fix: preserve agent field during command expansion

e2e/exec_command_agent_test.go

@@ -0,0 +1,18 @@
+package e2e_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestExec_CommandTargetsAgent verifies that invoking a /command which targets
+// a sub-agent sends the instructions directly to that agent, bypassing the root
+// agent (no transfer_task round-trip). The recorded cassette only contains a
+// single request carrying the specialist agent's system prompt, which proves
+// the message reached the specialist directly.
+func TestExec_CommandTargetsAgent(t *testing.T) {
+	out := runCLI(t, "run", "--exec", "testdata/command_agent.yaml", "/ask What's 2+2?")
+
+	require.Equal(t, "SPECIALIST: 4", out)
+}

e2e/testdata/cassettes/TestExec_CommandTargetsAgent.yaml

@@ -0,0 +1,39 @@
+---
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.openai.com
+        body: '{"messages":[{"content":"You are the SPECIALIST agent. Answer the user''s question directly and\nconcisely. Always prefix your answer with the single word: SPECIALIST.\n","role":"system"},{"content":"What''s 2+2?","role":"user"}],"model":"gpt-3.5-turbo","stream_options":{"include_usage":true},"stream":true}'
+        url: https://api.openai.com/v1/chat/completions
+        method: POST
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        body: |+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{"role":"assistant","content":"","refusal":null},"logprobs":null,"finish_reason":null}],"usage":null,"obfuscation":"P0QZ1Sie"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{"content":"SPECIALIST"},"logprobs":null,"finish_reason":null}],"usage":null,"obfuscation":"cGnJBQBwX"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{"content":":"},"logprobs":null,"finish_reason":null}],"usage":null,"obfuscation":"qOtIXzvm"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{"content":" "},"logprobs":null,"finish_reason":null}],"usage":null,"obfuscation":"fPfIfp9O4"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{"content":"4"},"logprobs":null,"finish_reason":null}],"usage":null,"obfuscation":"Oh8CzMr2d"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"stop"}],"usage":null,"obfuscation":"q1lX"}
+
+            data: {"id":"chatcmpl-CmdAgentTest000000000000000000","object":"chat.completion.chunk","created":1768842358,"model":"gpt-3.5-turbo-0125","service_tier":"default","system_fingerprint":null,"choices":[],"usage":{"prompt_tokens":41,"completion_tokens":4,"total_tokens":45,"prompt_tokens_details":{"cached_tokens":0,"audio_tokens":0},"completion_tokens_details":{"reasoning_tokens":0,"audio_tokens":0,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"obfuscation":"OBW5xAJ5rP"}
+
+            data: [DONE]
+
+        headers: {}
+        status: 200 OK
+        code: 200
+        duration: 1.612958419s

e2e/testdata/command_agent.yaml

@@ -0,0 +1,20 @@
+version: "2"
+
+agents:
+  root:
+    model: openai/gpt-3.5-turbo
+    instruction: |
+      You are the ROOT agent. Whatever you are asked, you must refuse and
+      only reply with the single word: ROOT.
+    sub_agents:
+      - specialist
+    commands:
+      ask:
+        description: Hand the question off to the specialist sub-agent
+        agent: specialist
+
+  specialist:
+    model: openai/gpt-3.5-turbo
+    instruction: |
+      You are the SPECIALIST agent. Answer the user's question directly and
+      concisely. Always prefix your answer with the single word: SPECIALIST.

pkg/js/expand.go

@@ -125,10 +125,12 @@ func (exp *Expander) ExpandCommands(ctx context.Context, cmds types.Commands) ty
 
 	expanded := make(types.Commands, len(cmds))
 	for k, cmd := range cmds {
-		expanded[k] = types.Command{
-			Description: runExpansion(vm, cmd.Description),
-			Instruction: runExpansion(vm, cmd.Instruction),
-		}
+		// Copy the command so non-template fields (e.g. Agent) are preserved,
+		// then expand only the text fields. This keeps the expansion robust if
+		// new fields are added to types.Command.
+		cmd.Description = runExpansion(vm, cmd.Description)
+		cmd.Instruction = runExpansion(vm, cmd.Instruction)
+		expanded[k] = cmd
 	}
 	return expanded
 }

pkg/js/expand_agent_test.go

@@ -0,0 +1,28 @@
+package js
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/docker/docker-agent/pkg/config/types"
+)
+
+// TestExpandCommandsPreservesAgent verifies the agent-switch target survives
+// command expansion. Dropping it makes agent-only slash commands silently run
+// on the root agent instead of handing off to the named sub-agent.
+func TestExpandCommandsPreservesAgent(t *testing.T) {
+	t.Parallel()
+
+	env := testEnvProvider(map[string]string{})
+	expander := NewJsExpander(&env)
+
+	expanded := expander.ExpandCommands(t.Context(), types.Commands{
+		"ask": {
+			Description: "Hand off to the specialist",
+			Agent:       "specialist",
+		},
+	})
+
+	assert.Equal(t, "specialist", expanded["ask"].Agent)
+}