DoorDash Engineering · Cloud Agents Platform
Flux hands tasks to secure, autonomous coding agents — so engineers can focus on innovation, critical thinking, and the complex problems that actually need a human.
Flux at work
Unattended. In parallel. Around the clock.
Why Flux exists
Hosted coding agents force a choice. Send sensitive code and context out to a third party — or open a path from that third party back into your internal systems. Flux was built in-house so DoorDash engineers never have to pick.
Send sensitive code & context to a third party
Open a path from that third party back into internal systems
DoorDash built Flux in-house instead. Neither tradeoff accepted.
The harder problem wasn't getting an agent to write code — it was giving the agent the right environment, tools, permissions, integrations, and constraints.
The platform
Sandboxes, an MCP gateway, playbooks, invocation surfaces. Composable primitives — so teams build new agent workflows without reworking infrastructure.
work delivered — reviews posted, PRs opened, every step logged
Every task runs inside a hardware-level-isolated microVM, provisioned with exactly the repositories, developer tools, secrets, and runtime dependencies the task requires. One session can carry changes across multiple repositories — and open multiple pull requests.
Agent Gateway — DoorDash's in-house MCP gateway. Each playbook declares the tools it requires, and Flux grants only the scoped permissions needed. Every action is logged for audit, and the gateway is the centralized control point for authentication, authorization, observability, usage tracking, and policy enforcement.
A playbook is a reusable unit of agentic work defined in a single YAML file — task, inputs, context, skills, tools, permissions, validation, expected outputs, and safety boundaries, packaged together. Agentic steps bring flexibility and judgment; deterministic steps bring predictability, lower cost, and easier validation.
Slack for collaborative delegation. GitHub for PR and CI automation. Cron for recurring maintenance. The CLI for direct developer control. And a conversational skill, for when typing a sentence is faster than typing a command.
See the surfaces in actionInvocation surfaces
One playbook — code-review — invocable five ways. Pick a surface; the delegation underneath doesn't change.
@Flux — review PR 4821 when you get a sec
Delegated — code-review playbook · sandbox provisioned · scoped tools granted.
Review posted to the PR ✓ full trace in the audit log.
collaborative delegation — in the open, where the team can see it
Summary posted — findings, risk notes, and suggested follow-ups. Every action logged.
PR & CI automation — right on the work itself
# recurring maintenance, on a schedule
0 * * * * flux run code-review
0 6 * * 1 flux run code-reviewrecurring maintenance — unattended, around the clock
$ flux run code-review --pr 4821
▸ sandbox firecracker microVM · repos + tools provisioned
▸ gateway declared tools → scoped access granted
▸ steps agentic review + deterministic checks
✓ review posted · every action loggeddirect developer control — when you want your hands on it
Review the open PRs on my team's board and summarize the risky ones.
Running code-review across the board — summaries will land in the PR threads; risky changes flagged first.
Done ✓ two flagged for human judgment. Trace in the audit log.
a conversational skill — a sentence instead of a command
Lessons learned
Automated code review went first — it's frequent, measurable, and easy to evaluate. The trust earned there unlocked CI triage, on-call support, recurring maintenance, and ticket-driven development.
Public Slack threads beat private channels. When engineers can watch agents work, delegation stops being an act of faith — and adoption follows.
A playbook library doesn't adopt itself. Workshops and hackathons turned playbooks from a platform feature into an engineering habit.
What's next
The source
Flux — the sandboxes, the gateway, the playbooks, the surfaces — is documented in the DoorDash Tech Blog announcement that inspired this page.
Read the announcementOriginal announcement figures
DoorDash Tech Blog · August 11, 2026
Santosh Banda
Jeffrey Hwang
Siddarth Kodwani
/flux run code-review