Opencode ACP

[chin4ski]

Opencode has recently added support for ACP: https://opencode.ai/docs/acp/
Anyone knows how configure codecompanion to use it?

[olimorris]

Pretty sure you can take the existing ACP adapters and change the command to point to Opencode

[olimorris]

No I don't want the plugin to become an adapter repository.

This is an ACP adapter. You're probably changing 3 lines of code.

[olimorris]

I will be adding this in #2394

[olimorris]

This has now been merged

[lievi]

Hey, thanks for the effort, love the plugin.

I don't know if I'm doing something wrong, but I'm not receiving the hole message when using the opencode adapter. The message is correct inside opencode itself.

debug chat:

message from opencode

Should I open an issue for this?

[olimorris]

Unfortunately this is likely to be an issue on the opencode end. CodeCompanion doesn't do anything clever here, just implement the protocol according to ACP.

Mine appears to be working perfectly:

2025-11-19.07_58_39.-.WezTerm.mp4

I'd advise pairing your config back to the setup in the minimal.lua contained within the repo and see if there's any other plugin interference. Also, are you on the latest opencode release?

[einarpersson]

Hi! I just tried opencode acp but can't get it to work. I have latest version of codecompanion and opencode. Do i need to start a opencode server manually first?

When i open the chat window neovim hangs for quite some time and then i get the following error message

[ERROR] 2025-11-20 09:16:50
[acp::session_prompt] Connection not established. Call connect_and_initialize() first.

E5108: Error executing lua: ...n.nvim/lua/codecompanion/strategies/chat/acp/handler.lua:145: attempt to index a nil value
stack traceback:
        ...n.nvim/lua/codecompanion/strategies/chat/acp/handler.lua:145: in function 'submit'
        ...ompanion.nvim/lua/codecompanion/strategies/chat/init.lua:1084: in function '_submit_acp'
        ...ompanion.nvim/lua/codecompanion/strategies/chat/init.lua:1166: in function 'submit'
        ...anion.nvim/lua/codecompanion/strategies/chat/keymaps.lua:279: in function 'rhs'
        ...y/codecompanion.nvim/lua/codecompanion/utils/keymaps.lua:85: in function <...y/codecompanion.nvim/lua/codecompanion/utils/keymaps.lua:82>

Here's my config

return {
	"olimorris/codecompanion.nvim",
	-- dir = "~/Projects/einarpersson/codecompanion.nvim/",
	dependencies = {
		"nvim-lua/plenary.nvim",
		"j-hui/fidget.nvim",
	},
	init = function()

		vim.keymap.set({ "n", "v" }, "<C-a>", "<cmd>CodeCompanionActions<cr>", { noremap = true, silent = true })
		vim.keymap.set({ "n", "v" }, "<LocalLeader>a", "<cmd>CodeCompanionChat Toggle<cr>", { noremap = true, silent = true })
		vim.keymap.set("v", "ga", "<cmd>CodeCompanionChat Add<cr>", { noremap = true, silent = true })
	end,
	opts = {
		strategies = {
			chat = {
				adapter = "opencode",
			},
			inline = {
				adapter = "anthropic",
			},
		},
		display = {
			diff = {
				provider = "mini_diff",
			},
			chat = {
				show_token_count = true,
				fold_context = true,
			}
		},
		adapters = {
			acp = {
				opencode = "opencode",
			},
			http = {
				anthropic = function()
					return require("codecompanion.adapters").extend("anthropic", {
						env = {
							api_key = "cmd:cat /home/einar/.config/nvim/.claude.key",
						},
						schema = {
							extended_thinking = {
								default = false,
							},
						},
					})
				end,
			}
		},
	}
}

I also tried with the minimal.lua in this repo and added acp adapter opencode. I get same result.

After a while I could at least send a "hi" and checking the debug info I see this

-- Adapter: "OpenCode"
-- With Command: "opencode acp"
-- Mode: "learning (learning)"
-- Buffer Number: 18
-- Following Buffer: "lua/plugins/codecompanion.lua" (12)

local messages = 
{ {
    _meta = {
      cycle = 1,
      id = 873739340,
      index = 1,
      tag = "system_prompt_from_config"
    },
    content = "You are an AI programming assistant named \"CodeCompanion\", working within the Neovim text editor.\n\nYou can answer general programming questions and perform the following tasks:\n* Answer general programming questions.\n* Explain how the code in a Neovim buffer works.\n* Review the selected code from a Neovim buffer.\n* Generate unit tests for the selected code.\n* Propose fixes for problems in the selected code.\n* Scaffold code for a new workspace.\n* Find relevant code to the user's query.\n* Propose fixes for test failures.\n* Answer questions about Neovim.\n\nFollow the user's requirements carefully and to the letter.\nUse the context and attachments the user provides.\nKeep your answers short and impersonal, especially if the user's context is outside your core tasks.\nUse Markdown formatting in your answers.\nDo not use H1 or H2 markdown headers.\nWhen suggesting code changes or new content, use Markdown code blocks.\nTo start a code block, use 4 backticks.\nAfter the backticks, add the programming language name as the language ID.\nTo close a code block, use 4 backticks on a new line.\nIf the code modifies an existing file or should be placed at a specific location, add a line comment with 'filepath:' and the file path.\nIf you want the user to decide where to place the code, do not add the file path comment.\nIn the code block, use a line comment with '...existing code...' to indicate code that is already present in the file.\nCode block example:\n````languageId\n// filepath: /path/to/file\n// ...existing code...\n{ changed code }\n// ...existing code...\n{ changed code }\n// ...existing code...\n````\nEnsure line comments use the correct syntax for the programming language (e.g. \"#\" for Python, \"--\" for Lua).\nFor code blocks use four backticks to start and end.\nAvoid wrapping the whole response in triple backticks.\nDo not include diff formatting unless explicitly asked.\nDo not include line numbers in code blocks.\n\nWhen given a task:\n1. Think step-by-step and, unless the user requests otherwise or the task is very simple, describe your plan in pseudocode.\n2. When outputting code blocks, ensure only relevant code is included, avoiding any repeating or unrelated code.\n3. End your response with a short suggestion for the next user turn that directly supports continuing the conversation.\n\nAdditional context:\nAll non-code text responses must be written in the English language.\nThe current date is 2025-11-20.\nThe user's Neovim version is 0.11.2.\nThe user is working on a Linux machine. Please respond with system specific commands if applicable.\n",
    opts = {
      visible = false
    },
    role = "system"
  }, {
    _meta = {
      cycle = 1,
      id = 1131121490,
      index = 2,
      sent = true
    },
    content = "hi",
    opts = {
      visible = true
    },
    role = "user"
  } }

and

-- Adapter: "OpenCode"
-- With Command: "opencode acp"
-- Buffer Number: 2
-- Following Buffer: "" (1)

local messages = 
{ {
    _meta = {
      cycle = 1,
      id = 873739340,
      index = 1,
      tag = "system_prompt_from_config"
    },
    content = "You are an AI programming assistant named \"CodeCompanion\", working within the Neovim text editor.\n\nYou can answer general programming questions and perform the following tasks:\n* Answer general programming questions.\n* Explain how the code in a Neovim buffer works.\n* Review the selected code from a Neovim buffer.\n* Generate unit tests for the selected code.\n* Propose fixes for problems in the selected code.\n* Scaffold code for a new workspace.\n* Find relevant code to the user's query.\n* Propose fixes for test failures.\n* Answer questions about Neovim.\n\nFollow the user's requirements carefully and to the letter.\nUse the context and attachments the user provides.\nKeep your answers short and impersonal, especially if the user's context is outside your core tasks.\nUse Markdown formatting in your answers.\nDo not use H1 or H2 markdown headers.\nWhen suggesting code changes or new content, use Markdown code blocks.\nTo start a code block, use 4 backticks.\nAfter the backticks, add the programming language name as the language ID.\nTo close a code block, use 4 backticks on a new line.\nIf the code modifies an existing file or should be placed at a specific location, add a line comment with 'filepath:' and the file path.\nIf you want the user to decide where to place the code, do not add the file path comment.\nIn the code block, use a line comment with '...existing code...' to indicate code that is already present in the file.\nCode block example:\n````languageId\n// filepath: /path/to/file\n// ...existing code...\n{ changed code }\n// ...existing code...\n{ changed code }\n// ...existing code...\n````\nEnsure line comments use the correct syntax for the programming language (e.g. \"#\" for Python, \"--\" for Lua).\nFor code blocks use four backticks to start and end.\nAvoid wrapping the whole response in triple backticks.\nDo not include diff formatting unless explicitly asked.\nDo not include line numbers in code blocks.\n\nWhen given a task:\n1. Think step-by-step and, unless the user requests otherwise or the task is very simple, describe your plan in pseudocode.\n2. When outputting code blocks, ensure only relevant code is included, avoiding any repeating or unrelated code.\n3. End your response with a short suggestion for the next user turn that directly supports continuing the conversation.\n\nAdditional context:\nAll non-code text responses must be written in the English language.\nThe current date is 2025-11-20.\nThe user's Neovim version is 0.11.2.\nThe user is working on a Linux machine. Please respond with system specific commands if applicable.\n",
    opts = {
      visible = false
    },
    role = "system"
  }, {
    _meta = {
      cycle = 1,
      id = 799117247,
      index = 2
    },
    content = "hello",
    opts = {
      visible = true
    },
    role = "user"
  } }

I have read the docs but they seems to suggest that things should "just work".

[georgeharker]

Lmk if you want info on how I piped stuff to opencode acp to figure this out

[olimorris]

Superb detective work 🕵🏼‍♂️💪🏼.

That's super frustrating from opencode as that is not part of the ACP specification.

I wonder if, as a hack, we could use the setup handler on the opencode adapter to prompt the user for a model. Could pass in the ACP handler itself allowing us to call the send_rpc_request function from within the adapter.

What do you think?

Btw would love it if you could update the docs for how users need to update their config.json file. Alas, I don't use opencode.

[georgeharker]

I'll definitely send a PR to update the docs.

The issue is for sure that it sends a nonstandard response.

/tmp/acp_init.json

{
    "jsonrpc": "2.0",
    "id": 0,
    "method": "initialize",
    "params": {
        "protocolVersion": 1,
        "clientCapabilities": {
            "fs": {
                "readTextFile": true,
                "writeTextFile": true
            }
        },
        "clientInfo": {
            "name": "CodeCompanion.nvim",
            "version": "1.0.0"
        }
    }
}

{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "session/new",
    "params": {
        "cwd": "/Users/geohar/Development/clickup-todoist-sync/",
        "mcpServers": [],
        "sessionId": "MYSESSION"
    }
}

cat /tmp/acp_init2.json| jq -rc|opencode acp

responds with

{
    "jsonrpc": "2.0",
    "id": 0,
    "result": {
        "protocolVersion": 1,
        "agentCapabilities": {
            "loadSession": true,
            "mcpCapabilities": {
                "http": true,
                "sse": true
            },
            "promptCapabilities": {
                "embeddedContext": true,
                "image": true
            }
        },
        "authMethods": [
            {
                "description": "Run `opencode auth login` in the terminal",
                "name": "Login with opencode",
                "id": "opencode-login"
            }
        ],
        "agentInfo": {
            "name": "OpenCode",
            "version": "1.0.153"
        }
    }
}
{
    "jsonrpc": "2.0",
    "id": 1,
    "result": {
        "sessionId": "ses_4dc555700ffeUv1T87hbi45RWu",
        "models": {
            "currentModelId": "github-copilot/claude-sonnet-4.5",
            "availableModels": [
                {
                    "modelId": "anthropic/claude-sonnet-4-5-20250929",
                    "name": "Anthropic/Claude Sonnet 4.5"
                },
                {
                    "modelId": "anthropic/claude-sonnet-4-5",
                    "name": "Anthropic/Claude Sonnet 4.5 (latest)"
                },
                {
                    "modelId": "anthropic/claude-sonnet-4-20250514",
                    "name": "Anthropic/Claude Sonnet 4"
                },
                {
                    "modelId": "anthropic/claude-sonnet-4-0",
                    "name": "Anthropic/Claude Sonnet 4 (latest)"
                },
                {
                    "modelId": "anthropic/claude-3-7-sonnet-latest",
                    "name": "Anthropic/Claude Sonnet 3.7 (latest)"
                },
                {
                    "modelId": "anthropic/claude-3-5-haiku-latest",
                    "name": "Anthropic/Claude Haiku 3.5 (latest)"
                },
                {
                    "modelId": "anthropic/claude-opus-4-5-20251101",
                    "name": "Anthropic/Claude Opus 4.5"
                },
                {
                    "modelId": "anthropic/claude-opus-4-5",
                    "name": "Anthropic/Claude Opus 4.5 (latest)"
                },
                {
                    "modelId": "anthropic/claude-opus-4-20250514",
                    "name": "Anthropic/Claude Opus 4"
                },
                {
                    "modelId": "anthropic/claude-opus-4-1-20250805",
                    "name": "Anthropic/Claude Opus 4.1"
                },
                {
                    "modelId": "anthropic/claude-opus-4-1",
                    "name": "Anthropic/Claude Opus 4.1 (latest)"
                },
                {
                    "modelId": "anthropic/claude-opus-4-0",
                    "name": "Anthropic/Claude Opus 4 (latest)"
                },
                {
                    "modelId": "anthropic/claude-haiku-4-5-20251001",
                    "name": "Anthropic/Claude Haiku 4.5"
                },
                {
                    "modelId": "anthropic/claude-haiku-4-5",
                    "name": "Anthropic/Claude Haiku 4.5 (latest)"
                },
                {
                    "modelId": "anthropic/claude-3-sonnet-20240229",
                    "name": "Anthropic/Claude Sonnet 3"
                },
                {
                    "modelId": "anthropic/claude-3-opus-20240229",
                    "name": "Anthropic/Claude Opus 3"
                },
                {
                    "modelId": "anthropic/claude-3-haiku-20240307",
                    "name": "Anthropic/Claude Haiku 3"
                },
                {
                    "modelId": "anthropic/claude-3-7-sonnet-20250219",
                    "name": "Anthropic/Claude Sonnet 3.7"
                },
                {
                    "modelId": "anthropic/claude-3-5-sonnet-20241022",
                    "name": "Anthropic/Claude Sonnet 3.5 v2"
                },
                {
                    "modelId": "anthropic/claude-3-5-sonnet-20240620",
                    "name": "Anthropic/Claude Sonnet 3.5"
                },
                {
                    "modelId": "anthropic/claude-3-5-haiku-20241022",
                    "name": "Anthropic/Claude Haiku 3.5"
                },
                {
                    "modelId": "github-copilot/gemini-3-pro-preview",
                    "name": "GitHub Copilot/Gemini 3 Pro Preview"
                },
                {
                    "modelId": "github-copilot/claude-sonnet-4.5",
                    "name": "GitHub Copilot/Claude Sonnet 4.5"
                },
                {
                    "modelId": "github-copilot/claude-sonnet-4",
                    "name": "GitHub Copilot/Claude Sonnet 4"
                },
                {
                    "modelId": "github-copilot/gpt-5.2",
                    "name": "GitHub Copilot/GPT-5.2"
                },
                {
                    "modelId": "github-copilot/gpt-5.1-codex-mini",
                    "name": "GitHub Copilot/GPT-5.1-Codex-mini"
                },
                {
                    "modelId": "github-copilot/gpt-5.1-codex-max",
                    "name": "GitHub Copilot/GPT-5.1-Codex-max"
                },
                {
                    "modelId": "github-copilot/gpt-5.1-codex",
                    "name": "GitHub Copilot/GPT-5.1-Codex"
                },
                {
                    "modelId": "github-copilot/gpt-5.1",
                    "name": "GitHub Copilot/GPT-5.1"
                },
                {
                    "modelId": "github-copilot/gpt-5-mini",
                    "name": "GitHub Copilot/GPT-5-mini"
                },
                {
                    "modelId": "github-copilot/gpt-5-codex",
                    "name": "GitHub Copilot/GPT-5-Codex"
                },
                {
                    "modelId": "github-copilot/gpt-5",
                    "name": "GitHub Copilot/GPT-5"
                },
                {
                    "modelId": "github-copilot/oswe-vscode-prime",
                    "name": "GitHub Copilot/Raptor Mini (Preview)"
                },
                {
                    "modelId": "github-copilot/o4-mini",
                    "name": "GitHub Copilot/o4-mini (Preview)"
                },
                {
                    "modelId": "github-copilot/o3-mini",
                    "name": "GitHub Copilot/o3-mini"
                },
                {
                    "modelId": "github-copilot/o3",
                    "name": "GitHub Copilot/o3 (Preview)"
                },
                {
                    "modelId": "github-copilot/grok-code-fast-1",
                    "name": "GitHub Copilot/Grok Code Fast 1"
                },
                {
                    "modelId": "github-copilot/gpt-4o",
                    "name": "GitHub Copilot/GPT-4o"
                },
                {
                    "modelId": "github-copilot/gpt-4.1",
                    "name": "GitHub Copilot/GPT-4.1"
                },
                {
                    "modelId": "github-copilot/gemini-2.5-pro",
                    "name": "GitHub Copilot/Gemini 2.5 Pro"
                },
                {
                    "modelId": "github-copilot/gemini-2.0-flash-001",
                    "name": "GitHub Copilot/Gemini 2.0 Flash"
                },
                {
                    "modelId": "github-copilot/claude-opus-41",
                    "name": "GitHub Copilot/Claude Opus 4.1"
                },
                {
                    "modelId": "github-copilot/claude-opus-4.5",
                    "name": "GitHub Copilot/Claude Opus 4.5"
                },
                {
                    "modelId": "github-copilot/claude-opus-4",
                    "name": "GitHub Copilot/Claude Opus 4"
                },
                {
                    "modelId": "github-copilot/claude-haiku-4.5",
                    "name": "GitHub Copilot/Claude Haiku 4.5"
                },
                {
                    "modelId": "github-copilot/claude-3.7-sonnet-thought",
                    "name": "GitHub Copilot/Claude Sonnet 3.7 Thinking"
                },
                {
                    "modelId": "github-copilot/claude-3.7-sonnet",
                    "name": "GitHub Copilot/Claude Sonnet 3.7"
                },
                {
                    "modelId": "github-copilot/claude-3.5-sonnet",
                    "name": "GitHub Copilot/Claude Sonnet 3.5"
                },
                {
                    "modelId": "opencode/big-pickle",
                    "name": "OpenCode Zen/Big Pickle"
                },
                {
                    "modelId": "opencode/gpt-5-nano",
                    "name": "OpenCode Zen/GPT-5 Nano"
                },
                {
                    "modelId": "opencode/grok-code",
                    "name": "OpenCode Zen/Grok Code Fast 1"
                },
                {
                    "modelId": "perplexity/sonar-reasoning-pro",
                    "name": "Perplexity/Sonar Reasoning Pro"
                },
                {
                    "modelId": "perplexity/sonar-reasoning",
                    "name": "Perplexity/Sonar Reasoning"
                },
                {
                    "modelId": "perplexity/sonar-pro",
                    "name": "Perplexity/Sonar Pro"
                },
                {
                    "modelId": "perplexity/sonar",
                    "name": "Perplexity/Sonar"
                }
            ]
        },
        "modes": {
            "availableModes": [
                {
                    "id": "build",
                    "name": "build"
                },
                {
                    "id": "plan",
                    "name": "plan"
                }
            ],
            "currentModeId": "build"
        },
        "_meta": {}
    }
}
{
    "jsonrpc": "2.0",
    "method": "session/update",
    "params": {
        "sessionId": "ses_4dc555700ffeUv1T87hbi45RWu",
        "update": {
            "sessionUpdate": "available_commands_update",
            "availableCommands": [
                {
                    "name": "init",
                    "description": "create/update AGENTS.md"
                },
                {
                    "name": "review",
                    "description": "review changes [commit|branch|pr], defaults to uncommitted"
                },
                {
                    "name": "compact",
                    "description": "compact the session"
                }
            ]
        }
    }
}

Options include using setup to do a pre-query as you suggested then prompting the user

Alternatively,

you can define alternates like so:

    require("codecompanion").setup({
        adapters = {
            acp = {
                opencode = function()
                    return require("codecompanion.adapters").extend("opencode", {
                        commands = {
                            default = {   -- this will use your opencode/config.json setting
                                "opencode",
                                "acp",
                            },
                            copilot_sonnet_4_5 = {
                                "opencode",
                                "acp", "-m", "github-copilot/claude-sonnet-4.5"
                            },
                            copilot_opus_4_5 = {
                                "opencode",
                                "acp", "-m", "github-copilot/claude-opus-4.5"
                            },
                            anthropic_sonnet_4_5 = {
                                "opencode",
                                "acp", "-m", "anthropic/claude-sonnet-4.5"
                            },
                            anthropic_opus_4_5 = {
                                "opencode",
                                "acp", "-m", "anthropic/claude-opus-4.5"
                            }
                        },
                    })
                end,
            },
        }
    })

I have a PR incoming which suggests this for the docs.

I see the picker support in various parts of the code, but I'm not totally sure the best way to set that up.

I do know that

opencode models

will give a list that could be used in a picker

[georgeharker]

#2531 for PR

[olimorris]

Thanks for this. I spoke to the Zed about the model state some time ago and they informed me it was liable to change and not part of the spec. It's not cool that OpenCode is basically unusable because of how they've implemented it.

I'll keep an eye out for models being merged and then add it into the ACP spec.

Thanks again.