If an AI step fails with this error while you are building on Activepieces Cloud, the model you picked is restricted on their side — it is not something you can fix in the flow. Switch the step to a different model; if the error persists, contact Activepieces support to find out which models your account can use.
GravityDocs
Platform
AI capabilities
All AI in agents runs through one universal AI piece with six actions, powered by Gravity's managed provider.
The six AI actions
All AI in agents runs through one capability: the universal AI piece. In the step picker it appears under the "AI & Agents" tab and offers six actions:
| Action | What it does | Typical use cases |
|---|---|---|
| Ask AI | Free-form text generation from a prompt. The workhorse action. | Writing posts, emails, replies, product descriptions, recipe cards; any “take these inputs and write X” step. |
| Summarize Text | Condenses a long text into a short one. | Digesting articles, RSS items, meeting notes, or long email threads before delivery. |
| Generate Image | Creates an image from a text prompt. | YouTube thumbnails, social post visuals, illustrations. |
| Classify Text | Assigns a text to one of a set of categories. | Routing incoming email (inquiry, complaint, spam), triaging form submissions, tagging content. |
| Extract Structured Data | Pulls typed fields out of free text. | Turning a form answer or email into fields such as role, seniority, and skills; parsing receipts or job posts. |
| Run Agent | Runs a multi-step AI agent that can reason and use tools to complete a task. | Open-ended tasks where a single prompt is not enough, such as research-and-draft flows. |
How this maps to piece slugs
| Piece | Role |
|---|---|
Universal AI piece (@activepieces/piece-ai) | Carries all six actions above on our instance. |
Cloud AI category pieces (text-ai, image-ai, utility-ai, agent) | The same actions as exported from Activepieces Cloud, split across four slugs. Accepted at publish and mapped automatically to the universal piece. |
gravity-piece-ai | Gravity's metered copy of the universal AI piece. Identical actions; every call is measured so the run can be charged in credits. The platform swaps AI steps to this piece automatically at publish and clone time. Builders never add it by hand. |
How models are provided
AI steps run through Gravity's managed AI provider (OpenRouter). Builders need no API key, and there is nothing to connect. Commercial provider pieces (OpenAI, Anthropic, Azure, and the rest of the blocked list on the Supported pieces page) cannot be used instead; open-source model hosts such as Hugging Face remain available for builders who specifically need them.
“No allowed providers are available for the selected model”
Trim what you feed the AI
The most common failed run we see: a small, fast model with an entire scraped web page dumped into its prompt. Every model has a context limit, and blowing past it does not degrade gracefully — the step errors out or returns nothing, usually only on real data, after the agent is live.
- Cut before you prompt. Pass the part the step actually needs, not the whole page, email thread, or document. Use Extract Structured Data or Summarize Text as an earlier step to boil raw content down first.
- Match the model to the load. Small models are for small, well-trimmed inputs. If a step genuinely has to read a lot of text, pick a model with a large context window — do not hope a small one copes.
- Test with worst-case input. A two-line sample proves nothing; run the step on the longest, messiest page or thread it could realistically receive.