feat(acp): add config option settings modal

README.md

@@ -725,6 +725,7 @@ These keybindings are automatically set in Agentic buffers:
 | `<localLeader>s` | n     | Switch ACP provider (preserves chat history)                    |
 | `<localLeader>m` | n     | Switch model without (preserves chat history)                   |
 | `<localLeader>t` | n     | Select thought effort level (model-dependent on Claude)         |
+| `<localLeader>o` | n     | Open options modal                                              |
 | `q`              | n     | Close chat widget                                               |
 | `d`              | n     | Remove file, code selection, or diagnostic at cursor            |
 | `d`              | v     | Remove multiple selected files, code selections, or diagnostics |
@@ -758,6 +759,7 @@ your setup:
         switch_provider = "<localLeader>s",  -- Switch ACP provider
         switch_model = "<localLeader>m",     -- Switch model
         change_thought_level = "<localLeader>t",  -- Select thought effort level
+        open_options = "<localLeader>o",  -- Open options modal
       },
 
       -- Keybindings for the prompt buffer only

doc/agentic.txt

@@ -577,6 +577,7 @@ These keybindings are automatically set in Agentic buffers:
   <localLeader>s         n       Switch ACP provider (keeps history)
   <localLeader>m         n       Switch model (keeps history)
   <localLeader>t         n       Select thought effort level (model-dependent)
+  <localLeader>o         n       Open options modal
   q                      n       Close chat widget
   d                      n/v     Remove file/selection/diagnostic
   ]]                     n       Next chat heading
@@ -612,6 +613,7 @@ Override default keybindings via the `keymaps` config option:
         switch_provider = "<localLeader>s",
         switch_model = "<localLeader>m",
         change_thought_level = "<localLeader>t",
+        open_options = "<localLeader>o",
       },
       prompt = {
         submit = {

lua/agentic/acp/acp_client.lua

@@ -73,6 +73,11 @@ function ACPClient:new(config, on_ready)
                 writeTextFile = false,
             },
             terminal = false,
+            session = {
+                configOptions = {
+                    boolean = vim.empty_dict(),
+                },
+            },
         },
         auth_methods = {},
         ready_listeners = {},
@@ -780,22 +785,9 @@ function ACPClient:set_mode(session_id, mode_id, callback)
 end
 
 --- Set a config option value for a session
---- @param session_id string
---- @param config_id string
---- @param config_value string
+--- @param params agentic.acp.SetConfigOptionParams
 --- @param callback fun(result: table|nil, err: agentic.acp.ACPError|nil)
-function ACPClient:set_config_option(
-    session_id,
-    config_id,
-    config_value,
-    callback
-)
-    local params = {
-        sessionId = session_id,
-        configId = config_id,
-        value = config_value,
-    }
-
+function ACPClient:set_config_option(params, callback)
     self:_send_request("session/set_config_option", params, callback)
 end
 

lua/agentic/acp/acp_client.test.lua

@@ -30,6 +30,9 @@ describe("ACPClient", function()
     --- @type fun(message: agentic.acp.ResponseRaw)|nil
     local captured_on_message
 
+    --- @type agentic.acp.InitializeParams|nil
+    local captured_initialize_params
+
     local PROMPT_CAPS =
         { image = false, audio = false, embeddedContext = false }
 
@@ -71,6 +74,7 @@ describe("ACPClient", function()
         transport_send_stub:invokes(function(_self, data)
             local decoded = vim.json.decode(data)
             if decoded.method == "initialize" and captured_on_message then
+                captured_initialize_params = decoded.params
                 captured_on_message({
                     jsonrpc = "2.0",
                     method = "initialize",
@@ -118,6 +122,7 @@ describe("ACPClient", function()
     before_each(function()
         package.loaded["agentic.acp.acp_client"] = nil
         package.loaded["agentic.acp.acp_transport"] = nil
+        captured_initialize_params = nil
 
         local Logger = require("agentic.utils.logger")
         logger_debug_stub = spy.stub(Logger, "debug")
@@ -151,6 +156,28 @@ describe("ACPClient", function()
         create_transport_stub:revert()
     end)
 
+    describe("initialize", function()
+        it("advertises boolean session config options as an object", function()
+            assert.equal("[]", vim.json.encode({}))
+            create_ready_client()
+
+            assert.is_not_nil(captured_initialize_params)
+            --- @cast captured_initialize_params agentic.acp.InitializeParams
+            assert.is_not_nil(
+                captured_initialize_params.clientCapabilities.session
+            )
+
+            local config_options =
+                captured_initialize_params.clientCapabilities.session.configOptions
+            assert.is_not_nil(config_options)
+            --- @cast config_options agentic.acp.SessionConfigOptionsCapabilities
+            assert.is_not_nil(config_options.boolean)
+
+            local encoded = vim.json.encode(captured_initialize_params)
+            assert.is_not_nil(encoded:find('"boolean":{}', 1, true))
+        end)
+    end)
+
     describe("list_sessions", function()
         it("sends session/list request", function()
             local client = create_ready_client(LIST_CAPS)
@@ -278,6 +305,77 @@ describe("ACPClient", function()
         end)
     end)
 
+    describe("set_config_option", function()
+        it("sends select values without a type", function()
+            local client = create_ready_client()
+            --- @diagnostic disable-next-line: invisible
+            local send_request_stub = spy.stub(client, "_send_request")
+
+            client:set_config_option({
+                sessionId = "s1",
+                configId = "model",
+                value = "opus",
+            }, function() end)
+
+            local params = send_request_stub.calls[1][3]
+            assert.equal(
+                "session/set_config_option",
+                send_request_stub.calls[1][2]
+            )
+            assert.same({
+                sessionId = "s1",
+                configId = "model",
+                value = "opus",
+            }, params)
+            assert.is_nil(params.type)
+        end)
+
+        it("sends boolean true with the boolean type", function()
+            local client = create_ready_client()
+            --- @diagnostic disable-next-line: invisible
+            local send_request_stub = spy.stub(client, "_send_request")
+
+            client:set_config_option({
+                sessionId = "s1",
+                configId = "fast",
+                type = "boolean",
+                value = true,
+            }, function() end)
+
+            assert.equal(
+                "session/set_config_option",
+                send_request_stub.calls[1][2]
+            )
+            assert.same({
+                sessionId = "s1",
+                configId = "fast",
+                type = "boolean",
+                value = true,
+            }, send_request_stub.calls[1][3])
+        end)
+
+        it("sends boolean false with the boolean type", function()
+            local client = create_ready_client()
+            --- @diagnostic disable-next-line: invisible
+            local send_request_stub = spy.stub(client, "_send_request")
+
+            client:set_config_option({
+                sessionId = "s1",
+                configId = "fast",
+                type = "boolean",
+                value = false,
+            }, function() end)
+
+            local params = send_request_stub.calls[1][3]
+            assert.equal(
+                "session/set_config_option",
+                send_request_stub.calls[1][2]
+            )
+            assert.is_false(params.value)
+            assert.equal("boolean", params.type)
+        end)
+    end)
+
     describe("_drain_pending_callbacks", function()
         local original_schedule = vim.schedule
 

lua/agentic/acp/acp_client_types.lua

@@ -7,9 +7,16 @@
 --- @field name string
 --- @field version string
 
+--- @class agentic.acp.SessionConfigOptionsCapabilities
+--- @field boolean? table
+
+--- @class agentic.acp.ClientSessionCapabilities
+--- @field configOptions? agentic.acp.SessionConfigOptionsCapabilities
+
 --- @class agentic.acp.ClientCapabilities
 --- @field fs agentic.acp.FileSystemCapability
 --- @field terminal boolean
+--- @field session? agentic.acp.ClientSessionCapabilities
 
 --- @class agentic.acp.InitializeParams
 --- @field protocolVersion number
@@ -173,28 +180,55 @@
 --- @field currentModelId string
 
 --- @class agentic.acp.ConfigOption.Option
---- @field description string
+--- @field description? string
 --- @field name string
 --- @field value string
 
 --- @alias agentic.acp.ConfigOption.Category
 --- | "mode"
 --- | "model"
+--- | "model_config"
 --- | "thought_level"
+--- | "other"
 
 --- @class agentic.acp.ConfigOption
 --- @field id string
---- @field category agentic.acp.ConfigOption.Category
+--- @field category? agentic.acp.ConfigOption.Category
+--- @field type? "select"
 --- @field currentValue string
 --- @field description string
 --- @field name string
---- @field options agentic.acp.ConfigOption.Option[]
+--- @field options? agentic.acp.ConfigOption.Option[]
+
+--- @class agentic.acp.BooleanConfigOption : agentic.acp.ConfigOption
+--- @field type "boolean"
+--- @field currentValue boolean
+--- @field description? string
+
+--- @class agentic.acp.SelectConfigOptionParams
+--- @field sessionId string
+--- @field configId string
+--- @field value string
+
+--- @class agentic.acp.BooleanConfigOptionParams
+--- @field sessionId string
+--- @field configId string
+--- @field type "boolean"
+--- @field value boolean
+
+--- @alias agentic.acp.SetConfigOptionParams
+--- | agentic.acp.SelectConfigOptionParams
+--- | agentic.acp.BooleanConfigOptionParams
+
+--- @alias agentic.acp.AnyConfigOption
+--- | agentic.acp.ConfigOption
+--- | agentic.acp.BooleanConfigOption
 
 --- @class agentic.acp.SessionCreationResponse
 --- @field sessionId string
 --- @field modes? agentic.acp.ModesInfo
 --- @field models? agentic.acp.ModelsInfo
---- @field configOptions? agentic.acp.ConfigOption[]
+--- @field configOptions? agentic.acp.AnyConfigOption[]
 
 --- @alias agentic.acp.ResponseRawParams
 --- | { sessionId: string, update: agentic.acp.SessionUpdateMessage }
@@ -257,7 +291,7 @@
 
 --- @class agentic.acp.ConfigOptionsUpdate
 --- @field sessionUpdate "config_option_update"
---- @field configOptions agentic.acp.ConfigOption[]
+--- @field configOptions agentic.acp.AnyConfigOption[]
 
 --- @alias agentic.acp.SessionUpdateMessage
 --- | agentic.acp.UserMessageChunk