non-technical readers."
2. Rules: three to seven specific instructions. Each one should describe an observable behavior, not a general aspiration. "Flag any sentence longer than 25 words" is specific. "Write clearly" is not.
3. Output format: the shape of what you expect back. "Return the revised text, then a numbered list of changes with one sentence of reasoning for each."
4. Scope note: one or two sentences on what the Gem should not do or should ask about before doing. "Ask me to confirm the intended audience before editing if I have not stated it."

Write each section as a plain paragraph or a short bulleted list inside the instructions field. Gemini reads both formats. Headings are optional but help when the instructions cover multiple behaviors.

Testing the instructions before saving them as final

Before saving a version of the instructions as permanent, test them on two or three real examples. Use examples that represent the range of work the Gem will handle: one typical case, one edge case, and one where the instructions should cause the Gem to ask a clarifying question.

If the Gem misses something it should have caught, add a more specific rule. If it asks questions it should be able to answer from the instructions, add the missing information. Do not add more than one or two rules per test round. After three rounds, the instructions are usually stable enough to save.

A worked example of manual instruction improvement

Say you started with this draft instruction: "Help me write better emails." That is too vague for a useful rewrite and will produce a Gem that does almost anything.

A manual improvement adds specificity at each level:

Help me write better emails.

You are an email editor for business correspondence.

Rules:
- Make the subject line state the main point in eight words or fewer.
- Put the key request or decision in the first two sentences of the body.
- Cut any sentence that repeats something already said.
- Flag any commitment made in the email (a deadline, a deliverable, a meeting) with [COMMITMENT].

Output: the revised email, followed by a bullet list of changes made.

The second version is testable, predictable and useful. You did not need the rewrite step to produce it. For more instruction examples, see the Gemini Gems templates guide.

Apply the same approach to any instruction that is vague. Ask yourself: if someone else read this instruction, could they predict exactly what the assistant will do in a given situation? If not, the instruction needs a more specific rule or a clearer output format. Vague instructions are not a starting point the rewrite feature can fix; they need to be made specific by the person who knows what the task actually requires.

How to do this with fenbs

1. Create a free account and open your personal kanban board.
2. Open Skills and prompts. Write the instruction directly in fenbs first, using the role-rules-format-scope structure above.
3. Copy the finished text into the Gemini Gems editor. Save it without using the rewrite step.
4. Test the Gem on three examples. Return to fenbs to update the Skill if you change the instructions.
5. Connect a supported AI app via Integrations to use the same Skill in other tools.

fenbs does not connect to Gemini directly over MCP. For Gemini sessions, paste the Skill text into the Gem editor manually. The ai-prompts topic hub has more on building effective reusable instructions.