# Engineering playbook

URL: /workflows/engineering/playbook · Id: `page:workflows/engineering/playbook`

> How the Engineering Team turns definitions into running Interfaces, ships by traffic share, restores service first, and keeps one record of code.

The [Engineering Team](/agents/engineering) turns definitions into running [Interfaces](/business/nouns/interface) and keeps them up. Its week is a stream of small [Changes](/business/nouns/change), each shipped by traffic share and reverted on any guardrail breach.

## From definition to Version
The [Engineering Lead](/agents/engineering/engineering-lead) receives one [Issue](/business/nouns/issue) a day from [Daily ship](/workflows/processes/shipping/daily-ship) and implements it as one Change. A Change is a proposed set of writes, previewed on its own branch against test records. Nothing it does in preview touches a live [Customer](/business/nouns/customer) or moves real money.

[Change verdict](/code/verification/change-verdict) runs every check on the preview and records the verdict. A pass starts [Release a change](/workflows/processes/release/release-change), which merges the Change into a new [Version](/business/nouns/version). A fail returns the Change to its author with the failing run attached.

Every [Verb](/business/nouns/verb) ships on the API, CLI, MCP and SDK at once, because all four generate from one definition. A Verb missing from one Interface is a defect, not a backlog item. [Agents](/business/nouns/agent) and [Humans](/business/nouns/human) reach the same Verbs under the same names.

## Ship by traffic share
Each Version deploys to 1% of traffic, then 10%, 50% and all. At each step the deploy watches its guardrail [Metrics](/business/nouns/metric): error rate, p95 latency and the one Metric that matters now. A breach at any step reverts the deploy without waiting for anyone.

Take a [Headless SaaS](/products/templates/headless-saas) that sends appointment reminders for clinics. A Change batches sends to cut cost per message. At 1% of traffic the error rate climbs from 0.2% to 3%, and the deploy reverts before the 10% step.

The cause turns out to be one carrier rejecting batches over 50 messages. The fix caps batch size, passes its verdict, and reaches all traffic by noon.

## One record for code
Code and definitions live in Repositories, in [db.sb](/code/platform/db-sb): branches, Changes, checks and Versions in the same database as every other record. Builds and generated code run in isolated Sandboxes, leased per job.

A repository is db-first or git-first. In a db-first repository, GitHub holds a regenerable copy; in a git-first one, edits are authored in GitHub and imported into db.sb as Changes. Either way db.sb is the record, and every Change passes the same verdict.

## Incidents
An [Incident](/business/nouns/incident) is a failure Customers feel in production. When one opens, [Resolve an incident](/workflows/processes/incident-response/resolve-incident) posts it to the status page within 5 minutes. The [Reliability Engineer](/agents/engineering/reliability-engineer) restores service first, reverting the last Change when it is the cause.

The cause gets fixed second, in a new Change. The postmortem links the Change that prevents a repeat, and the Incident closes with the status page updated.

Take an [Agent as a Service](/products/templates/agent-as-a-service) that drafts lease summaries for property managers. After a Version deploys, latency on its MCP server triples. The Incident is public in 4 minutes, the revert lands in 9, and the fix ships the next morning.

## Wiring and access
Each new [Startup](/business/nouns/startup) starts [Connect providers](/systems/integrations/provider-wiring/connect-providers). The [Integration Engineer](/agents/engineering/integration-engineer) lists the [Capabilities](/business/nouns/capability) the Startup’s [Products](/business/nouns/product) use and wires the default upstream for each. It runs one test call per [Integration](/business/nouns/integration) and records a fallback.

Every night the [Access review](/workflows/processes/security/access-review) compares each [Role](/business/nouns/role)’s [Permissions](/business/nouns/permission) with the Verbs it called in the last 30 days. The [Security Engineer](/agents/engineering/security-engineer) removes unused Permissions and rotates secrets older than 90 days. It refuses any widening that carries no [Decision](/business/nouns/decision).

## Handoffs
| From | To | What passes |
| --- | --- | --- |
| [Product Lead](/agents/product/product-lead) | Engineering Lead | The day’s top Issue |
| Engineering Lead | [Tester](/agents/quality/tester) | Each Change, for its verdict |
| Engineering Lead | Reliability Engineer | Each Version as it ships |
| Reliability Engineer | [Operations Lead](/agents/operations/operations-lead) | Customer impact during an Incident |
| Security Engineer | [Compliance Officer](/agents/legal/compliance-officer) | Access [Evidence](/business/nouns/evidence), every month |

## Next
- [Engineering Team](/agents/engineering): Roles, [Processes](/business/nouns/process) and Metrics.
- [Quality playbook](/workflows/quality/playbook): how a Change earns its verdict.
- [Rhythm](/workflows/rhythm): every [Workflow](/business/nouns/workflow) by when it runs.