feat(goose-acp): enable parallel sessions with isolated agent state #6363

codefromthecrypt · 2026-01-06T21:27:31Z

Summary

This PR makes it possible to run ACP agents and sessions in parallel, with critical state isolated to each agent instance.

Before, we were using global singletons for most state, which made it impossible to change configuration without ENV or subprocess isolation. Moreover, unlike platform, built-in extensions launched subprocesses which implied you need a binary entrypoint to run them.

This PR extracts the most critical state into structs and ensures consistent threading to call sites. It also reconfigures built-in extensions to run in-process, via duplex streams.

Legacy entrypoints retain global singletons despite ACP entrypoints being isolated. This was done to allow progress, particularly to implement goose-server with ACP. This is also due to the pending PR to replace the CLI. We don't want to do too much work for code that is going to be replaced.

The most important impact is the new goose-acp crate which contains isolated code for critical paths even though the CLI entrypoint that uses it will act the same.

Later in the tests section you will see how the combination of these changes allow more ACP integration tests than before to complete in less than a second.

Type of Change

Feature
Refactor / Code quality
Tests

AI Assistance

This PR was created or reviewed with AI assistance

Testing

Now that built-in are in-process like platform extensions, we don't need to build binaries to run ACP tests.
Since we parameterized the GooseAcpAgent to accept variables via AgentConfig, tests don't rely on ENV variables.

Above and other changes allow us to safely run tests in parallel, removing env-lock, serial and reset patterns.
This means despite having more ACP integration tests, our performance is incredibly faster.

Crate	MAIN	THIS PR	Speedup
goose-acp	42.22s	0.77s	55x

Works cited

What this PR does is a step towards a more modular codebase which avoids global singletons.
Some projects I studied for reference were:

hyperswitch - AppState takes storage config
lemmy - LemmyContext created once, passed to handlers
typst - Engine requires all dependencies at construction

Related Issues

feat: acp client provider #6305

Copilot

Pull request overview

This PR enables parallel ACP agent sessions with isolated state, eliminating global singleton dependencies. The main achievement is enabling safe concurrent test execution, improving test performance by 55x (42.22s → 0.77s for goose-acp tests).

Key Changes:

Introduces goose-acp crate with isolated ACP agent implementation
Refactors PermissionInspector to pass permission_mode per-call instead of storing in shared mutable state
Converts SessionManager and PermissionManager to instance-based with thread-safe internals
Built-in extensions now run in-process via duplex streams instead of subprocess
Consolidates workspace dependencies to enforce consistency

Reviewed changes

Copilot reviewed 79 out of 88 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
`crates/goose/src/agents/agent.rs`	Introduces `AgentConfig` struct to thread session/permission managers through agent
`crates/goose/src/permission/permission_inspector.rs`	Removes shared mode state; `goose_mode` passed per `inspect()` call
`crates/goose/src/session/session_manager.rs`	Refactors from static methods to instance-based with lazy pool initialization
`crates/goose/src/config/permission.rs`	Adds `RwLock` for thread-safe permission map access
`crates/goose/src/agents/mcp_client.rs`	Adds `session_id` parameter to `call_tool` trait method
`crates/goose/src/agents/extension_manager.rs`	Changes built-in extensions to run in-process via duplex streams
`crates/goose-acp/*`	New crate for isolated ACP server implementation
`crates/goose-mcp/src/lib.rs`	Adds `BUILTIN_EXTENSIONS` map for in-process spawning
Test files	Removes serial test constraints, adds per-test temp directories

Signed-off-by: Adrian Cole <[email protected]>

codefromthecrypt

notes on the important things

codefromthecrypt · 2026-01-07T22:14:51Z

crates/goose/tests/mcp_replays/github-mcp-serverstdio

 STDIN: {"jsonrpc":"2.0","method":"notifications/initialized"}
 STDERR: time=2025-12-11T17:58:47.642-05:00 level=INFO msg="session initialized"
-STDIN: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"_meta":{"progressToken":0},"name":"get_file_contents","arguments":{"owner":"block","path":"README.md","repo":"goose","sha":"ab62b863c1666232a67048b6c4e10007a2a5b83c"}}}
+STDIN: {"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"_meta":{"goose-session-id":"test-session-id","progressToken":0},"name":"get_file_contents","arguments":{"owner":"block","path":"README.md","repo":"goose","sha":"ab62b863c1666232a67048b6c4e10007a2a5b83c"}}}


now that session is propagated via parameter in the case we always know it, the expectation file bumped for good reason.

codefromthecrypt · 2026-01-07T22:16:17Z

crates/goose/tests/mcp_integration_test.rs

    }
 }

+fn build_and_get_binary_path() -> PathBuf {


now that builtin extensions no longer require being launched as subprocesses (mcp xxx args), ACP doesn't need a build to run tests. This leaves only one path where we launch processes in tests, the old one for MCP replay, only used when recording. This is put back to exactly the same code from before we needed to extract a common cargo build utility.

codefromthecrypt · 2026-01-07T22:21:06Z

crates/goose/src/scheduler_trait.rs

    ) -> Result<Option<(String, DateTime<Utc>)>, SchedulerError>;
 }
+
+const UNAVAILABLE_MESSAGE: &str = "Scheduler not available. This tool only works in server mode.";


before we had a single call site we noticed scheduler in use and disabled it for CLI sessions. This extracts so it isn't optional. Unless there's a good reason to have CLI sessions fail on scheduler, I recommend in this PR or the next just letting them work and removing this workaround and/or only using it in tests

codefromthecrypt · 2026-01-07T22:22:58Z

crates/goose/src/session/session_manager.rs


-static SESSION_STORAGE: OnceCell<Arc<SessionStorage>> = OnceCell::const_new();
+static SESSION_STORAGE: LazyLock<Arc<SessionStorage>> =
+    LazyLock::new(|| Arc::new(SessionStorage::new(Paths::data_dir())));


in order to propagate and also still have a singleton I looked around at about 10 rust projects and this lazy lock pattern seemed the best, as old sites still get a global singleton until/unless updated, and new can propagate through in all cases the actual connect stuff is deferred to first.

codefromthecrypt · 2026-01-07T22:24:13Z

crates/goose/src/permission/permission_confirmation.rs

    AllowOnce,
    Cancel,
    DenyOnce,
+    AlwaysDeny,


we were missing this even though our permissions system allows persistence of deny. This is needed for ACP and the motivation was testing permissions which had a bug and they now are testable without clobbering or ENV

codefromthecrypt · 2026-01-07T22:33:57Z

crates/goose-acp/tests/server_test.rs

+        .unwrap();
+}
+
+#[test_case(Some(PermissionOptionKind::AllowAlways), ToolCallStatus::Completed, "user:\n  always_allow:\n  - lookup__get_code\n  ask_before: []\n  never_allow: []\n"; "allow_always")]


this is the new test and notice no ACP test requires serial anymore, and none use ENV or clobber eachother's database or permissions files

codefromthecrypt · 2026-01-07T22:38:55Z

crates/goose/src/config/permission.rs


+const PERMISSION_FILE: &str = "permission.yaml";
+
+static PERMISSION_MANAGER: LazyLock<Arc<PermissionManager>> =


permission manager needs to be a singleton where used, so I used exact same pattern as session storage. before depending on call site reads might come from memory which could have problems when not shared. now it is always shared and pushed down consistently

codefromthecrypt · 2026-01-08T00:49:16Z

can't change the head branch without a new PR so re-opened here so it is a branch off this repo instead of my fork #6392

codefromthecrypt force-pushed the feat/scacp-10-library-mode branch 3 times, most recently from c617a9e to c3f5398 Compare January 7, 2026 02:56

codefromthecrypt mentioned this pull request Jan 7, 2026

fix(ci): add missing dependencies to openapi-schema-check job #6367

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2 tasks

codefromthecrypt force-pushed the feat/scacp-10-library-mode branch 2 times, most recently from e65da8c to 160d5ad Compare January 7, 2026 09:27

codefromthecrypt marked this pull request as ready for review January 7, 2026 09:52

Copilot AI review requested due to automatic review settings January 7, 2026 09:52

Copilot started reviewing on behalf of codefromthecrypt January 7, 2026 09:52 View session

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codefromthecrypt added 2 commits January 8, 2026 06:36

fix(ci): add missing dependencies to openapi-schema-check job

634bc74

Signed-off-by: Adrian Cole <[email protected]>

feat(goose-acp): enable parallel sessions with isolated agent state

0fc93f2

Signed-off-by: Adrian Cole <[email protected]>

codefromthecrypt force-pushed the feat/scacp-10-library-mode branch from 160d5ad to 0fc93f2 Compare January 7, 2026 22:37

codefromthecrypt commented Jan 7, 2026

View reviewed changes

michaelneale requested review from DOsinga and zanesq January 7, 2026 23:58

michaelneale assigned michaelneale and DOsinga Jan 7, 2026

codefromthecrypt closed this Jan 8, 2026

codefromthecrypt deleted the feat/scacp-10-library-mode branch January 8, 2026 00:50

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		const PERMISSION_FILE: &str = "permission.yaml";

		static PERMISSION_MANAGER: LazyLock<Arc<PermissionManager>> =

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