feat: add stdio transport binding

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "a2a-pb",
     "a2a-grpc",
     "a2a-slimrpc",
+    "a2a-stdio",
     "a2acli",
     "examples/helloworld",
 ]
@@ -25,6 +26,7 @@ a2a-server = { package = "a2a-server-lf", path = "a2a-server", version = "0.2.6"
 a2a-pb = { package = "a2a-pb", path = "a2a-pb", version = "0.1.6" }
 a2a-grpc = { package = "a2a-grpc", path = "a2a-grpc", version = "0.1.11" }
 a2a-slimrpc = { package = "a2a-slimrpc", path = "a2a-slimrpc", version = "0.1.8" }
+a2a-stdio = { package = "agntcy-a2a-stdio", path = "a2a-stdio", version = "0.1.0" }
 
 # Serialization
 serde = { version = "1", features = ["derive"] }

a2a-client/src/rest.rs

@@ -267,7 +267,7 @@ fn parse_rest_error(status: reqwest::StatusCode, body: &str) -> A2AError {
         }
 
         if let Value::Object(values) = raw_detail {
-            details.extend(values.into_iter());
+            details.extend(values);
         }
     }
 

a2a-stdio/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+name = "agntcy-a2a-stdio"
+version = "0.1.0"
+description = "A2A v1 STDIO transport binding for client and server"
+readme = "README.md"
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[lib]
+name = "a2a_stdio"
+
+# Test-only helper subprocess used by integration tests in tests/spawned.rs.
+# Not part of the public surface; kept under tests/bin/ to make that explicit.
+[[bin]]
+name = "stdio_test_helper"
+path = "tests/bin/stdio_test_helper.rs"
+
+[dependencies]
+a2a = { workspace = true }
+a2a-client = { workspace = true }
+a2a-server = { workspace = true }
+tokio = { workspace = true }
+tokio-stream = { workspace = true }
+futures = { workspace = true }
+async-trait = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+thiserror = { workspace = true }
+tracing = { workspace = true }
+uuid = { workspace = true }

a2a-stdio/README.md

@@ -0,0 +1,66 @@
+# a2a-stdio
+
+STDIO transport binding for A2A v1 client and server implementations.
+
+This crate is published as `agntcy-a2a-stdio` and imported in Rust as `a2a_stdio`.
+
+## What It Provides
+
+- `StdioTransport` — `Transport` implementation that spawns an agent
+  subprocess and speaks A2A JSON-RPC over its stdin/stdout
+- `StdioTransportFactory` — `TransportFactory` integration for agent cards
+  that advertise the `STDIO` protocol
+- `StdioServer` — server-side dispatcher that wraps an
+  `a2a_server::RequestHandler` and serves requests over a pair of
+  asynchronous reader/writer streams
+
+## Wire Format
+
+Messages on the wire use LSP-style framing followed by a JSON-RPC 2.0 body:
+
+```text
+Content-Length: <N>\r\n
+Content-Type: application/json\r\n
+\r\n
+<N bytes of JSON>
+```
+
+Method names use the slash-separated A2A convention
+(`message/send`, `tasks/get`, `tasks/subscribe`, ...).
+
+## Handshake
+
+Before serving requests, the server emits a `handshake` message advertising
+its supported variants and features. The client replies with a
+`handshakeAck` that either accepts (selecting a variant) or rejects the
+session.
+
+A session identifier may be passed via the `A2A_SESSION_ID` environment
+variable; otherwise the server generates a UUIDv7.
+
+## Agent Card Target Format
+
+`StdioTransportFactory` interprets `supportedInterfaces[].url` as one of:
+
+- `stdio:///path/to/binary` — spawn the binary with no arguments
+- `stdio:///path/to/binary?arg1&arg2` — spawn with the given arguments
+- `/path/to/binary arg1 arg2` — plain command line, split on whitespace
+
+Arguments in the `stdio://` form are split on `&` and the path is split on
+the first `?`, so individual arguments cannot contain `&` or `?`. Use the
+plain command-line form when those characters are required.
+
+## Install
+
+```toml
+[dependencies]
+a2a = { package = "a2a-lf", version = "0.2" }
+a2a-stdio = { package = "agntcy-a2a-stdio", version = "0.1" }
+```
+
+## Workspace
+
+This crate is part of the `a2a-rs` workspace.
+
+- Repository: https://github.com/a2aproject/a2a-rs
+- Workspace README: https://github.com/a2aproject/a2a-rs/blob/main/README.md