From f684ddc62fdaf3f3b5718cd5be32c5ac5051b507 Mon Sep 17 00:00:00 2001
From: Harry Solovay <harrysolovay@gmail.com>
Date: Tue, 17 Feb 2026 08:07:58 -0500
Subject: [PATCH 1/3] feat(atom): allow custom runtime factories

---
 packages/atom/src/AtomHttpApi.ts | 4 +++-
 packages/atom/src/AtomRpc.ts     | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/atom/src/AtomHttpApi.ts b/packages/atom/src/AtomHttpApi.ts
index a58f1d0..cb622d9 100644
--- a/packages/atom/src/AtomHttpApi.ts
+++ b/packages/atom/src/AtomHttpApi.ts
@@ -161,6 +161,7 @@ export const Tag =
         | ((effect: Effect.Effect<unknown, unknown>) => Effect.Effect<unknown, unknown>)
         | undefined
       readonly baseUrl?: URL | string | undefined
+      readonly runtime?: Atom.RuntimeFactory | undefined
     }
   ): AtomHttpApiClient<Self, Id, Groups, ApiE, E> => {
     const self: Mutable<AtomHttpApiClient<Self, Id, Groups, ApiE, E>> = Context.Tag(id)<
@@ -172,7 +173,8 @@ export const Tag =
       self,
       HttpApiClient.make(options.api, options)
     ).pipe(Layer.provide(options.httpClient)) as Layer.Layer<Self, E>
-    self.runtime = Atom.runtime(self.layer)
+    const runtimeFactory = options.runtime ?? Atom.runtime
+    self.runtime = runtimeFactory(self.layer)
 
     const mutationFamily = Atom.family(({ endpoint, group, withResponse }: MutationKey) =>
       self.runtime.fn<{
diff --git a/packages/atom/src/AtomRpc.ts b/packages/atom/src/AtomRpc.ts
index 91c2ad9..bbec106 100644
--- a/packages/atom/src/AtomRpc.ts
+++ b/packages/atom/src/AtomRpc.ts
@@ -118,6 +118,7 @@ export const Tag = <Self>() =>
     readonly generateRequestId?: (() => RequestId) | undefined
     readonly disableTracing?: boolean | undefined
     readonly makeEffect?: Effect.Effect<RpcClient.RpcClient.Flat<Rpcs, RpcClientError>, never, RM> | undefined
+    readonly runtime?: Atom.RuntimeFactory | undefined
   }
 ): AtomRpcClient<Self, Id, Rpcs, ER> => {
   const self: Mutable<AtomRpcClient<Self, Id, Rpcs, ER>> = Context.Tag(id)<
@@ -133,7 +134,8 @@ export const Tag = <Self>() =>
         flatten: true
       }) as Effect.Effect<RpcClient.RpcClient.Flat<Rpcs, RpcClientError>, never, RM>
   ).pipe(Layer.provide(options.protocol))
-  self.runtime = Atom.runtime(self.layer)
+  const runtimeFactory = options.runtime ?? Atom.runtime
+  self.runtime = runtimeFactory(self.layer)
 
   self.mutation = Atom.family(<Tag extends Rpc.Tag<Rpcs>>(tag: Tag) =>
     self.runtime.fn<{

From 978cf8048b99a74e1611e88dcb875c3702dc7651 Mon Sep 17 00:00:00 2001
From: Harry Solovay <harrysolovay@gmail.com>
Date: Tue, 17 Feb 2026 14:56:22 -0500
Subject: [PATCH 2/3] add changeset

---
 .changeset/soft-spiders-care.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/soft-spiders-care.md

diff --git a/.changeset/soft-spiders-care.md b/.changeset/soft-spiders-care.md
new file mode 100644
index 0000000..600e13e
--- /dev/null
+++ b/.changeset/soft-spiders-care.md
@@ -0,0 +1,5 @@
+---
+"@effect-atom/atom": minor
+---
+
+allow overriding AtomHttpApi & AtomRpc runtime factory

From 2dbbffbc122496f01b7065a52fa94aa69ccad675 Mon Sep 17 00:00:00 2001
From: Tim Smart <hello@timsmart.co>
Date: Wed, 18 Feb 2026 09:52:19 +1300
Subject: [PATCH 3/3] docs

---
 docs/atom/AtomHttpApi.ts.md | 1 +
 docs/atom/AtomRpc.ts.md     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/docs/atom/AtomHttpApi.ts.md b/docs/atom/AtomHttpApi.ts.md
index 0c04b3c..3e73e47 100644
--- a/docs/atom/AtomHttpApi.ts.md
+++ b/docs/atom/AtomHttpApi.ts.md
@@ -49,6 +49,7 @@ export declare const Tag: <Self>() => <
       | ((effect: Effect.Effect<unknown, unknown>) => Effect.Effect<unknown, unknown>)
       | undefined
     readonly baseUrl?: URL | string | undefined
+    readonly runtime?: Atom.RuntimeFactory | undefined
   }
 ) => AtomHttpApiClient<Self, Id, Groups, ApiE, E>
 ```
diff --git a/docs/atom/AtomRpc.ts.md b/docs/atom/AtomRpc.ts.md
index 06d654e..375540c 100644
--- a/docs/atom/AtomRpc.ts.md
+++ b/docs/atom/AtomRpc.ts.md
@@ -41,6 +41,7 @@ export declare const Tag: <Self>() => <
     readonly generateRequestId?: (() => RequestId) | undefined
     readonly disableTracing?: boolean | undefined
     readonly makeEffect?: Effect.Effect<RpcClient.RpcClient.Flat<Rpcs, RpcClientError>, never, RM> | undefined
+    readonly runtime?: Atom.RuntimeFactory | undefined
   }
 ) => AtomRpcClient<Self, Id, Rpcs, ER>
 ```