openAgent

1# opencode database guide
2 
3## Database
4 
5- **Schema**: Drizzle schema lives in `packages/core/src/**/*.sql.ts`.
6- **Migrations**: database migrations live in `packages/core` and are applied by core.
7 
8## Development server
9 
10- Running `bun dev` from `packages/opencode` starts the live interactive TUI. Do not run it as a blocking foreground command when you need to inspect the result.
11- Start it in `tmux` instead: `tmux new-session -d -s opencode-dev 'bun dev'`.
12- Capture the current TUI output with: `tmux capture-pane -pt opencode-dev`.
13- Stop the session explicitly when done: `tmux kill-session -t opencode-dev`.
14 
15# Module shape
16 
17Do not use `export namespace Foo { ... }` for module organization. It is not
18standard ESM, it prevents tree-shaking, and it breaks Node's native TypeScript
19runner. Use flat top-level exports combined with a self-reexport at the bottom
20of the file:
21 
22```ts
23// src/foo/foo.ts
24export interface Interface { ... }
25export class Service extends Context.Service<Service, Interface>()("@opencode/Foo") {}
26export const layer = Layer.effect(Service, ...)
27export const defaultLayer = layer.pipe(...)
28 
29export * as Foo from "./foo"
30```
31 
32Consumers import the namespace projection:
33 
34```ts
35import { Foo } from "@/foo/foo"
36 
37yield * Foo.Service
38Foo.layer
39Foo.defaultLayer
40```
41 
42Namespace-private helpers stay as non-exported top-level declarations in the
43same file — they remain inaccessible to consumers (they are not projected by
44`export * as`) but are usable by the file's own code.
45 
46## When the file is an `index.ts`
47 
48If the module is `foo/index.ts` (single-namespace directory), use `"."` for
49the self-reexport source rather than `"./index"`:
50 
51```ts
52// src/foo/index.ts
53export const thing = ...
54 
55export * as Foo from "."
56```
57 
58## Multi-sibling directories
59 
60For directories with several independent modules (e.g. `src/session/`,
61`src/config/`), keep each sibling as its own file with its own self-reexport,
62and do not add a barrel `index.ts`. Consumers import the specific sibling:
63 
64```ts
65import { SessionRetry } from "@/session/retry"
66import { SessionStatus } from "@/session/status"
67```
68 
69Barrels in multi-sibling directories force every import through the barrel to
70evaluate every sibling, which defeats tree-shaking and slows module load.
71 
72# opencode Effect rules
73 
74Use these rules when writing or migrating Effect code.
75 
76See `specs/effect/migration.md` for the compact pattern reference and examples.
77 
78## Core
79 
80- Use `Effect.gen(function* () { ... })` for composition.
81- Use `Effect.fn("Domain.method")` for named/traced effects and `Effect.fnUntraced` for internal helpers.
82- `Effect.fn` / `Effect.fnUntraced` accept pipeable operators as extra arguments, so avoid unnecessary outer `.pipe()` wrappers.
83- Use `Effect.callback` for callback-based APIs.
84- Use `Effect.void` instead of `Effect.succeed(undefined)` or `Effect.succeed(void 0)`.
85- Prefer `DateTime.nowAsDate` over `new Date(yield* Clock.currentTimeMillis)` when you need a `Date`.
86 
87## Module conventions
88 
89- In `src/config`, follow the existing self-export pattern at the top of the file (for example `export * as ConfigAgent from "./agent"`) when adding a new config module.
90 
91## Schemas and errors
92 
93- Use `Schema.Class` for multi-field data.
94- Use branded schemas (`Schema.brand`) for single-value types.
95- Use `Schema.TaggedErrorClass` for typed errors.
96- Use `Schema.Defect` instead of `unknown` for defect-like causes.
97- In `Effect.gen` / `Effect.fn`, prefer `yield* new MyError(...)` over `yield* Effect.fail(new MyError(...))` for direct early-failure branches.
98 
99## Runtime vs InstanceState
100 
101- Use `makeRuntime` (from `src/effect/run-service.ts`) for all services. It returns `{ runPromise, runFork, runCallback }` backed by a shared `memoMap` that deduplicates layers.
102- Use `InstanceState` (from `src/effect/instance-state.ts`) for per-directory or per-project state that needs per-instance cleanup. It uses `ScopedCache` keyed by directory — each open project gets its own state, automatically cleaned up on disposal.
103- If two open directories should not share one copy of the service, it needs `InstanceState`.
104- Do the work directly in the `InstanceState.make` closure — `ScopedCache` handles run-once semantics. Don't add fibers, `ensure()` callbacks, or `started` flags on top.
105- Use `Effect.addFinalizer` or `Effect.acquireRelease` inside the `InstanceState.make` closure for cleanup (subscriptions, process teardown, etc.).
106- Use `Effect.forkScoped` inside the closure for background stream consumers — the fiber is interrupted when the instance is disposed.
107- To make a service's `init()` non-blocking, fork `InstanceState.get(state)` at the `init()` call site (e.g. `Effect.forkIn(scope)`), not by forking work inside the `InstanceState.make` closure. Forking inside the closure leaves state incomplete for other methods that read it.
108- `src/project/bootstrap.ts` already wraps every service `init()` in `Effect.forkDetach`, so `init()` is fire-and-forget in production. Keep `init()` methods synchronous internally; the caller controls concurrency.
109 
110## Effect v4 beta API
111 
112- `Effect.fork` and `Effect.forkDaemon` do not exist. Use `Effect.forkIn(scope)` to fork a fiber into a specific scope.
113 
114## Preferred Effect services
115 
116- In effectified services, prefer yielding existing Effect services over dropping down to ad hoc platform APIs.
117- Prefer `FileSystem.FileSystem` instead of raw `fs/promises` for effectful file I/O.
118- Prefer `ChildProcessSpawner.ChildProcessSpawner` with `ChildProcess.make(...)` instead of custom process wrappers.
119- Prefer `HttpClient.HttpClient` instead of raw `fetch`.
120- Prefer `Path.Path`, `Config`, `Clock`, and `DateTime` when those concerns are already inside Effect code.
121- For background loops or scheduled tasks, use `Effect.repeat` or `Effect.schedule` with `Effect.forkScoped` in the layer definition.
122 
123## Effect.cached for deduplication
124 
125Use `Effect.cached` when multiple concurrent callers should share a single in-flight computation rather than storing `Fiber | undefined` or `Promise | undefined` manually. See `specs/effect/migration.md` for the full pattern.
126 
127## Callback boundaries
128 
129Use `EffectBridge` for native or external callbacks (`@parcel/watcher`, `node-pty`, native `fs.watch`, plugin callbacks, etc.) that need to re-enter Effect services with instance/workspace context.
130 
131Plain async code should pass explicit context or stay inside an Effect fiber; do not add ambient instance context shims.
132