> ## Documentation Index > Fetch the complete documentation index at: https://braintrust.dev/docs/llms.txt > Use this file to discover all available pages before exploring further. # Manage Loop threads and limits > Rename and delete threads, understand sandbox lifecycle, and learn how Loop limits concurrent active threads. Loop threads persist, so you can leave a page and come back to the work in progress. This page covers cleaning them up, how sandboxes behave, and how many threads can be active at once. ## View thread history When you open a long thread, Loop initially loads its recent history. To view earlier messages, scroll to the top of the conversation and click **Load earlier messages** when available. Wait for Loop to finish working before loading earlier messages. ## Rename a thread On the [** Loop**](https://www.braintrust.dev/app/~/loop) page, select the menu on the thread header or on any thread in the sidebar, select **Rename thread**, enter a name of up to 256 characters, then click **Save**. ## Delete a thread On the [** Loop**](https://www.braintrust.dev/app/~/loop) page, select the menu on the thread header or on any thread in the sidebar, select **Delete thread**, then confirm. Deleting a thread is permanent and cannot be undone. You can't delete a thread while Loop is actively working in it. A thread whose sandbox has gone to sleep isn't running, so you can delete it. Automation run threads are read-only and can't be deleted this way. See [Review past runs](/docs/loop/automations#review-past-runs). ## Sandboxes Loop runs in an isolated, per-user sandbox, which is what lets it inspect trace files directly and run commands against your data. **When a sandbox starts.** Loop starts one the first time you send a message in a thread, not when you open the [** Loop**](https://www.braintrust.dev/app/~/loop) page or revisit a saved thread. **When a sandbox sleeps.** After a period without activity, the sandbox goes to sleep. Send another message in that thread and it resumes automatically, with the thread's history intact. When a sandbox reaches its maximum lifetime, Loop starts a fresh one for your next message. Your thread and its history are unaffected. A sandbox has a maximum lifetime of 8 hours, including time spent asleep. Self-hosted deployments provide their own sandboxes, so sandbox behavior depends on the capacity you provision. On AWS, enable the [Loop runtime](/docs/admin/self-hosting/configure/loop-runtime) to run Loop in your data plane. Until you do, Loop runs in the browser instead. ## Thread concurrency Braintrust-hosted Loop limits how many threads can be active at the same time. A thread counts as active while Loop is working in it and for a short idle period afterward. The limit applies separately to each member, service token, and automation within each organization. Sending another message in a thread that is already active does not consume another slot. | Organization plan | Concurrent active threads | | ------------------------------------------------- | ------------------------- | | Starter without on-demand usage | 5 | | Starter with on-demand usage, Pro, and Enterprise | 50 | Starting work in another thread while at the limit returns an HTTP 429 error. Wait for an active thread to release its slot, then try again. Existing threads and their histories are unaffected. ## Models and providers For any of [Loop's models](/docs/loop#choose-a-provider-and-model), the **Provider** setting in the model picker decides who pays for the inference: * **Braintrust.** Braintrust serves the model from its own AI providers, and usage draws down your organization's monthly [model credits](/docs/plans-and-limits#model-credits), shared with Topics. No setup is required. On the Starter plan, this option requires at least one organization owner with a work email address, or a payment method on file. See [Requirements](/docs/admin/ai-providers#requirements). * **Your configured provider.** The model runs through one of your organization's own OpenAI-compatible [AI providers](/docs/admin/ai-providers), and inference is billed to that provider. Loop remembers the selected provider for each thread and applies your most recent choice to new threads. Compatible provider types are OpenAI, Azure, Bedrock, OpenRouter, and Azure AI Gateway. Your configured provider must serve the Loop model you select. You need one of these once your model credits are exhausted. To configure a custom endpoint from Loop, click **Add provider** in the model picker, then click **New** under **Custom providers**. The form offers compatible provider types. Adding a custom endpoint does not expand Loop's supported models. To keep members off the built-in models, turn **Allow built-in models** off on the [AI providers](/docs/admin/ai-providers#manage-built-in-models) page. Loop then runs only on your organization's own providers, and **Braintrust** does not appear as a provider option. ## Privacy Threads are private to the person who created them. Loop cannot see another user's threads, and sharing a thread with a teammate is not available. By default, Braintrust logs frontend Loop interactions for product improvement and support. Loop works normally with this turned off, and self-hosted organizations have it off by default. See [Control Loop logging](/docs/admin/organizations#control-loop-logging). When you select your own provider, Loop calls the model through that AI provider, using your organization's own key. Your agreement with that provider, including any zero data retention agreement, governs the prompt and the response. [Loop automations](/docs/loop/automations) and [Patterns](/docs/observe/patterns) use the model and provider saved in each automation's configuration. See [Data handling](/docs/admin/ai-providers#data-handling). [Topics](/docs/observe/topics) is separate. Facet summarization, embeddings, and cluster naming always run on Braintrust-served models with Zero Data Retention, whatever model you pick in Loop. ## Next steps * [What Loop can do](/docs/loop/capabilities) for the full range of tasks. * [Run Loop on a schedule](/docs/loop/automations) for work that shouldn't depend on an open chat. * [Plans and limits](/docs/plans-and-limits) for the rest of the system limits.