TCREI
Task · Context · References · Evaluate · Iterate — Google’s framework, and the only common one that treats prompting as a loop rather than a single message.
Use it for
Prompts you will run more than once, and any task where you have examples of good output. References is the few-shot slot; Evaluate and Iterate are what you do after reading the answer.
Avoid it for
Genuinely throwaway questions. The last two steps only pay off if you are going to reuse or refine the prompt.
The slots
Each letter is a question the prompt has to answer.Task
What should it do?
Google teaches a strong action verb plus the deliverable — draft, summarise, compare, rewrite.
Example: Draft three subject lines for a webinar invitation about EU AI Act compliance.
Context
Who, why, and in what form?
Google folds audience, purpose and desired format together here.
Example: Audience is Dutch compliance officers at companies of 50–500 people. They get a lot of vendor email. Each line under 55 characters, no exclamation marks.
References Optional
What does good look like?
Paste two or three real examples, or source material. Showing beats describing — this is the slot most people skip and most regret skipping.
Example: Our best performers were: "Your AI inventory is due in 90 days" and "Article 50 in plain Dutch".
Evaluate Optional process step
Did it actually do the job?
A step you perform, not text you send. Check the output against the task: is anything factually wrong, tonally off, or simply missing?
Iterate Optional process step
What one change would fix it?
Change one slot at a time and re-run, so you learn which slot was doing the work. Google calls this mindset "always be iterating".
Strengths
- References makes few-shot prompting a habit rather than an advanced trick.
- Naming Evaluate and Iterate as steps is honest about how prompting actually works.
- Taught by Google itself, so it lines up with Gemini’s documented behaviour.
Weaknesses
- Only the first three letters go into the prompt; the last two are process, which confuses newcomers.
- No format or tone slot — both have to be folded into Context.
- No role slot, which some tasks genuinely benefit from.
Sources and grounding
- 1Google Prompting EssentialsGoogle (via Coursera)Google’s official course; its stated outcome is to "apply the prompting framework (task, context, references, evaluate, iterate)".
- 2Prompt design strategiesGoogle (Gemini API docs)The developer-facing counterpart, including few-shot guidance.