Phase 4 · Gemini · Level 2 · Practitioner
Hands-on: a file-anchored Gem, end to end
By the end, you'll be able to…
- Build a Gem anchored to real Fernway files and give it clear, honest instructions
- Use the Gem across a genuine multi-step task: analyse, draft, refine
- Verify the Gem's answers against its source files before acting on them
Why it matters
You've met Gemini's practitioner features one at a time. This exercise stitches them into a single workflow: build a Gem over Fernway material, then use it to get a real job done from analysis to finished draft. Doing the whole loop yourself, including catching where the Gem is wrong, is what turns a set of features into a working habit. Twenty minutes here is worth an hour of reading.
What you'll do
You'll build a file-anchored Gem for Fernway, then put it to work on a realistic task: read the sales data, spot the weak region, and draft a short plan to address it, checking the Gem's answers against the actual files at every step. It pulls together everything in this level: Gems, knowledge files, grounded answers, drafting, refining and, above all, verifying.
Everything here uses the free Gemini app and the safe Fernway sample files, so anyone with a Google account can follow along. The knowledge-file part of Gems is the piece most likely to depend on your account. If you can't attach files, the "no-Gem fallback" note in each step lets you do the same task by pasting the files into a normal chat.
Before you start
- A Google account and a browser open at gemini.google.com.
- The Fernway files downloaded: the sales spreadsheet, the meeting notes and the remote-working policy.
- About twenty quiet minutes.
Privacy note. Use the Fernway sample files, not real confidential documents, while you're learning to anchor Gems. A Gem holds its files until you remove them, so practise on safe material first. The Phase 0 privacy rules apply throughout.
The steps
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Create the Gem. In the Gemini app, open Explore Gems → New Gem. Name it "Fernway Sales Assistant". In the instructions box, give it a clear brief with an honesty rule built in:
"You are the sales assistant for Fernway, a UK company selling the Starter Plan (£49), Pro Plan (£120) and Add-on Pack (£15). Use British spelling and a warm, plain tone. Answer questions about our sales and staffing only from the files I've attached. If the answer isn't in the files, say so and tell me which file you'd need. Never invent numbers, names or dates. When I ask for a written draft, keep it under 150 words and end with one clear next step."
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Anchor it to the files. In the Knowledge section, attach the sales spreadsheet, the meeting notes and the remote-working policy, from Google Drive if you can, so the Gem always reads the latest version. Save the Gem.
No-Gem fallback: start a normal chat and paste the three files in at the top, then carry on with the same prompts.
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Ask it to analyse, and demand sources. Open a chat with your Gem and ask:
"From my attached files, which region had the weakest sales, and what stands out about the data quality? Give me three points, and for each one tell me which file it came from."
Read the answer. Does it name a region, flag the messy rows (the "Sotuh"/"Midlnads" typos, the blank cells, the row where units times price doesn't match the total), and cite a source file for each point?
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Verify against the file, on purpose. Open the sales spreadsheet yourself and check the Gem's headline claim. Is the "weakest region" really weakest, or did a typo split one region's total in two and mislead it? Finding an error here is a success; it's the whole reason you check.
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Correct the Gem if it slipped. If a typo threw it off, tell it in the chat rather than starting over:
"The rows marked 'Sotuh' are the South region misspelled, and 'Midlnads' is Midlands. Re-do the regional totals treating those as the correct regions, and tell me if that changes which region is weakest."
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Draft the action. Now use the Gem for the writing job, handing it the facts you've verified:
"Draft a short internal note to the sales team about the weakest region. Say the figures are from last month, suggest we discuss it at the next team meeting, and keep the tone constructive, not blame-y. Only use facts from the files."
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Refine at least once. Nudge the draft: "a bit warmer", "add one specific figure from the sales sheet", "shorten to three sentences". Watch it keep the good parts and change only what you flagged.
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Read the final version yourself. Check every figure and name against the files one last time. This is the moment you'd catch an error before it went to the team, so catch it now.
Checklist
Tick these off as you go:
- [ ] I built a Gem with clear instructions and an explicit "don't invent" honesty rule.
- [ ] I anchored it to the three Fernway files (from Drive if possible).
- [ ] I asked it to analyse and insisted on a source file for each point.
- [ ] I opened the sales sheet and checked its headline claim myself.
- [ ] I corrected the Gem when a typo or blank misled it.
- [ ] I asked it to draft the note using only verified facts.
- [ ] I refined the draft at least once.
- [ ] I read the final version and checked every figure and name against the files.
Self-check
Ask yourself honestly:
- Did the Gem cite its sources? If any point had no file behind it, that's exactly where an invented "fact" hides, and why the "which file" instruction earns its place.
- Did a typo fool it? The "Sotuh"/"Midlnads" trap is deliberate. If the Gem's regional totals were wrong until you flagged the typos, you've just seen why anchored isn't the same as accurate.
- Did giving it verified facts improve the draft? It should have. A Gem can only be as right as the facts you confirm and hand back to it.
- Would you send that note to the team? If not, name the gap: a wrong figure, the wrong tone, a missing detail. Being able to say what's missing is the practitioner skill this whole level builds.
Common mistakes
- Trusting the anchor. A Gem answers from your files but can still misread them: a typo, a blank, a merged region. Always check the headline claim against the actual file before you act.
- Skipping the source-file step. Without "tell me which file", you can't verify anything, and unsourced points are where fabrication lives. Make the Gem show its working every time.
- Correcting by starting over. When the Gem slips, fix it in the same chat so it keeps the context. A fresh Gem or chat throws away everything that was already right.
- Over-trusting a fluent draft. The final note will read well whether or not its numbers are right. Fluent is not correct, and the read-it-against-the-files step is what keeps a wrong figure off the team's desk.
- Leaving real confidential files in a Gem. A Gem keeps its knowledge files until you remove them. Practise on the Fernway samples, and think carefully before anchoring a Gem to sensitive documents, and check what your organisation allows.
Keeping current
The workflow you just ran (build, anchor, analyse, verify, correct, draft, refine, read) is durable and works in any capable assistant, even as Gems and the in-app features change. When the screen differs from these steps, trust it and check Google's Use Gems in Gemini Apps and Gemini Apps updates. Accurate as of 13 July 2026.