fix(acp): per-session Agent for model isolation and load_session restore #7115

codefromthecrypt · 2026-02-10T09:08:37Z

Summary

Fix session isolation in the ACP server (goose acp). Previously, all sessions shared a single Agent, so session/set_model on one session changed the model for every session, and session/load_session didn't restore the persisted model.

Now each session/new and session/load_session creates its own Agent with its own provider. Model changes are scoped to the session that requested them. load_session restores the model from the database.

The transport layer is clarified: the Acp-Session-Id header is a connection-scoped UUID (renamed from session_id to acp_session_id), distinct from the Goose session IDs created by session/new.

Test fixtures are refactored to separate Connection (transport + initialize) from Session (prompt, set_model), matching the protocol's own separation.

Type of Change

Bug fix
Refactor / Code quality
Tests

AI Assistance

This PR was created or reviewed with AI assistance

Testing

test_model_set — creates two sessions on the same connection, sets a different model on each, prompts both, and verifies each uses its own model (proves session independence)
test_load_model — sets model to o4-mini, prompts, then loads the same session and verifies the model state is restored from the database

Related Issues

Follow-up to #7112 (model selection support). That PR added session/set_model but all sessions shared one agent, so the model change leaked across sessions.

Each session/new and session/load_session now creates its own Agent with its own provider, fixing model changes leaking across sessions. load_session restores the persisted model from the database. Clarifies transport layer naming: Acp-Session-Id is a connection-scoped UUID, distinct from Goose session IDs. Test fixtures split into Connection and Session traits matching the protocol separation. Signed-off-by: Adrian Cole <adrian@tetrate.io>

codefromthecrypt · 2026-02-10T09:10:28Z

crates/goose-acp/tests/common_tests/mod.rs

+    assert_eq!(models, expected);
+}
+
+pub async fn run_model_set<C: Connection>() {


this is the session independence test. if we later refactor goose to be more session independent internally, we can try to pass this test again.

Copilot

Pull request overview

This PR fixes ACP session isolation by ensuring each Goose session created/loaded via ACP gets its own Agent (and thus its own provider/model state), and updates tests/fixtures and transport naming to reflect the distinction between transport connections and Goose sessions.

Changes:

Create a per-session Agent in session/new and session/load_session, and restore the model from persisted session data on load.
Clarify transport semantics by treating Acp-Session-Id as a connection-scoped UUID (separate from Goose session IDs).
Refactor ACP test fixtures around Connection vs Session, and add tests for model isolation and model restore on load.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/goose-acp/src/server.rs	Moves to per-session `Agent` creation; updates new/load session flows and model switching.
crates/goose-acp/src/transport/http.rs	Uses connection-scoped UUID for `Acp-Session-Id` mapping to transport sessions.
crates/goose-acp/src/transport/websocket.rs	Same as HTTP: connection-scoped UUID and improved naming/log fields.
crates/goose-acp/tests/server_test.rs	Updates tests to use `ClientToAgentConnection` and adds model restore/isolation tests.
crates/goose-acp/tests/common_tests/mod.rs	Refactors shared test logic to use `Connection`/`Session` and adds `run_model_set`/`run_load_model`.
crates/goose-acp/tests/fixtures/mod.rs	Splits `TestSessionConfig` into `TestConnectionConfig` and introduces `Connection` trait.
crates/goose-acp/tests/fixtures/server.rs	Implements new `Connection` + `Session` fixtures and adds load_session/new_session helpers.

crates/goose-acp/src/server.rs

achillelrc · 2026-02-10T09:15:29Z

Great feature i was just looking for this! Just checked out looking forward for the upstream merge!!

Signed-off-by: Adrian Cole <adrian@tetrate.io>

michaelneale · 2026-02-10T23:16:34Z

crates/goose-acp/src/transport/http.rs


 pub(crate) struct HttpState {
    server: Arc<AcpServer>,
+    // Keyed by acp_session_id: a connection-scoped UUID serving many Goose sessions.


confused so 1 acp session != goose session?

yeah this is a mechanic of the transport layer which is the same as MCP basically. when you create a connection to the server, you then have json-rpc on top. on-top are the session/new, fork, load all would be different app layer sessions on the same underlying connection. make sense?

michaelneale · 2026-02-10T23:17:44Z

crates/goose-acp/tests/common_tests/mod.rs

-
-    let models = session.models().unwrap();
-    let expected = SessionModelState::new(
-        ModelId::new(TEST_MODEL),


we don't care about these now?

sorry, I re-ordered the tests alphabetically so that the clusters of features are near eachother in the same file. this wasn't dropped.

michaelneale · 2026-02-10T23:18:10Z

crates/goose-acp/tests/server_test.rs

-            .unwrap(),
-        );
-
-        // Initialization shouldn't fail even though we have a crashing provider factory.


not relevant?

ah sorry I should have made a review comment. this test is now pulled up as a common test, since the fixture is refactored to separate init from new session. https://github.com/block/goose/blob/main/crates/goose-acp/tests/common_tests/mod.rs#L62

michaelneale

felt like more than 70loc change! seems ok - a few questions were inline but mostly my unfamiliarity with session mapping from acp

* origin/main: (107 commits) feat: Allow overriding default bat themes using environment variables (#7140) Make the system prompt smaller (#6991) Pre release script (#7145) Spelling (#7137) feat(mcp): upgrade rmcp to 0.15.0 and advertise MCP Apps UI extension capability (#6927) fix: ensure assistant messages with tool_calls include content field (#7076) fix(canonical): handle gcp_vertex_ai model mapping correctly (#6836) Group dependencies in root Cargo.toml (#6948) refactor: updated elevenLabs API module and `remove button` UX (#6781) fix: we were missing content from langfuse traces (#7135) docs: update username in authors.yml (#7132) fix extension selector syncing issues (#7133) fix(acp): per-session Agent for model isolation and load_session restore (#7115) fix(claude-code): defensive coding improvements for model switching (#7131) feat(claude-code): dynamic model listing and mid-session model switching (#7120) Inline worklet source (#7128) [docs] One shot prompting is dead - Blog Post (#7113) fix: correct spelling of Debbie O'Brien's name in authors.yml (#7127) docs: GCP Vertex AI org policy filtering & update OnboardingProviderSetup component (#7125) feat: replace subagent and skills with unified summon extension (#6964) ... # Conflicts: # Cargo.lock # Cargo.toml

* upstream/main: (109 commits) [docs] Skills Marketplace UI Improvements (block#7158) More no-window flags (block#7122) feat: Allow overriding default bat themes using environment variables (block#7140) Make the system prompt smaller (block#6991) Pre release script (block#7145) Spelling (block#7137) feat(mcp): upgrade rmcp to 0.15.0 and advertise MCP Apps UI extension capability (block#6927) fix: ensure assistant messages with tool_calls include content field (block#7076) fix(canonical): handle gcp_vertex_ai model mapping correctly (block#6836) Group dependencies in root Cargo.toml (block#6948) refactor: updated elevenLabs API module and `remove button` UX (block#6781) fix: we were missing content from langfuse traces (block#7135) docs: update username in authors.yml (block#7132) fix extension selector syncing issues (block#7133) fix(acp): per-session Agent for model isolation and load_session restore (block#7115) fix(claude-code): defensive coding improvements for model switching (block#7131) feat(claude-code): dynamic model listing and mid-session model switching (block#7120) Inline worklet source (block#7128) [docs] One shot prompting is dead - Blog Post (block#7113) fix: correct spelling of Debbie O'Brien's name in authors.yml (block#7127) ...

…ore (block#7115) Signed-off-by: Adrian Cole <adrian@tetrate.io>

codefromthecrypt requested review from alexhancock, Copilot and michaelneale February 10, 2026 09:08

Copilot started reviewing on behalf of codefromthecrypt February 10, 2026 09:09 View session

codefromthecrypt commented Feb 10, 2026

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Copilot AI reviewed Feb 10, 2026

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crates/goose-acp/src/server.rs Outdated Show resolved Hide resolved

codefromthecrypt enabled auto-merge February 10, 2026 10:49

fix(acp): drop sessions lock before awaiting in on_set_model

ebeee49

Signed-off-by: Adrian Cole <adrian@tetrate.io>

michaelneale reviewed Feb 10, 2026

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michaelneale approved these changes Feb 10, 2026

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codefromthecrypt added this pull request to the merge queue Feb 10, 2026

Merged via the queue into main with commit 4ad0aa4 Feb 10, 2026
19 checks passed

codefromthecrypt deleted the load-session-acp branch February 10, 2026 23:26

Tyler-Hardin pushed a commit to Tyler-Hardin/goose that referenced this pull request Feb 11, 2026

fix(acp): per-session Agent for model isolation and load_session rest…

8f329bf

…ore (block#7115) Signed-off-by: Adrian Cole <adrian@tetrate.io>

Tyler-Hardin pushed a commit to Tyler-Hardin/goose that referenced this pull request Feb 11, 2026

fix(acp): per-session Agent for model isolation and load_session rest…

835bee1

…ore (block#7115) Signed-off-by: Adrian Cole <adrian@tetrate.io>

Tyler-Hardin pushed a commit to Tyler-Hardin/goose that referenced this pull request Feb 11, 2026

fix(acp): per-session Agent for model isolation and load_session rest…

6f1aaa9

…ore (block#7115) Signed-off-by: Adrian Cole <adrian@tetrate.io>

github-actions bot mentioned this pull request Feb 12, 2026

chore(release): release version 1.24.0 (minor) #7102

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BrewTestBot mentioned this pull request Feb 12, 2026

block-goose-cli 1.24.0 Homebrew/homebrew-core#267289

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codefromthecrypt commented Feb 10, 2026

Summary

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