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Merged
jamadeo merged 5 commits into from
Apr 2, 2026
Merged

rust acp client for extension methods #8227

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e32d543
rust client example
jamadeo Mar 30, 2026
1c20ff1
Deduplicate
jamadeo Mar 31, 2026
6151b81
regenerate schema
jamadeo Mar 31, 2026
0f7bcfe
Extract goose-sdk crate for external ACP clients
jamadeo Apr 2, 2026
b1e0dfc
Move tokio deps to dev-dependencies in goose-sdk
jamadeo Apr 2, 2026
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81 changes: 46 additions & 35 deletions crates/goose-acp-macros/src/lib.rs
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Original file line number Diff line number Diff line change
@@ -1,16 +1,20 @@
use proc_macro::TokenStream;
use quote::quote;
use syn::{
parse_macro_input, FnArg, GenericArgument, ImplItem, ItemImpl, Lit, Pat, PathArguments,
ReturnType, Type,
parse_macro_input, FnArg, GenericArgument, ImplItem, ItemImpl, Pat, PathArguments, ReturnType,
Type,
};

/// Marks an impl block as containing `#[custom_method("...")]`-annotated handlers.
/// Marks an impl block as containing `#[custom_method(RequestType)]`-annotated handlers.
///
/// The request type must derive `sacp::JsonRpcRequest` with a `#[request(method = "...")]`
/// attribute — the method name is extracted from that type at compile time, eliminating
/// duplication between the request struct and the handler.
///
/// Generates two methods on the impl:
///
/// 1. `handle_custom_request` — a dispatcher that:
/// - Uses each annotation string as the method name (include `_goose/` for goose-only methods)
/// - Uses `<RequestType as sacp::JsonRpcMessage>::matches_method` to match incoming methods
/// - Parses JSON params into the handler's typed parameter (if any)
/// - Serializes the handler's return value to JSON
///
Expand All @@ -25,11 +29,11 @@ use syn::{
///
/// ```ignore
/// // No params — called for requests with no/empty params
/// #[custom_method("session/list")]
/// async fn on_list_sessions(&self) -> Result<ListSessionsResponse, sacp::Error> { .. }
/// #[custom_method(GetExtensionsRequest)]
/// async fn on_get_extensions(&self) -> Result<GetExtensionsResponse, sacp::Error> { .. }
///
/// // Typed params — JSON params auto-deserialized
/// #[custom_method("session/get")]
/// #[custom_method(GetSessionRequest)]
/// async fn on_get_session(&self, req: GetSessionRequest) -> Result<GetSessionResponse, sacp::Error> { .. }
/// ```
///
Expand All @@ -40,15 +44,15 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {

let mut routes: Vec<Route> = Vec::new();

// Collect all #[custom_method("...")] annotations and strip them.
// Collect all #[custom_method(RequestType)] annotations and strip them.
for item in &mut impl_block.items {
if let ImplItem::Fn(method) = item {
let mut route_name = None;
let mut request_type = None;
method.attrs.retain(|attr| {
if attr.path().is_ident("custom_method") {
if let Ok(meta_list) = attr.meta.require_list() {
if let Ok(Lit::Str(s)) = meta_list.parse_args::<Lit>() {
route_name = Some(s.value());
if let Ok(ty) = meta_list.parse_args::<Type>() {
request_type = Some(ty);
}
}
false // strip the attribute
Expand All @@ -57,15 +61,15 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
}
});

if let Some(name) = route_name {
if let Some(req_type) = request_type {
let fn_ident = method.sig.ident.clone();

let param_type = extract_param_type(&method.sig);
let return_type = extract_return_type(&method.sig);
let ok_type = extract_result_ok_type(&method.sig);

routes.push(Route {
method_name: name,
request_type: req_type,
fn_ident,
param_type,
return_type,
Expand All @@ -75,31 +79,31 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
}
}

// Generate the dispatch arms.
// Generate the dispatch arms using matches_method for routing.
let arms: Vec<_> = routes
.iter()
.map(|route| {
let method = &route.method_name;
let req_type = &route.request_type;
let fn_ident = &route.fn_ident;

match &route.param_type {
Some(_) => {
quote! {
#method => {
if <#req_type as sacp::JsonRpcMessage>::matches_method(method) {
let req = serde_json::from_value(params)
.map_err(|e| sacp::Error::invalid_params().data(e.to_string()))?;
let result = self.#fn_ident(req).await?;
serde_json::to_value(&result)
.map_err(|e| sacp::Error::internal_error().data(e.to_string()))
return serde_json::to_value(&result)
.map_err(|e| sacp::Error::internal_error().data(e.to_string()));
}
}
}
None => {
quote! {
#method => {
if <#req_type as sacp::JsonRpcMessage>::matches_method(method) {
let result = self.#fn_ident().await?;
serde_json::to_value(&result)
.map_err(|e| sacp::Error::internal_error().data(e.to_string()))
return serde_json::to_value(&result)
.map_err(|e| sacp::Error::internal_error().data(e.to_string()));
}
}
}
Expand All @@ -111,7 +115,7 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
let schema_entries: Vec<_> = routes
.iter()
.map(|route| {
let method = &route.method_name;
let req_type = &route.request_type;

let params_expr = if let Some(pt) = &route.param_type {
if is_json_value(pt) {
Expand All @@ -120,7 +124,12 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
quote! { Some(generator.subschema_for::<#pt>()) }
}
} else {
quote! { None }
// Even with no handler param, generate schema from the request type
if is_json_value(req_type) {
quote! { None }
} else {
quote! { Some(generator.subschema_for::<#req_type>()) }
}
};

let response_expr = if let Some(ok_ty) = &route.ok_type {
Expand All @@ -141,7 +150,8 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
quote! { Some(#name.to_string()) }
}
} else {
quote! { None }
let name = type_name(req_type);
quote! { Some(#name.to_string()) }
};

let response_name_expr = if let Some(ok_ty) = &route.ok_type {
Expand All @@ -156,12 +166,15 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
};

quote! {
crate::custom_requests::CustomMethodSchema {
method: #method.to_string(),
params_schema: #params_expr,
params_type_name: #params_name_expr,
response_schema: #response_expr,
response_type_name: #response_name_expr,
{
let dummy = <#req_type as Default>::default();
crate::custom_requests::CustomMethodSchema {
method: sacp::JsonRpcMessage::method(&dummy).to_string(),
params_schema: #params_expr,
params_type_name: #params_name_expr,
response_schema: #response_expr,
response_type_name: #response_name_expr,
}
}
}
})
Expand All @@ -174,10 +187,8 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
method: &str,
params: serde_json::Value,
) -> Result<serde_json::Value, sacp::Error> {
match method {
#(#arms)*
_ => Err(sacp::Error::method_not_found()),
}
#(#arms)*
Err(sacp::Error::method_not_found())
}
};

Expand All @@ -202,7 +213,7 @@ pub fn custom_methods(_attr: TokenStream, item: TokenStream) -> TokenStream {
}

struct Route {
method_name: String,
request_type: Type,
fn_ident: syn::Ident,
param_type: Option<Type>,
#[allow(dead_code)]
Expand Down
2 changes: 1 addition & 1 deletion crates/goose-acp/acp-meta.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@
},
{
"method": "_goose/config/extensions",
"requestType": null,
"requestType": "GetExtensionsRequest",
"responseType": "GetExtensionsResponse"
}
]
Expand Down
43 changes: 28 additions & 15 deletions crates/goose-acp/acp-schema.json
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Original file line number Diff line number Diff line change
Expand Up @@ -9,12 +9,12 @@
"type": "string"
},
"config": {
"description": "Extension configuration (see ExtensionConfig variants: Stdio, StreamableHttp, Builtin, Platform)."
"description": "Extension configuration (see ExtensionConfig variants: Stdio, StreamableHttp, Builtin, Platform).",
"default": null
}
},
"required": [
"sessionId",
"config"
"sessionId"
],
"description": "Add an extension to an active session.",
"x-side": "agent",
Expand Down Expand Up @@ -69,6 +69,7 @@
"required": [
"tools"
],
"description": "Tools response.",
"x-side": "agent",
"x-method": "_goose/tools"
},
Expand Down Expand Up @@ -98,12 +99,11 @@
"type": "object",
"properties": {
"result": {
"description": "The resource result from the extension (MCP ReadResourceResult)."
"description": "The resource result from the extension (MCP ReadResourceResult).",
"default": null
}
},
"required": [
"result"
],
"description": "Resource read response.",
"x-side": "agent",
"x-method": "_goose/resource/read"
},
Expand Down Expand Up @@ -147,12 +147,10 @@
"type": "object",
"properties": {
"session": {
"description": "The session object with id, name, working_dir, timestamps, tokens, etc."
"description": "The session object with id, name, working_dir, timestamps, tokens, etc.",
"default": null
}
},
"required": [
"session"
],
"description": "Get a session response.",
"x-side": "agent",
"x-method": "session/get"
Expand Down Expand Up @@ -195,6 +193,7 @@
"required": [
"data"
],
"description": "Export session response.",
"x-side": "agent",
"x-method": "_goose/session/export"
},
Expand All @@ -216,15 +215,20 @@
"type": "object",
"properties": {
"session": {
"description": "The imported session object."
"description": "The imported session object.",
"default": null
}
},
"required": [
"session"
],
"description": "Import session response.",
"x-side": "agent",
"x-method": "_goose/session/import"
},
"GetExtensionsRequest": {
"type": "object",
"description": "List configured extensions and any warnings.",
"x-side": "agent",
"x-method": "_goose/config/extensions"
},
"GetExtensionsResponse": {
"type": "object",
"properties": {
Expand Down Expand Up @@ -340,6 +344,15 @@
],
"description": "Params for _goose/session/import",
"title": "ImportSessionRequest"
},
{
"allOf": [
{
"$ref": "#/$defs/GetExtensionsRequest"
}
],
"description": "Params for _goose/config/extensions",
"title": "GetExtensionsRequest"
}
]
},
Expand Down
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