Native Gajae Code (gjc) provider — or a generic ACP driver?

[Yeachan-Heo]

What I'm trying to do

Drive Gajae Code (gjc) from T3 Code's mobile/web/desktop clients, the same way I drive Codex and Claude today.

gjc is a terminal coding agent that runs on the Claude/Codex/Gemini subscription you already pay for, with plan-before-mutation workflows and approval gates on shell/destructive edits. Its remote story today is its own Telegram/Discord/SDK surfaces — T3 Code's app is much better, and the reason I can't use it is only that T3 Code has no gjc harness.

How I do it today

I don't, inside T3 Code. I run npx t3@latest for Codex/Claude, and separately drive gjc through its own broker-bound gjc sdk session CLI. Two control planes for one machine.

Where T3 Code gets in the way

ProviderDriverKind is a closed set (codex, claudeAgent, cursor, grok, opencode) and every driver has its own *Provider.ts / *Adapter.ts pair, so an agent that already speaks a standard protocol still needs a bespoke driver. There is no generic-ACP driver a user can point at an arbitrary <binary> acp command.

What the flow would look like if it worked

Install and authenticate gjc, open T3 Code, pick Gajae Code in the provider picker, and steer it from the phone with the same permission-mode mapping as the other providers.

Why this is cheap for T3 Code specifically

gjc is an ACP agent, and T3 Code already has the ACP machinery — apps/server/src/provider/acp/ with AcpSessionRuntime, AcpAdapterSupport, AcpCoreRuntimeEvents, plus per-vendor support shims (GrokAcpSupport.ts is 108 lines, CursorAcpSupport.ts similar). Grok's whole ACP-side support is a spawn-input builder, an auth-method resolver, and model-selection helpers.

Verified locally against gjc v0.13.3 — raw initialize over stdio:

$ printf '%s\n' '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":1,"clientCapabilities":{"fs":{"readTextFile":true,"writeTextFile":true}}}}' \
  | GJC_ACP_PERMISSION_MODE=prompt gjc acp
{"jsonrpc":"2.0","id":1,"result":{"protocolVersion":1,"agentInfo":{"name":"gajae-code","title":"Gajae Code","version":"0.13.3"},
 "authMethods":[{"id":"agent","name":"Use existing local credentials","description":"Authenticate via the provider keys/OAuth state already configured under ~/.gjc."}],
 "agentCapabilities":{"loadSession":true,"promptCapabilities":{"embeddedContext":true,"image":true},"mcpCapabilities":{"http":true},
 "sessionCapabilities":{"list":{},"fork":{},"resume":{},"close":{},"delete":{}}}}}

So the pieces T3 Code needs are all advertised: loadSession for thread resume, session/list + fork/resume/close/delete for the thread sidebar, image + embedded-context prompts for attachments, spec-shaped session/request_permission for permission modes, and session/cancel settling as cancelled. Upstream GJC runs the pinned external acpx@0.13.0 acp-core-v1 conformance corpus against gjc --mode acp in CI, and emits the spec category on the mode / model / thought_level select options, so mode/model/thinking pickers populate with no vendor metadata.

Concrete shape, if you want it:

• apps/server/src/provider/acp/GjcAcpSupport.ts — spawn ["gjc", "acp"] (binary path overridable), map T3's permission modes onto GJC_ACP_PERMISSION_MODE, auth method agent (local credentials).
• packages/contracts — ProviderDriverKind.make("gjc"), GjcSettings with a binaryPath setting like grok's.
• apps/server/src/provider/Layers/GjcProvider.ts / GjcAdapter.ts — the driver pair; how thin it can get depends on how much of GrokAdapter is genuinely reusable versus vendor-shaped, which you know far better than I do.
• apps/mobile/src/components/ProviderIcon.tsx + docs/user/providers-gjc.md.

The ask

I deliberately did not open a 1.5k-line unsolicited PR — CONTRIBUTING says big features will be rejected, and a bespoke driver in an Effect-TS codebase I don't own is exactly that. Two questions:

1. Would you take a gjc driver at all, and if so should it be a vendor driver like Grok's, or is a generic ACP driver (user supplies command + env, one driver for every ACP agent) the shape you'd rather have? The second is strictly more useful to T3 Code and would cover Gemini, Goose, Junie, Kilo and friends in one go.
2. If yes to either, I'm happy to implement it against whatever contract you name, with the ACP conformance evidence above as the baseline.

I'm the Gajae Code maintainer, so I can also change things on the agent side if T3 Code needs a specific capability advertised differently.