HTTP Route Patterns

Current guidance for packages/opencode/src/server/routes/instance/httpapi.

Handler Shape

Use HttpApiBuilder.group(...) for normal JSON and streaming HTTP API endpoints. Yield stable services once while building the handler layer, then close over those services in endpoint implementations.

export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session", (handlers) =>
  Effect.gen(function* () {
    const session = yield* Session.Service

    return handlers.handle("list", () => session.list())
  }),
)

Use raw HttpRouter only for routes that do not fit the request/response HttpApi model, such as WebSocket upgrades or catch-all fallback routes.

Do not rebuild stable layers inside request handlers. Provide stable services at the route/layer boundary and use request-level provisioning only for request-derived context.

Error Boundaries

Expected service errors should be mapped at the handler boundary to endpoint-declared public HTTP errors. Keep one-off mappings inline. Extract small helpers when the same mapping repeats.

Generic middleware should not become a domain-error mapper. It should handle cross-cutting concerns and final unknown-defect fallback.

Public JSON errors should be explicit schema contracts declared on each endpoint or group. Built-in HttpApiError.* is fine only when its generated body is intentionally the public wire shape.

Preserve existing { name, data } error bodies until a deliberate breaking API change.

OpenAPI Compatibility

public.ts still owns SDK/OpenAPI compatibility transforms. Shrink those transforms by tightening source schemas one workaround at a time.

When an OpenAPI-visible source schema changes:

• verify the generated SDK diff is intentional
• preserve legacy compatibility unless the PR explicitly changes it
• prefer source-schema fixes over new post-processing rules

Checklist For Route PRs

• Stable services are yielded at handler-layer construction.
• Expected domain errors are translated at the route boundary.
• Endpoint/group error schemas describe the public body and status.
• Middleware does not gain new domain-specific name checks.
• Raw routes are used only when HttpApi is the wrong abstraction.