feat: opt-in SWE-2 ACP transport with client-owned tools

[Smartnewb]

Problem

SWE-2 can return action announcements instead of usable client tool calls when a large coding-client prompt and tool catalog are sent through a cloud chat adapter. Client-specific fixes then spread into shared prompts, schemas, and defaults.

Proposed contribution

An opt-in DEVIN_SWE2_TRANSPORT=acp Chat Completions transport using the official signed-in Devin CLI. It exposes a small MCP catalog, retrieves full client tool schemas on demand, and returns ordinary tool calls for the client to execute. Native CLI tools remain denied; original instructions, model access policy, client permission rejections, and provider policy errors are preserved.

Medium/High/Max map to native CLI variants. Tool IDs survive OMO/OpenClaw normalization. Updated continuation instructions restart the prompt with the complete transcript before more work; initializing sessions cannot be evicted; the relay has no implicit five-minute header timeout. Other model routes are unchanged.

Prepared as an experimental draft with no npm runtime dependencies, focused protocol/route tests, and a real CLI/client-tool smoke test. The CLI account, in-memory session limits, text-only support, and rollback switch are documented. I will link the draft PR here.

AI-assisted implementation; no personal configuration, credentials, or conversation traces are included.

[dwgx]

Short version: this repo will not take a second SWE-2 transport. DEVIN_SWE2_TRANSPORT=acp as a Chat Completions subsystem with its own MCP catalog is the same class of change as #259 (vendor router) — a new hop, not a bug fix on the existing wire.

What is already on master after #266 (will be in v3.9.34):

• Connect catalog has swe-2-medium / swe-2-high / swe-2-max. DEVIN_CONNECT=1 still wins over CLI.
• swe-2 / swe-2.0 / swe2 / swe-2.0-high map onto those selectors. They do not fall through to swe-1-6-slow.
• gpt-5.6-luna|sol|terra is Devin Local only when DEVIN_CLI_ENABLED=1. That path is opt-in ACP/print, not a new shared prompt/schema.

#263 (the draft PR) you already withdrew. #266 is the catalog/routing slice that landed. They are not the same mechanism as "SWE-2 only announces actions and never emits client tool calls."

To even consider a transport, I need a failure sample

1. The request body that produces "action announcements, no client tool calls" (redact tokens). Include model name, tool catalog size, and whether DEVIN_CONNECT was on.
2. The raw upstream/CLI output for that turn — the bytes, not a paraphrase. If this is only reproducible through a third-party relay, say so; [Bug] subapi → WindsurfAPI → Codex 路径中 GLM-5.2 工具调用停滞 #236 sat on subapi for 60+ rounds with 0 local repro.

Without those two, this stays a proposal. I will not pre-accept an ACP MCP catalog, on-demand schema fetch, or a continuation-instruction rewrite into the shared prompt path. Client-specific patches do not belong in shared defaults — that part of the report is right, and it is also why the fix cannot be "add another transport."