50 Best Gemini 3.5 Flash Agent Prompts

Last updated: May 20, 2026. Read time: 7 minutes. What you’ll learn: The “Reasoning-First” prompt structure, 10 coding prompts, 10 data analysis prompts, 10 content creation prompts, and 20 multi-modal (Video/Audio) prompts.

Gemini 3.5 Flash isn’t just another chatbot. It’s an agentic model. If you ask it “Write a blog post about AI,” you are wasting its $9/M output pricing. To get your money’s worth, you need to prompt it to plan, reason, and execute.

Here are 50 prompt templates organized by use case. Treat them as starting points — adjust the CONTEXT block to your data and the OUTPUT block to your downstream tool.

The “Reasoning-First” Template

Before the prompts, use this structure. 3.5 Flash is tuned to follow this better than any other model in its class:

GOAL: [What you want]
CONTEXT: [Attached files or background]
PLAN: Mandatory. List your steps before executing.
REASONING: Explain your "Why" for any critical decision.
OUTPUT: [Specific format]

10 Coding & DevOps Prompts

  1. The Legacy Refactor: “Attached is a 5,000-line COBOL file. Plan a migration to TypeScript/Node.js. Map every variable, identify potential logic traps, and write the first 3 core modules.”
  2. The SQL Architect: “Given this messy CSV, design a 3rd-normal-form SQLite schema. Include indexes for every foreign key and a migration script.”
  3. The PR Reviewer: “Read these 10 files in the PR. Find logic bugs, security vulnerabilities, and suggest 3 performance optimizations. Think like a Staff Engineer.”
  4. The Docker Optimizer: “Analyze this Dockerfile and the associated Go source. Reduce the image size by 50% and implement a multi-stage build.”
  5. The API Bridge: “Read the Stripe API docs and the PayPal API docs. Write a wrapper class that standardizes ‘Charge’ and ‘Refund’ across both.”
  6. The Test Generator: “Read this React component. Write 10 Vitest cases covering edge cases, accessibility (Aria labels), and mobile touch events.”
  7. The Regex Master: “Create a regex that parses this weird log format. Explain the logic and provide 5 test cases that would break a simple regex.”
  8. The Documentation Sync: “Read the source code and the existing README. Update the README to reflect the new v2 API changes, including code examples.”
  9. The Security Auditor: “Scan this Python script for SQL injection and XSS. Propose a fix using parameterized queries.”
  10. The CLI Builder: “Build a CLI tool in Go that takes a folder of images and optimizes them for web. Include a progress bar and error logs.”

10 Data & Research Prompts

  1. The PDF Miner: “Read these 5 research papers. Create a comparison table of their methodologies, sample sizes, and key findings.”
  2. The Financial Analyst: “Analyze this 100-page earnings report. Find the ‘hidden’ risks mentioned in the fine print and summarize them in 3 bullets.”
  3. The Market Researcher: “Using the provided web-search grounding, find the top 5 competitors in the ‘AI Video’ space. Compare their pricing and user growth.”
  4. The Spreadsheet Cleaner: “Fix the dates and currency formats in this 10,000-row Sheet. Standardize everything to ISO-8601 and USD.”
  5. The Trend Spotter: “Read the last 30 days of these 5 RSS feeds. Identify the 3 most significant emerging trends in LLM architecture.”
  6. The Survey Analyzer: “Analyze 500 open-ended survey responses. Categorize the sentiment into 5 buckets and quote the most ‘representative’ response for each.”
  7. The Legal Aide: “Read this 50-page MSA. Highlight the indemnification clauses and the termination notice periods.”
  8. The Historical Researcher: “Compare the 1920s economic boom with the 2020s AI boom using the attached historical documents.”
  9. The Scientific Summarizer: “Explain this complex physics paper as if I am a junior dev. Use a coding analogy.”
  10. The Data Visualizer: “Suggest the 3 best chart types to represent this dataset. Provide the Mermaid.js code for each.”

10 Content & Marketing Prompts

  1. The Content Repurposer: “Take this 20-minute YouTube transcript. Turn it into: 1 deep-dive blog post, 5 Twitter threads, and 3 LinkedIn carousels.”
  2. The SEO Strategist: “Read these 3 top-ranking articles for the keyword ‘best AI tools’. Plan an article that beats them on depth, keyword density, and value.”
  3. The Voice Matcher: “Read these 5 emails I wrote. Write a new email to a partner about a 30% price hike, matching my exact tone and level of formality.”
  4. The Newsletter Architect: “Analyze my last 10 newsletters. Propose a new structure for Q3 that increases CTR based on the topics that performed best.”
  5. The Ad Copywriter: “Write 10 variants of a Facebook ad for [Product]. Use the ‘AIDA’ framework for 5 and the ‘Problem-Agitation-Solution’ for 5.”
  6. The Script Writer: “Write a 60-second TikTok script for a product demo. Include visual cues, sound effect suggestions, and a clear CTA.”
  7. The Book Outliner: “Based on this 1-sentence premise, create a 20-chapter outline. Include character arcs and a major plot twist in Chapter 12.”
  8. The Podcast Preparer: “Read this guest’s bio and their last 3 blog posts. Generate 10 ‘deep-cut’ questions that haven’t been asked in other interviews.”
  9. The Landing Page Auditor: “Read this landing page copy. Find 3 friction points and propose a rewrite that focuses on ‘Benefits’ over ‘Features’.”
  10. The Brand Voice Guide: “Analyze these 20 social media posts. Create a 1-page ‘Brand Voice Guide’ that a new freelancer could follow.”

20 Multi-modal (Video/Audio/Image) Prompts

  1. The Video Editor: “In this 10-minute video, find every time the speaker mentions ‘pricing’. Give me the exact timestamps.”
  2. The Audio Transcriber: “Transcribe this audio file. Correct any technical jargon (like ‘Kubernetes’ or ‘PyTorch’) that might be misheard.”
  3. The Image Captioner: “Describe this complex infographic in detail for a blind user. Focus on the data relationships, not just the colors.”
  4. The Scene Describer: “Watch this 30-second clip. Describe the lighting, camera angle, and the ‘vibe’ of the music.”
  5. The UI Auditor: “Look at this screenshot of my app. Find 3 accessibility issues (contrast, button size, layout) and suggest fixes.”
  6. The Hand-written Note Reader: “OCR these 10 photos of my whiteboard notes. Organize them into a structured markdown document.”
  7. The CCTV Analyst: “Watch this 5-minute security feed. Flag the moment someone enters the frame wearing a red hat.”
  8. The Sports Highlight Reel: “Watch this 1-hour game. Identify the 5 most ‘exciting’ moments based on the crowd noise and fast-paced action.”
  9. The Recipe Generator: “Look at this photo of my fridge. Propose 3 healthy recipes I can make with only these ingredients.”
  10. The Fashion Consultant: “Look at these 5 outfit photos. Which one is best for a ‘Business Casual’ tech conference? Why?”
  11. The Landscape Designer: “Look at this photo of my backyard. Sketch a 3-step plan to add a xeriscape garden.”
  12. The Product Photo Grader: “Review these 10 product shots. Which 3 have the best lighting for an Amazon listing?”
  13. The Logo Critiquer: “Look at this logo draft. Does it follow modern ‘minimalist’ design principles? What should change?”
  14. The Slide Deck Reviewer: “Read these 20 slides. Find any inconsistent fonts or alignment issues.”
  15. The Map Interpreter: “Look at this screenshot of a Google Maps area. Describe the road network, identify likely commercial vs residential zones, and estimate walkability.”
  16. The Receipt Parser: “Here are 10 photos of receipts. Extract date, vendor, total, and currency from each. Output as a CSV. Flag any photo where the total is unclear or the receipt is partially cut off.”
  17. The Blueprint Reader: “Read this architectural blueprint. Calculate the total square footage of the ‘Living Area’.”
  18. The Plant Doctor: “Look at this photo of my dying Monstera. What is the most likely cause (water, light, pests)? How do I fix it?”
  19. The Diagram Reader: “Look at this whiteboard photo of a system architecture diagram. Transcribe it into a structured component list with arrows describing the data flow, then output it as Mermaid.js code.”
  20. The Video Mood Matcher: “Watch this video and listen to this audio track. Do they match? If not, what genre of music would fit the visuals better?”

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