{"type":"post","id":"openai-s-agents-api-documentation-now-describes-pre-c3eb29","slug":"openai-s-agents-api-documentation-now-describes-pre-c3eb29","title":"OpenAI’s Agents API documentation now describes pre-warmed OpenAI-hosted sandboxes","description":"Thesis: Pre-warming makes environment readiness a separate stage in the agent workflow, rather than work that must begin only after a user request arrives.","retrieval_nugget":"Thesis: Pre-warming makes environment readiness a separate stage in the agent workflow, rather than work that must begin only after a user request arrives.","published_at":"2026-10-20","updated_at":"2026-10-20","record_date":"2026-10-20","date_kind":"published_at","topics":["sandbox","agents","agent-runtime"],"source_urls":["https://developers.openai.com/api/docs/guides/agents-api/environments/prewarmed"],"schema_version":"newruntime-agent-readable-v0.2","stable_id":"post:openai-s-agents-api-documentation-now-describes-pre-c3eb29","status":"published","visuals":[],"editorial_provenance":{"schema_version":"newruntime-editorial-copy-v1","content_status":"source_grounded_final","final_copy_sha256":"sha256:6e0132a4aeea04f7e5ef3e11eaed57958d9473a1d0fc9818f504a5cfedcdd10f","reviewed_at":"2026-10-20T20:08:49.240Z","source_evidence_count":1,"verified_claim_count":3,"site_analysis_schema_version":"newruntime-site-analysis-v1","site_object_kind":"field_note","observed_fact_count":3,"implication_count":2,"watch_condition_count":1,"related_record_count":0},"analysis":{"schema_version":"newruntime-site-analysis-v1","object_kind":"field_note","thesis":"Pre-warming makes environment readiness a separate stage in the agent workflow, rather than work that must begin only after a user request arrives.","observed_facts":[{"text":"OpenAI’s documentation says a developer can create an OpenAI-hosted environment, install packages, load files, and run setup commands before creating an Agents API session.","source_urls":["https://developers.openai.com/api/docs/guides/agents-api/environments/prewarmed"]},{"text":"The documentation says an environment can be attached after reaching ready, or while setup is still running, with agent access deferred until setup completes.","source_urls":["https://developers.openai.com/api/docs/guides/agents-api/environments/prewarmed"]},{"text":"Pre-warming is free before attachment, and unattached environments expire after five minutes.","source_urls":["https://developers.openai.com/api/docs/guides/agents-api/environments/prewarmed"]}],"mechanism":"The workspace and the session are separate objects. Preparing the workspace in advance can move dependency installation and other setup off the request’s critical path.","why_now":"OpenAI is documenting an explicit workflow for reducing the setup a user waits for in latency-sensitive applications, including a reporting example that prepares dependencies while a user chooses a dataset.","implications":["Teams with predictable setup can test whether asynchronous preparation makes their agent experience feel faster without paying container charges before attachment.","The five-minute expiration creates a practical constraint on how far ahead a team can prepare an environment."],"evidence_boundary":"The documentation describes the capability and example, but supplies no measured latency improvement, reliability results, or evidence that pre-warming benefits every task.","watch_conditions":["Watch for published latency measurements and clarification of how often environments are ready before attachment in production workloads."],"related_records":[],"new_branch_reason":"No prior New Runtime analytical record was supplied for this specific pre-warming capability; this note starts a distinct record about decoupling environment setup from session start."},"editor":{"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]},"routes":{"html":"https://newruntime.com/posts/openai-s-agents-api-documentation-now-describes-pre-c3eb29/","markdown":"https://newruntime.com/posts/openai-s-agents-api-documentation-now-describes-pre-c3eb29.md","json":"https://newruntime.com/posts/openai-s-agents-api-documentation-now-describes-pre-c3eb29.json"},"related_patterns":["harness-architecture-outlives-model-choice"],"next_reads":[{"type":"topic","path":"/topics/sandbox/","url":"https://newruntime.com/topics/sandbox/","title":"Sandbox","reason":"Explore the sandbox topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/sandbox.md","json_url":"https://newruntime.com/topics/sandbox.json"},{"type":"topic","path":"/topics/agents/","url":"https://newruntime.com/topics/agents/","title":"Agents","reason":"Explore the agents topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/agents.md","json_url":"https://newruntime.com/topics/agents.json"},{"type":"topic","path":"/topics/agent-runtime/","url":"https://newruntime.com/topics/agent-runtime/","title":"Agent Runtime","reason":"Explore the agent-runtime topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/agent-runtime.md","json_url":"https://newruntime.com/topics/agent-runtime.json"},{"type":"collection","path":"/posts/","url":"https://newruntime.com/posts/","title":"Field Notes","reason":"Open the latest editorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/posts.json"},{"type":"collection","path":"/source-ledger.json","url":"https://newruntime.com/source-ledger.json","title":"Source Ledger","reason":"Inspect the public source evidence graph.","media_type":"application/json"}]}