> ## Documentation Index > Fetch the complete documentation index at: https://fireworks.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # System One decisions API > Send a state and a set of typed questions to POST /inference/v1/systemone and get a calibrated probability distribution for every question in one pass. The System One decisions API takes a **state** (any text or JSON describing the current situation) and a set of typed **questions**, and returns a calibrated probability distribution for every question. The model reads the state once and answers every question from that single pass, so adding questions to a request is much cheaper than making separate calls. The same API is also available in an OpenAI-compatible shape at [`POST /inference/v1/decisions`](https://fireworks.ai/docs/api-reference/post-decisions). ## Endpoint ``` POST https://api.fireworks.ai/inference/v1/systemone ``` Authenticate with your normal Fireworks API key. Set `model` to the System One model path. The public Serverless model is [`accounts/fireworks/models/rune`](https://app.fireworks.ai/models/fireworks/rune), which serves this API and the Decisions API only; chat completions and completions against it return a `400`. Other models that don't support this API also return a `400`. ## Quickstart ```bash cURL theme={null} curl https://api.fireworks.ai/inference/v1/systemone \ -H "Authorization: Bearer $FIREWORKS_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "accounts//models/", "state": { "user_request": "Add retry with exponential backoff to the payments webhook handler, and don'\''t retry on 4xx.", "last_command": "npm test -- webhooks", "test_output": "PASS handler.test.ts (4 tests)\nFAIL retry.test.ts\n x does not retry on 4xx responses\n Expected forwardEvent to be called 1 time, received 5" }, "questions": { "task_complete": { "type": "noul", "instructions": "Is the user'\''s request fully done?" }, "next_action": { "type": "choice", "instructions": "What should the agent do next?", "criteria": { "edit_code": "Change the code to fix the failing behavior", "rerun_tests": "Run the tests again without changing anything", "ask_user": "Stop and ask the user a clarifying question", "finish": "Report the task as done" } }, "risk": { "type": "score", "instructions": "How risky would it be to ship the current change as is?", "criteria": ["safe", "minor risk", "moderate risk", "high risk", "would cause an incident"] } } }' ``` ```python Python theme={null} import os import requests response = requests.post( "https://api.fireworks.ai/inference/v1/systemone", headers={"Authorization": f"Bearer {os.environ['FIREWORKS_API_KEY']}"}, json={ "model": "accounts//models/", "state": "Customer wrote: the package arrived late and damaged, I want my money back.", "questions": { "refund": { "type": "noul", "instructions": "Does the customer ask for a refund?", "criteria": {"true": "A refund is requested", "false": "No refund is requested"}, }, "tone": { "type": "choice", "instructions": "What is the customer's tone?", "criteria": {"angry": "Angry or hostile", "neutral": "Neutral", "positive": "Positive"}, }, "urgency": { "type": "score", "instructions": "How urgent is this ticket?", "criteria": ["not urgent", "somewhat urgent", "urgent", "critical"], }, }, }, ) response.raise_for_status() print(response.json()["answers"]) ``` ## Request | Field | Type | Description | | - | - | - | | `model` | string | **Required.** The System One model path, for example `accounts//models/`. | | `state` | string or object | **Required.** The situation to decide about. Strings are used as-is; objects are serialized as JSON. | | `questions` | object | **Required.** Map of your question ID to a question. Up to 256 questions per request. | ### Question types | `type` | `criteria` | Answer | | - | - | - | | `noul` | Optional object `{"true": "...", "false": "..."}` describing each side. Defaults to yes/no. | Probability that the statement is true. | | `choice` | **Required.** Object mapping each option key to a description. Up to 208 options. | The most likely option, a probability per option, and a confidence. | | `score` | **Required.** Ordered array of 2 to 10 level descriptions, lowest first. | The expected score (0 = first level), a probability per level, and a confidence. | Every question takes an `instructions` string: the question itself, in plain language. ## Response ```json theme={null} { "model": "accounts//models/", "answers": { "refund": { "type": "noul", "noul": 0.98 }, "tone": { "type": "choice", "choice": "angry", "probabilities": { "angry": 0.91, "neutral": 0.08, "positive": 0.01 }, "confidence": 0.87 }, "urgency": { "type": "score", "score": 1.7, "legend": { "0": "not urgent", "1": "somewhat urgent", "2": "urgent", "3": "critical" }, "probabilities": { "0": 0.05, "1": 0.3, "2": 0.55, "3": 0.1 }, "confidence": 0.4 } }, "usage": { "input_tokens": 212, "cached_input_tokens": 0, "output_tokens": 0 } } ``` Values above are illustrative. | Field | Description | | - | - | | `noul` | Probability, from 0 to 1, that the statement is true. | | `choice` | The key of the most likely option. | | `score` | Expected level, from 0 to the number of levels minus 1, weighted by probability. | | `probabilities` | Probability of each option key (`choice`) or level index (`score`). Sums to 1. | | `confidence` | How concentrated the distribution is: 0 when every option is equally likely, 1 when one option has all the probability. | | `legend` | For `score`, maps each level index back to its description. | | `usage` | Token usage for the request. `cached_input_tokens` counts state tokens served from the prompt cache. | ## Pricing and capacity Billing, capacity, and rate limits depend on how the model is deployed. * **Serverless.** Rune is billed per input token on [Serverless pricing](https://fireworks.ai/docs/serverless/pricing.md). Output tokens are always zero. Capacity and rate limits work the same as for other Serverless models; see [Serverless rate limits](https://fireworks.ai/docs/serverless/rate-limits.md). * **Dedicated deployment.** Usage is billed at the deployment's standard on-demand GPU rate, and capacity scales with the deployment's size and [autoscaling settings](https://fireworks.ai/docs/deployments/autoscaling.md). ## Latency and caching * **Batch your questions.** All questions in a request share one read of the state, so asking ten questions in one request is much faster and cheaper than ten requests. * **Reuse the state.** The state is cached across requests and the questions are not. Calls that send the same large state (for example a long transcript) with different questions benefit most from caching. * **Measure server time.** The `fireworks-server-processing-time` response header reports time spent on Fireworks servers. Anything above that is network. ## Limits | Limit | Value | | - | - | | Questions per request | 256 | | Options per `choice` question | 208 | | Levels per `score` question | 2 to 10 | | Context window | 256K tokens | | Question text | 16K tokens | | State size | 4 MiB | | Request body | 8 MiB | | Request duration | 5 minutes | Current support: * **Text only.** Requests with `images` return a `400`. * **No reasoning.** `reasoning_effort` other than `"none"` returns a `400`. * **Decisions only.** The model serves `/inference/v1/systemone` and `/inference/v1/decisions` only. Chat completions and completions against it return a `400`. ## Errors Errors use the standard Fireworks error body. | Status | Meaning | | - | - | | `400` | Over a limit, an unsupported field, or a model that doesn't support this API. | | `413` | Request body over 8 MiB. | | `422` | Malformed JSON, a missing required field, or an invalid question (unknown `type` or malformed `criteria`). | | `429` | Rate limited. Retry after the `Retry-After` header. | | `503` | Temporarily at capacity. Retry after the `Retry-After` header. | | `504` | The request took longer than 5 minutes. | | `502` | Upstream failure. Safe to retry. | This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.