diff --git a/methods/websocket/signatureSubscribe.md b/methods/websocket/signatureSubscribe.md
new file mode 100644
index 0000000..9beabaf
--- /dev/null
+++ b/methods/websocket/signatureSubscribe.md
@@ -0,0 +1,15 @@
+# signatureSubscribe
+
+WebSocket-only. Subscribe to the status of a transaction signature. The request returns a numeric subscription id. Agave then sends `signatureNotification` notifications on the same connection.
+
+## Notification wire format
+
+The notification uses JSON-RPC 2.0 with `params.result` as the payload declared in the paired YAML and `params.subscription` as the id returned by this method.
+
+## Semantics
+
+Subscriptions are scoped to the WebSocket connection. Closing the connection cancels them. The reference handler deduplicates compatible active subscriptions and rejects new subscriptions when the node limit is reached.
+
+## Implementation notes
+
+[**Agave**](../../implementations/agave.md) implements this method in the [pinned PubSub trait](https://github.com/anza-xyz/agave/blob/6dd9d38771e46103b9680357a855804165612602/rpc/src/rpc_pubsub.rs#L138).
diff --git a/methods/websocket/signatureSubscribe.yaml b/methods/websocket/signatureSubscribe.yaml
new file mode 100644
index 0000000..d994c9b
--- /dev/null
+++ b/methods/websocket/signatureSubscribe.yaml
@@ -0,0 +1,60 @@
+name: signatureSubscribe
+status: standard
+summary: Subscribe to the status of a transaction signature.
+params:
+  - name: signature
+    required: true
+    summary: Transaction signature to watch.
+    schema: { $ref: '#/components/schemas/Signature' }
+  - name: config
+    required: false
+    summary: Commitment and received-notification options.
+    schema:
+      type: object
+      properties:
+        commitment: { $ref: '#/components/schemas/Commitment' }
+        enableReceivedNotification: { type: boolean }
+result:
+  name: subscriptionId
+  summary: Identifier for this connection's subscription.
+  schema: { $ref: '#/components/schemas/U64' }
+errors:
+  - $ref: '#/components/errors/InvalidParams'
+  - $ref: '#/components/errors/InternalError'
+examples:
+  - name: basic
+    summary: Create the subscription.
+    params:
+      - name: signature
+        value: '5NfHk6JxqzQ54zk5cYBkiM7mj9XodPFdJNbB4z8zTETSV4gTWjSQm3yYAxT9Y7DkVMwq3siB1oX7nWdTUkzHd4Wq'
+    result:
+      name: subscriptionId
+      value: 1
+notification:
+  name: signatureNotification
+  description: Notification payload sent for this subscription.
+  schema:
+    type: object
+    required: [subscription, result]
+    properties:
+      subscription: { $ref: '#/components/schemas/U64' }
+      result:
+        type: object
+        required: [context, value]
+        properties:
+          context: { $ref: '#/components/schemas/RpcResponseContext' }
+          value:
+            oneOf:
+              - type: object
+                required: [err]
+                properties:
+                  err:
+                    oneOf:
+                      - $ref: '#/components/schemas/TransactionError'
+                      - type: 'null'
+              - type: string
+                enum: [receivedSignature]
+implementations:
+  agave: { status: full }
+  cloudbreak: { status: none }
+  superbank: { status: none }
diff --git a/proposals/0051-signature-subscribe.md b/proposals/0051-signature-subscribe.md
new file mode 100644
index 0000000..9648548
--- /dev/null
+++ b/proposals/0051-signature-subscribe.md
@@ -0,0 +1,38 @@
+---
+number: 0051
+title: Add signatureSubscribe
+authors: [rpcpool]
+status: draft
+created: 2026-09-14
+reference-implementations: [https://github.com/anza-xyz/agave/blob/6dd9d38771e46103b9680357a855804165612602/rpc/src/rpc_pubsub.rs#L138]
+---
+
+# Add signatureSubscribe
+
+## Summary
+
+Add the signatureSubscribe WebSocket RPC method and its signatureNotification notification.
+
+## Motivation
+
+Agave exposes this public PubSub method. A standard method page lets clients and alternative implementations use one contract.
+
+## Specification
+
+Add the paired WebSocket method page. It defines the request, subscription id, notification name and payload, and the connection-scoped lifecycle.
+
+## Return-type impact
+
+The subscribe response is a numeric subscription id. Notifications carry the method-specific payload.
+
+## Compatibility
+
+This is additive. Agave implements it. Cloudbreak and Superbank do not currently implement WebSocket PubSub.
+
+## Reference implementation
+
+[Agave pinned handler](https://github.com/anza-xyz/agave/blob/6dd9d38771e46103b9680357a855804165612602/rpc/src/rpc_pubsub.rs#L138)
+
+## Security considerations
+
+Servers must bound active subscriptions and release them when the connection closes.
diff --git a/spec-info.yaml b/spec-info.yaml
index 892ea85..bca4391 100644
--- a/spec-info.yaml
+++ b/spec-info.yaml
@@ -1,5 +1,5 @@
 title: Solana JSON-RPC API
-version: 0.1.0
+version: 0.2.0
 license:
   name: MIT
   url: https://opensource.org/license/mit/