feat(acp): Agent Client Protocol integration — Phase 1 MVP

CHANGELOG.md

@@ -7,6 +7,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 ## [Unreleased]
 
 ### Added
+- `zeph-acp` crate — ACP (Agent Client Protocol) server for IDE embedding (Zed, JetBrains, Neovim) (#763-#766)
+- `--acp` CLI flag to launch Zeph as an ACP stdio server (requires `acp` feature)
+- `acp` feature gate in root `Cargo.toml`; included in `full` feature set
+- `ZephAcpAgent` implementing SDK `Agent` trait with session lifecycle (new, prompt, cancel, load)
+- `loopback_event_to_update` mapping `LoopbackEvent` variants to ACP `SessionUpdate` notifications, with empty chunk filtering
+- `serve_stdio()` transport using `AgentSideConnection` over tokio-compat stdio streams
+- Stream monitor gated behind `ZEPH_ACP_LOG_MESSAGES` env var for JSON-RPC traffic debugging
 - Custom mdBook theme with Zeph brand colors (navy+amber palette from TUI)
 - Z-letter favicon SVG for documentation site
 - Sidebar logo via inline data URI

Cargo.toml

@@ -16,7 +16,9 @@ categories = ["command-line-utilities", "science"]
 
 [workspace.dependencies]
 age = { version = "0.11.2", default-features = false }
+agent-client-protocol = "0.9"
 anyhow = "1.0"
+async-trait = "0.1"
 axum = "0.8"
 base64 = "0.22"
 blake3 = "1.8"
@@ -95,6 +97,7 @@ url = "2.5"
 uuid = "1.21"
 wiremock = "0.6.5"
 zeph-a2a = { path = "crates/zeph-a2a", version = "0.11.6" }
+zeph-acp = { path = "crates/zeph-acp", version = "0.11.6" }
 zeph-channels = { path = "crates/zeph-channels", version = "0.11.6" }
 zeph-core = { path = "crates/zeph-core", version = "0.11.6" }
 zeph-gateway = { path = "crates/zeph-gateway", version = "0.11.6" }
@@ -127,8 +130,9 @@ readme = "README.md"
 
 [features]
 default = []
-full = ["a2a", "daemon", "discord", "gateway", "index", "mock", "otel", "pdf", "scheduler", "slack", "stt", "tui"]
+full = ["a2a", "acp", "daemon", "discord", "gateway", "index", "mock", "otel", "pdf", "scheduler", "slack", "stt", "tui"]
 a2a = ["dep:zeph-a2a", "zeph-a2a?/server"]
+acp = ["dep:zeph-acp"]
 candle = ["zeph-llm/candle", "zeph-core/candle"]
 metal = ["zeph-llm/metal", "zeph-core/metal"]
 cuda = ["zeph-llm/cuda", "zeph-core/cuda"]
@@ -158,6 +162,7 @@ opentelemetry_sdk = { workspace = true, optional = true }
 opentelemetry-otlp = { workspace = true, optional = true }
 tracing-opentelemetry = { workspace = true, optional = true }
 zeph-a2a = { workspace = true, optional = true }
+zeph-acp = { workspace = true, optional = true }
 zeph-channels.workspace = true
 zeph-index = { workspace = true, optional = true }
 zeph-mcp.workspace = true

crates/zeph-acp/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "zeph-acp"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+homepage.workspace = true
+documentation = "https://docs.rs/zeph-acp"
+keywords.workspace = true
+categories.workspace = true
+description = "ACP (Agent Client Protocol) server for IDE embedding"
+readme = "README.md"
+
+[dependencies]
+agent-client-protocol.workspace = true
+async-trait.workspace = true
+thiserror.workspace = true
+tokio = { workspace = true, features = ["io-std", "sync", "macros"] }
+tokio-util = { workspace = true, features = ["compat"] }
+tracing.workspace = true
+uuid = { workspace = true, features = ["v4"] }
+zeph-core.workspace = true
+
+[lints]
+workspace = true