fix(agent): prevent hidden agents from switching the active mode

lua/opencode/commands/handlers/workflow.lua

@@ -11,6 +11,7 @@ local input_window = require('opencode.ui.input_window')
 local ui = require('opencode.ui.ui')
 local nvim = vim['api']
 local session_runtime = require('opencode.services.session_runtime')
+local agent_model = require('opencode.services.agent_model')
 
 local M = {
   actions = {},
@@ -243,6 +244,13 @@ M.actions.run_user_command = Promise.async(function(name, args)
     local model = command_cfg.model or state.current_model
     local agent = command_cfg.agent or state.current_mode
 
+    if command_cfg.agent then
+      local available_agents = config_file.get_opencode_agents():await()
+      if vim.tbl_contains(available_agents, agent) then
+        agent_model.switch_to_mode(agent)
+      end
+    end
+
     local active_session = get_active_session_or_warn('No active session')
     if not active_session then
       return

lua/opencode/services/agent_model.lua

@@ -174,7 +174,10 @@ M.initialize_current_model = Promise.async(function(opts)
           state.model.set_model(model_str)
         end
         if msg.info.mode and state.current_mode ~= msg.info.mode then
-          state.model.set_mode(msg.info.mode)
+          local available_agents = config_file.get_opencode_agents():await()
+          if vim.tbl_contains(available_agents, msg.info.mode) then
+            state.model.set_mode(msg.info.mode)
+          end
         end
         return state.current_model
       end

lua/opencode/services/messaging.lua

@@ -2,6 +2,7 @@ local state = require('opencode.state')
 local context = require('opencode.context')
 local util = require('opencode.util')
 local config = require('opencode.config')
+local config_file = require('opencode.config_file')
 local Promise = require('opencode.promise')
 local log = require('opencode.log')
 local agent_model = require('opencode.services.agent_model')
@@ -48,7 +49,10 @@ M.send_message = Promise.async(function(prompt, opts)
 
   if opts.agent then
     params.agent = opts.agent
-    state.model.set_mode(opts.agent)
+    local available_agents = config_file.get_opencode_agents():await()
+    if vim.tbl_contains(available_agents, opts.agent) then
+      state.model.set_mode(opts.agent)
+    end
   end
 
   params.parts = context.format_message(prompt, opts.context):await()

tests/unit/api_spec.lua

@@ -463,6 +463,8 @@ describe('opencode.api', function()
         stub(api, 'open_input').invokes(function()
           return resolved('done')
         end)
+        local config_file = require('opencode.config_file')
+        stub(config_file, 'get_opencode_agents').returns(resolved({ 'plan', 'build' }))
       end)
 
       it('invokes run with correct model and agent', function()

tests/unit/services_agent_model_spec.lua

@@ -144,6 +144,9 @@ describe('opencode.services.agent_model', function()
   it('restores the latest session model and mode when explicitly requested', function()
     state.model.set_model('openai/gpt-4.1')
     state.model.set_mode('plan')
+
+    stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
     state.renderer.set_messages({
       {
         info = {
@@ -160,5 +163,33 @@ describe('opencode.services.agent_model', function()
     assert.equal('anthropic/claude-3-opus', model)
     assert.equal('anthropic/claude-3-opus', state.current_model)
     assert.equal('build', state.current_mode)
+
+    config_file.get_opencode_agents:revert()
+  end)
+
+  it('does not restore mode to a hidden agent from messages', function()
+    state.model.set_model('openai/gpt-4.1')
+    state.model.set_mode('build')
+
+    stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
+    state.renderer.set_messages({
+      {
+        info = {
+          id = 'm1',
+          providerID = 'anthropic',
+          modelID = 'claude-3-opus',
+          mode = 'hidden-xyz',
+        },
+      },
+    })
+
+    local model = agent_model.initialize_current_model({ restore_from_messages = true }):wait()
+
+    assert.equal('anthropic/claude-3-opus', model)
+    assert.equal('anthropic/claude-3-opus', state.current_model)
+    assert.equal('build', state.current_mode)
+
+    config_file.get_opencode_agents:revert()
   end)
 end)

tests/unit/services_messaging_spec.lua

@@ -7,6 +7,7 @@ loaded.services_messaging_spec = true
 
 local messaging = require('opencode.services.messaging')
 local session_runtime = require('opencode.services.session_runtime')
+local config_file = require('opencode.config_file')
 local state = require('opencode.state')
 local Promise = require('opencode.promise')
 local stub = require('luassert.stub')
@@ -52,6 +53,8 @@ describe('opencode.services.messaging', function()
     state.ui.set_windows({ mock = 'windows' })
     state.session.set_active({ id = 'sess1' })
 
+    stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
     local create_called = false
     state.api_client.create_message = function(_, sid, params)
       create_called = true
@@ -69,6 +72,59 @@ describe('opencode.services.messaging', function()
     assert.equal(state.current_model, 'test/model')
     assert.is_true(create_called)
     state.api_client.create_message = orig
+    config_file.get_opencode_agents:revert()
+  end)
+
+  it('does not switch mode when agent is hidden', function()
+    state.ui.set_windows({ mock = 'windows' })
+    state.session.set_active({ id = 'sess1' })
+    state.model.set_mode('build')
+
+    stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
+    local captured_params = nil
+    local orig = state.api_client.create_message
+    state.api_client.create_message = function(_, sid, params)
+      captured_params = params
+      return Promise.new():resolve({ id = 'm1' })
+    end
+
+    messaging.send_message('hello world', { agent = 'hidden-xyz' })
+    vim.wait(50, function()
+      return captured_params ~= nil
+    end)
+
+    assert.equal('build', state.current_mode)
+    assert.equal('hidden-xyz', captured_params.agent)
+
+    state.api_client.create_message = orig
+    config_file.get_opencode_agents:revert()
+  end)
+
+  it('switches mode when agent is visible', function()
+    state.ui.set_windows({ mock = 'windows' })
+    state.session.set_active({ id = 'sess1' })
+    state.model.set_mode('build')
+
+    stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
+    local captured_params = nil
+    local orig = state.api_client.create_message
+    state.api_client.create_message = function(_, sid, params)
+      captured_params = params
+      return Promise.new():resolve({ id = 'm1' })
+    end
+
+    messaging.send_message('hello world', { agent = 'plan' })
+    vim.wait(50, function()
+      return captured_params ~= nil
+    end)
+
+    assert.equal('plan', state.current_mode)
+    assert.equal('plan', captured_params.agent)
+
+    state.api_client.create_message = orig
+    config_file.get_opencode_agents:revert()
   end)
 
   it('increments and decrements user_message_count correctly', function()

tests/unit/services_session_runtime_spec.lua

@@ -650,6 +650,9 @@ describe('opencode.services.session_runtime', function()
     it('restores the latest session model and mode when explicitly requested', function()
       state.model.set_model('openai/gpt-4.1')
       state.model.set_mode('plan')
+
+      stub(config_file, 'get_opencode_agents').returns(Promise.new():resolve({ 'plan', 'build' }))
+
       state.renderer.set_messages({
         {
           info = {
@@ -666,6 +669,8 @@ describe('opencode.services.session_runtime', function()
       assert.equal('anthropic/claude-3-opus', model)
       assert.equal('anthropic/claude-3-opus', state.current_model)
       assert.equal('build', state.current_mode)
+
+      config_file.get_opencode_agents:revert()
     end)
   end)
 end)