bug-ops · bug-ops · Jun 6, 2026 · Jun 5, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -21,15 +21,25 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - `refactor(llm)`: `OpenAiProvider::generation_params()` private helper extracted; removes 4
   duplicate `generation_overrides` tuple expansions in `send_request`, `send_stream_request`,
   `debug_request_json`, and `chat_with_tools`. (#4873)
+- `build(acp)`: bump `agent-client-protocol` 0.12.1 → 0.14.0 and `agent-client-protocol-schema` = 0.13.6; remove dead `agent-client-protocol-tokio` dependency
+- `feat(acp)`: `unstable-session-usage` feature now maps to upstream `unstable_end_turn_token_usage` gate (renamed, not stabilized in 0.14.0)
+- `feat(acp)`: `unstable-elicitation` feature now also enables `agent-client-protocol/unstable_elicitation` core passthrough for `elicitation/create` handler wiring
+- `refactor(acp)`: provider ext-method types renamed to singular: `SetProvidersRequest/Response` → `SetProviderRequest/Response`, `DisableProvidersRequest/Response` → `DisableProviderRequest/Response`
+- `refactor(acp)`: logout, session/close, session/delete, session/resume, and additional-directories handlers are now unconditional (feature flags retained as no-op tombstones for workspace forwarding compatibility)
+
+### Removed
+
+- `refactor(acp)`: `session/set_model` dedicated RPC method removed (deleted upstream in 0.14.0); model switching remains fully available via `session/set_config_option` (config_id="model") and the `$/model` slash command
+- `refactor(acp)`: inbound/outbound message-id echo removed (`PromptRequest.message_id` and `PromptResponse.user_message_id` were removed upstream in 0.14.0)
+
+### Fixed
+
 - `refactor(llm)`: `parse_gemini_error` in `zeph-llm` now delegates the base `ApiError` and
   `ContextLengthExceeded` construction to `crate::http::map_error_response`, consistent with all
   other backends (claude, openai, gonka, cocoon). Gemini-specific `RESOURCE_EXHAUSTED → RateLimited`
   handling is preserved. (#4868)
 - refactor(memory): remove `ScoredCandidate` single-field wrapper in `tiered_retrieval.rs` ([#4867](https://github.com/bug-ops/zeph/issues/4867))
 - fix(memory): replace `.entered()` span guard with removal in `tiered_retrieval.rs` async fn ([#4866](https://github.com/bug-ops/zeph/issues/4866))
-
-### Fixed
-
 - `docs(config)`: `CandleConfig` in `zeph-config` now has a `///` doc comment describing its
   purpose (`[llm.candle]` TOML section) and its relationship to `CandleInlineConfig`. (#4869)
 

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -17,9 +17,8 @@ publish = true
 
 [workspace.dependencies]
 age = { version = "0.11.3", default-features = false }
-agent-client-protocol = "0.12.1"
-agent-client-protocol-schema = "0.13.2"
-agent-client-protocol-tokio = "0.11.1"
+agent-client-protocol = "0.14.0"
+agent-client-protocol-schema = "=0.13.6"
 anyhow = "1.0.102"
 arboard = "3.6.1"
 arc-swap = "1.9.1"

diff --git a/crates/zeph-acp/Cargo.toml b/crates/zeph-acp/Cargo.toml
@@ -17,31 +17,32 @@ default = [
     "unstable-session-delete",
     "unstable-session-fork",
     "unstable-session-usage",
-    "unstable-session-model",
     "unstable-logout",
     "unstable-elicitation",
     "unstable-llm-providers",
 ]
 acp-http = ["dep:axum", "dep:blake3", "dep:dashmap", "dep:async-stream", "dep:tower-http", "dep:subtle", "dep:tower"]
-# session/close is now exposed as session/delete in acp 0.12.1
-unstable-session-delete = ["agent-client-protocol/unstable_session_delete"]
+# session/close and session/delete stabilized in acp 0.14.0; no upstream feature gate needed
+unstable-session-delete = []
 unstable-session-fork = ["agent-client-protocol/unstable_session_fork"]
 # session/resume is stable in acp 0.12.1; no feature gate needed
 unstable-session-resume = []
-unstable-session-usage = ["agent-client-protocol/unstable_session_usage"]
-unstable-session-model = ["agent-client-protocol/unstable_session_model"]
-unstable-elicitation = ["dep:agent-client-protocol-schema", "agent-client-protocol-schema/unstable_elicitation"]
+# renamed from unstable_session_usage in acp 0.14.0; Usage struct + PromptResponse.usage remain gated
+unstable-session-usage = ["agent-client-protocol/unstable_end_turn_token_usage"]
+unstable-elicitation = ["dep:agent-client-protocol-schema", "agent-client-protocol-schema/unstable_elicitation", "agent-client-protocol/unstable_elicitation"]
 unstable-llm-providers = ["dep:agent-client-protocol-schema", "agent-client-protocol-schema/unstable_llm_providers"]
-unstable-logout = ["agent-client-protocol/unstable_logout"]
+# logout stabilized in acp 0.13.0; no upstream feature gate needed
+unstable-logout = []
 unstable-auth-methods = ["agent-client-protocol/unstable_auth_methods"]
 unstable-boolean-config = ["agent-client-protocol/unstable_boolean_config"]
-unstable-message-id = ["agent-client-protocol/unstable_message_id"]
-unstable-session-add-dirs = ["agent-client-protocol/unstable_session_additional_directories"]
+# message-id stabilized in acp 0.14.0; no upstream feature gate needed
+unstable-message-id = []
+# session-add-dirs stabilized in acp 0.14.0; no upstream feature gate needed
+unstable-session-add-dirs = []
 
 [dependencies]
 agent-client-protocol = { workspace = true }
 agent-client-protocol-schema = { workspace = true, optional = true }
-agent-client-protocol-tokio = { workspace = true }
 async-stream = { workspace = true, optional = true }
 axum = { workspace = true, features = ["ws"], optional = true }
 base64.workspace = true

diff --git a/crates/zeph-acp/README.md b/crates/zeph-acp/README.md
@@ -363,7 +363,6 @@ The `initialize` response includes an `auth_hint` key in its metadata map. For s
 | `unstable-session-fork` | unstable | Enables the `fork_session` ACP method. See below. |
 | `unstable-session-resume` | unstable | Enables the `resume_session` ACP method. See below. |
 | `unstable-session-usage` | unstable | Enables `UsageUpdate` events — token counts (input, output, cache) sent to the IDE after each turn. See below. |
-| `unstable-session-model` | unstable | Enables `SetSessionModel` — IDE-driven model switching via a native picker without `session/configure`. See below. |
 | `unstable-session-info-update` | unstable | Enables `SessionInfoUpdate` — agent-generated session title emitted to the IDE after the first turn. See below. |
 | `unstable-elicitation` | unstable | Exposes elicitation schema types (`ElicitationRequest`, etc.) for future agent-loop integration. SDK methods not yet available in 0.10.3. |
 | `unstable-logout` | unstable | Enables the `logout` ACP method and advertises `auth.logout` capability. Zeph logout is a no-op (vault-based auth). |
@@ -379,7 +378,6 @@ zeph-acp = { version = "*", features = [
     "unstable-session-fork",
     "unstable-session-resume",
     "unstable-session-usage",
-    "unstable-session-model",
     "unstable-session-info-update",
     "unstable-elicitation",
     "unstable-logout",
@@ -423,16 +421,6 @@ Enables `UsageUpdate` session events. After each agent turn `ZephAcpAgent` emits
 
 The IDE can use this data to display running cost estimates or token budgets without polling a separate endpoint.
 
-### `unstable-session-model`
-
-Enables `SetSessionModel` handling. When the IDE sends a `set_session_model` request (e.g., from a native model-picker dropdown), `ZephAcpAgent`:
-
-1. Resolves the requested `"provider:model"` key via `ProviderFactory`.
-2. Stores the resolved provider in the session-scoped `provider_override`.
-3. Returns a confirmation to the IDE so the picker reflects the active selection.
-
-This avoids the need to wrap model selection in a `session/configure` call and maps directly to the Zed AI model picker interaction.
-
 ### `unstable-session-info-update`
 
 Enables `SessionInfoUpdate` events. After the first completed turn in a new session, `ZephAcpAgent` emits a `SessionUpdate::SessionInfoUpdate` containing a short, LLM-generated title derived from the opening message. The IDE can use this title to label the session in its sidebar or tab bar.

diff --git a/crates/zeph-acp/src/agent/handlers/mod.rs b/crates/zeph-acp/src/agent/handlers/mod.rs
@@ -1,28 +1,19 @@
 // SPDX-FileCopyrightText: 2026 Andrei G <bug-ops>
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-// Handler stubs for ACP 0.11 migration. Implementations land in PR 2 (#3267).
-// See .local/plan/acp-migration-plan.md §4 Steps 3–4 for the full contract.
-
 pub(crate) mod authenticate;
 pub(crate) mod cancel;
-#[cfg(feature = "unstable-session-delete")]
 pub(crate) mod close_session;
-#[cfg(feature = "unstable-session-delete")]
 pub(crate) mod delete_session;
 pub(crate) mod dispatch;
 #[cfg(feature = "unstable-session-fork")]
 pub(crate) mod fork_session;
 pub(crate) mod initialize;
 pub(crate) mod list_sessions;
 pub(crate) mod load_session;
-#[cfg(feature = "unstable-logout")]
 pub(crate) mod logout;
 pub(crate) mod new_session;
 pub(crate) mod prompt;
-#[cfg(feature = "unstable-session-resume")]
 pub(crate) mod resume_session;
 pub(crate) mod set_session_config_option;
 pub(crate) mod set_session_mode;
-#[cfg(feature = "unstable-session-model")]
-pub(crate) mod set_session_model;
diff --git a/crates/zeph-acp/src/agent/handlers/set_session_model.rs b/crates/zeph-acp/src/agent/handlers/set_session_model.rs