GPT-5.5 Is Now Available on Felo Agent — Try It Free
Felo Agent adds GPT-5.5 support on day one. Build AI agents powered by OpenAI's most capable model — 1M context, stronger coding, deeper research. Free to use.
OpenAI shipped GPT-5.5 on April 23. Four days later, you can already use it inside Felo Agent — no API key, no subscription, no setup.
Pick GPT-5.5 as your model, describe what you want the agent to do, and let it run. That's the whole process.
What GPT-5.5 actually changes
This isn't a point release. The benchmarks tell a different story than the version number suggests.
A million-token context window. About 750,000 words. Enough to hold an entire codebase, a stack of research papers, or three months of meeting transcripts at once. Earlier models made you chop things up, summarize the pieces, then stitch answers back together. GPT-5.5 takes it whole.
Sharper coding. 82.7% on Terminal-Bench, which tests whether a model can ship working code in realistic scenarios, not just ace textbook problems. It reads broken code, figures out what went wrong, and rewrites it. Needs less babysitting than GPT-5.4 did.
Actual research chops. It's been used to analyze complex datasets and even contribute to mathematical proofs in combinatorics. If you're building agents that do real research, this matters.
More autonomy. You can hand GPT-5.5 a vague goal and it'll figure out the steps, handle edge cases, and work through multi-part tasks on its own. That's the whole point of an agent — you shouldn't have to micromanage it.
What this means if you're building on Felo Agent
Felo Agent is where you build AI agents in plain language. Describe the task, set the rules, and the agent takes over — competitor monitoring, content summarization, document translation, deep research, whatever you need.
The model behind your agent determines its ceiling. GPT-5.5 raises that ceiling in three ways:
It holds more in its head. The 1M context window lets your agent work through massive inputs without forgetting what came earlier. Hand it a 300-page report and ask questions — it still remembers page 5 when it reaches page 280.
It reasons through complexity. Multi-step workflows that tripped up older models run more reliably now. Research a topic, cross-reference sources, produce a structured summary — GPT-5.5 keeps the thread.
It writes better code. If your agents generate, debug, or review code, the improvement is noticeable. It grasps project structure, catches subtle bugs, and produces code that actually runs.
How to get started
Takes about 30 seconds:
- Go to felo.ai/agents
- Create a new agent (or open one you've already built)
- Select GPT-5.5 as the model
- Write your instructions in plain language — what it should do, how it should behave, what tools to use
- Run it
No API keys. No token budgets. Felo handles the plumbing.
Agent ideas worth trying
Research assistant. "Find the latest papers on [topic], summarize the findings, flag anything that contradicts current consensus." The million-token context means it can work through multiple long papers without losing the plot.
Code reviewer. "Review this PR. Flag bugs, security holes, and performance issues. Suggest fixes." The Terminal-Bench scores aren't abstract — they translate into reviews that actually catch things.
Competitive intel monitor. "Track [competitor] product updates, pricing changes, and press mentions. Weekly summary." Better reasoning means it filters signal from noise across large volumes of information.
Multilingual content adapter. "Take this English post and adapt it for Japanese and German readers — localize the examples, not just the words." Felo's multilingual core paired with GPT-5.5 handles this surprisingly well.
How GPT-5.5 stacks up against other models on Felo
Felo Agent supports multiple models. Quick comparison:
| GPT-5.5 | GPT-5.4 | DeepSeek V4-Pro | |
|---|---|---|---|
| Context window | 1M tokens | 200K tokens | 1M tokens |
| Terminal-Bench | 82.7% | ~75% | ~78% |
| Agentic tasks | Strongest | Good | Strong |
| Speed | Fast | Fast | Moderate |
| Cost on Felo | Free | Free | Free |
GPT-5.5 pulls ahead on agentic work — planning, executing, and self-correcting through multi-step tasks. For agent builders, that's the number that counts.
Different jobs still call for different models. DeepSeek V4-Pro is strong for open-ended research. GPT-5.4 handles simpler tasks without the overhead. Felo lets you pick per agent.
The free part is worth emphasizing
Using GPT-5.5 through OpenAI's API costs money, and it adds up fast at scale. On Felo Agent, it's free.
No environment variables. No SDK setup. No auth flows. Open the browser, build the agent, run it.
No coding either. Instructions are plain language. If you can write a sentence describing what you want, you can build an agent.
That puts a frontier model in the hands of people who'd never touch an API — marketers, researchers, students, small business owners.
Go build something
GPT-5.5 is live on Felo Agent now. A million tokens of context, 82.7% on Terminal-Bench, and it works with less hand-holding than anything before it. Free, configured in plain English.