> ## Documentation Index > Fetch the complete documentation index at: https://docs.blackbox.ai/llms.txt > Use this file to discover all available pages before exploring further. # Continue Task > Send a follow-up prompt to an existing task, creating a new agent run on the same chat thread with full conversation history. This endpoint continues an existing task by spawning a new agent run on the same chat thread (`chatId`). The agent receives the full conversation history as context and picks up where the previous run left off. If the original task worked on a GitHub repository, the agent will continue from the branch it created. ## Authentication To use this API, you need a BLACKBOX API Key. Follow these steps to get your API key: 1. Go to [app.blackbox.ai/agent-api](https://app.blackbox.ai/agent-api) and click **Get an API Key** (requires a Pro subscription) 2. Once provisioning completes, you will be redirected to your [Dashboard](https://app.blackbox.ai/dashboard) 3. From the Dashboard, create an API key to use with all Agent API requests Your API key will be in the format: `sk-xxxxxxxxxxxxxxxxxxxxxx` ## GitHub Connection Required **For GitHub-related tasks**: If the original task worked on a repository, the agent will automatically continue from the branch it created. Make sure your GitHub token is still stored via `POST /api/v1/git/config` — see [Store GitHub Token](/api-reference/v1/git-config-set) for details. ## Headers API Key of the form `Bearer `. Example: `Bearer sk_b41b647ffbfed27f616560` Must be set to `application/json`. ## Path Parameters The `runId` of the previous task run to continue from. Example: `a1b2c3d4-e5f6-7890-abcd-ef1234567890` ## Request Body The follow-up instruction for the agent. The agent will receive the full prior conversation as context. Examples: * `"Now add unit tests for the new module"` * `"The webhook handler is missing error handling, please fix it"` * `"Summarize what was done so far"` Override the model for this follow-up run. **If you set `model`, you must also set `agent`** (see the inheritance rule below). Omit both to keep the original run's model. Example: `"blackboxai/anthropic/claude-opus-4.7"` — see [Models](/api-reference/v1/models) for all available IDs. Explicit [agent runtime](/api-reference/v1/agent-runtimes) for this turn — `"claude"` or `"codex"`. Required whenever you change `model` (or otherwise override the runtime). Omit — together with `model` — to inherit the original run's runtime. **Runtime inheritance rule.** Continuation is designed so a plain follow-up "just continues" on the same setup: * **Neither `model` nor `agent` specified** → the follow-up inherits the **original run's model *and* agent runtime** (even an explicit codex+opus override is preserved). * **`model` and/or `agent` specified** → you are overriding, so **`agent` is required**. This prevents a model swap from silently flipping the runtime. Omitting `agent` while setting `model` returns `400`. Example — continue on Codex with an Opus model: `{ "prompt": "...", "model": "blackboxai/anthropic/claude-opus-4.7", "agent": "codex" }`. ## Response Fields Unique identifier for the new agent run. Use this to poll status or stream logs. ID of the assistant message being generated for this follow-up. UUID of the shared chat thread (same as the original task's `chatId`). The `runId` of the task that was continued (the path parameter). ## How Continuation Works 1. **Context restored** — The agent loads the full message history from the shared `chatId` 2. **GitHub context restored** — If the original task had a repo, the agent continues from the branch it created (`githubCreatedBranch`) 3. **New run created** — A fresh agent run is spawned with the follow-up prompt appended to the conversation 4. **New `runId` returned** — Use the new `runId` to track this follow-up independently ```bash cURL theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} curl -X POST 'https://agent.blackbox.ai/api/v1/tasks/a1b2c3d4-e5f6-7890-abcd-ef1234567890/continue' \ -H 'Authorization: Bearer YOUR_API_KEY' \ -H 'Content-Type: application/json' \ -d '{ "prompt": "Now add unit tests for the new payment module" }' ``` ```bash cURL - Override Model theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} curl -X POST 'https://agent.blackbox.ai/api/v1/tasks/a1b2c3d4-e5f6-7890-abcd-ef1234567890/continue' \ -H 'Authorization: Bearer YOUR_API_KEY' \ -H 'Content-Type: application/json' \ -d '{ "prompt": "Refactor the authentication logic to use middleware", "model": "blackboxai/anthropic/claude-opus-4.7" }' ``` ```javascript Node.js theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} const API_KEY = "YOUR_API_KEY"; const PREVIOUS_RUN_ID = "a1b2c3d4-e5f6-7890-abcd-ef1234567890"; const response = await fetch( `https://agent.blackbox.ai/api/v1/tasks/${PREVIOUS_RUN_ID}/continue`, { method: "POST", headers: { Authorization: `Bearer ${API_KEY}`, "Content-Type": "application/json", }, body: JSON.stringify({ prompt: "Now add unit tests for the new payment module", }), } ); const data = await response.json(); console.log(`New runId: ${data.runId}`); console.log(`ChatId: ${data.chatId}`); // Poll the new run for completion const DONE = ["completed", "failed", "cancelled", "interrupted"]; while (true) { const statusRes = await fetch( `https://agent.blackbox.ai/api/v1/tasks/${data.runId}/status`, { headers: { Authorization: `Bearer ${API_KEY}` } } ); const s = await statusRes.json(); console.log(`${s.status} — ${s.progress}%`); if (DONE.includes(s.status)) break; await new Promise(r => setTimeout(r, 3000)); } ``` ```python Python theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} import requests import time API_KEY = "YOUR_API_KEY" PREVIOUS_RUN_ID = "a1b2c3d4-e5f6-7890-abcd-ef1234567890" headers = { "Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json", } # Continue the task response = requests.post( f"https://agent.blackbox.ai/api/v1/tasks/{PREVIOUS_RUN_ID}/continue", headers=headers, json={"prompt": "Now add unit tests for the new payment module"}, ) data = response.json() new_run_id = data["runId"] print(f"New runId: {new_run_id}") # Poll until done DONE = {"completed", "failed", "cancelled", "interrupted"} while True: s = requests.get( f"https://agent.blackbox.ai/api/v1/tasks/{new_run_id}/status", headers={"Authorization": f"Bearer {API_KEY}"}, ).json() print(f"{s['status']} — {s['progress']}%") if s["status"] in DONE: break time.sleep(3) ``` ```go Go theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} package main import ( "bytes" "encoding/json" "fmt" "io" "net/http" ) func main() { apiKey := "YOUR_API_KEY" previousRunId := "a1b2c3d4-e5f6-7890-abcd-ef1234567890" url := fmt.Sprintf("https://agent.blackbox.ai/api/v1/tasks/%s/continue", previousRunId) body, _ := json.Marshal(map[string]string{ "prompt": "Now add unit tests for the new payment module", }) req, _ := http.NewRequest("POST", url, bytes.NewBuffer(body)) req.Header.Set("Authorization", "Bearer "+apiKey) req.Header.Set("Content-Type", "application/json") client := &http.Client{} resp, _ := client.Do(req) defer resp.Body.Close() respBody, _ := io.ReadAll(resp.Body) fmt.Println(string(respBody)) } ``` ```json Success Response theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} { "runId": "c3d4e5f6-a7b8-9012-cdef-123456789012", "assistantMessageId": "msg_new_run_abc123", "chatId": "chat_def789ghi012", "previousRunId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890" } ``` ```json Error - Task Not Found theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} { "error": "Task not found" } ``` ```json Error - Missing Prompt theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} { "error": "prompt: prompt is required" } ``` ```json Error - Pro Required theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}} { "error": "Claude Agent requires a Pro subscription. Please upgrade at https://www.blackbox.ai/pricing" } ``` ## Error Codes | Status Code | Error | Description | | ----------- | --------------------- | --------------------------------------------------------------------------------- | | 200 | Success | Follow-up run started successfully | | 400 | Bad Request | Missing `prompt` or invalid JSON | | 401 | Unauthorized | Invalid or missing API key | | 403 | Forbidden | Pro subscription required, task belongs to another user, or no API key configured | | 404 | Not Found | Previous task not found | | 500 | Internal Server Error | Failed to spawn agent |