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Built for real engineering decisions

AI Model & API Guides

Source-linked guidance for AI models, API integration, and developer workflows—turning fast-changing prices, quotas, capabilities, and limits into decisions you can verify.
  • Primary sources first
  • Reproducible steps and failure boundaries
  • Volatile facts carry review dates
  • 482 articles
  • 6 languages
  • 12 topics
  • Updated Oct 6, 2026

An agent execution guard checks repeated calls and operation records before allowing a tool to run.
LatestAPI Guides

How to Stop an AI Agent Tool Loop—and Keep It Stopped

Stop new tool execution, preserve verified results, and reconcile any uncertain write before resuming. A turn limit contains a loop; progress checks and operation records make recovery safer.

12 min
Codex token-exchange 403: read the full error, preserve response details, distinguish an unexplained refusal from a country, account or workspace restriction, and check the actual Codex host
Developer Tools & Agents

Codex Token Exchange Failed 403: Diagnose and Recover Sign-In

A Codex token-exchange 403 is a refused authentication request. The full error tells you whether to repair callback access, check the client’s network, renew stored credentials, or stop for an access restriction.

11 min
Nano Banana Pro troubleshooting across Gemini Apps, AI Mode and the Gemini API
Troubleshooting

Nano Banana Pro `RESTRICTED by System Instructions`? Check the Gate First

If Pro returns a restriction message or no image, first recover the correct Pro route: More → Redo with Pro in Gemini, the Pro menu in eligible AI Mode accounts, or gemini-3-pro-image in the API. Then check the actual response before calling the failure a policy block.

10 min
Nano Banana Pro image-reference troubleshooting across native Gemini, compatibility and cloud requests
Troubleshooting

Nano Banana Pro "Unsupported File URI Type"? Fix the Gemini File Route

For "Unsupported file URI type," check the exact image value your app sent and the endpoint that rejected it. Native Gemini can accept supported HTTPS URLs; local paths, unresolved templates and base64 data URLs need a different payload. Verify the repair by getting an edited image from the same Pro request.

11 min