OpenRouter crows; log which model answered each flight

- ChatBrain speaks OpenAI-style chat completions (OpenRouter now)
- CROWS_PROVIDER picks anthropic or openrouter; default model
  openrouter/free; CROWS_MODEL overrides
- Flight log records the model that actually answered
- Token budgets fall back to a length estimate if usage is missing
- start.command reads either key from .env

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UQnSw4RRWp8uqpj3nsnnXF

brain.go

@@ -17,17 +17,69 @@ type Brain interface {
 	Ask(ctx context.Context, system, prompt string) (text string, tokens int, err error)
 }
 
-// NewBrain uses Claude when ANTHROPIC_API_KEY is set, otherwise an offline mock.
+// modelKey lets a brain report which model actually answered a call
+// (routers like openrouter/free pick a different model each time).
+type modelKey struct{}
+
+func withModelSlot(ctx context.Context, slot *string) context.Context {
+	return context.WithValue(ctx, modelKey{}, slot)
+}
+
+func reportModel(ctx context.Context, model string) {
+	if slot, ok := ctx.Value(modelKey{}).(*string); ok && slot != nil {
+		*slot = model
+	}
+}
+
+// NewBrain picks the crows' model from the environment:
+//
+//	CROWS_PROVIDER=openrouter  OPENROUTER_API_KEY  (default model openrouter/free)
+//	CROWS_PROVIDER=anthropic   ANTHROPIC_API_KEY   (default model claude-sonnet-5-5)
+//	CROWS_MODEL overrides the model for either.
+//
+// With no provider set, whichever key is present wins (Anthropic first).
+// No key at all means the offline mock.
 func NewBrain() Brain {
-	key := os.Getenv("ANTHROPIC_API_KEY")
-	if key == "" {
-		return MockBrain{}
+	provider := strings.ToLower(os.Getenv("CROWS_PROVIDER"))
+	anthropicKey, openrouterKey := os.Getenv("ANTHROPIC_API_KEY"), os.Getenv("OPENROUTER_API_KEY")
+	if provider == "" {
+		switch {
+		case anthropicKey != "":
+			provider = "anthropic"
+		case openrouterKey != "":
+			provider = "openrouter"
+		}
 	}
 	model := os.Getenv("CROWS_MODEL")
+	switch provider {
+	case "anthropic":
+		if anthropicKey == "" {
+			fmt.Fprintln(os.Stderr, "CROWS_PROVIDER=anthropic but ANTHROPIC_API_KEY is empty; using the offline mock")
+			return MockBrain{}
+		}
 		if model == "" {
 			model = "claude-sonnet-5-5"
 		}
-	return &AnthropicBrain{key: key, model: model, client: &http.Client{}}
+		return &AnthropicBrain{key: anthropicKey, model: model, client: &http.Client{}}
+	case "openrouter":
+		if openrouterKey == "" {
+			fmt.Fprintln(os.Stderr, "CROWS_PROVIDER=openrouter but OPENROUTER_API_KEY is empty; using the offline mock")
+			return MockBrain{}
+		}
+		if model == "" {
+			model = "openrouter/free"
+		}
+		return &ChatBrain{
+			provider: "OpenRouter", url: "https://openrouter.ai/api/v1/chat/completions",
+			key: openrouterKey, model: model, client: &http.Client{},
+			headers: map[string]string{"X-OpenRouter-Title": "So Many Crows"},
+		}
+	case "":
+		return MockBrain{}
+	default:
+		fmt.Fprintf(os.Stderr, "unknown CROWS_PROVIDER %q; using the offline mock\n", provider)
+		return MockBrain{}
+	}
 }
 
 type AnthropicBrain struct {
@@ -80,9 +132,93 @@ func (b *AnthropicBrain) Ask(ctx context.Context, system, prompt string) (string
 			sb.WriteString(c.Text)
 		}
 	}
+	reportModel(ctx, b.model)
 	return sb.String(), out.Usage.InputTokens + out.Usage.OutputTokens, nil
 }
 
+// ChatBrain speaks the OpenAI-style chat completions format (OpenRouter, and
+// gateways like OpenCode Zen for open models).
+type ChatBrain struct {
+	provider, url, key, model string
+	headers                   map[string]string
+	client                    *http.Client
+}
+
+func (b *ChatBrain) Name() string { return b.provider + " (" + b.model + ")" }
+
+func (b *ChatBrain) Ask(ctx context.Context, system, prompt string) (string, int, error) {
+	body, _ := json.Marshal(map[string]any{
+		"model":      b.model,
+		"max_tokens": 2048,
+		"messages": []map[string]string{
+			{"role": "system", "content": system},
+			{"role": "user", "content": prompt},
+		},
+	})
+	req, err := http.NewRequestWithContext(ctx, "POST", b.url, bytes.NewReader(body))
+	if err != nil {
+		return "", 0, err
+	}
+	req.Header.Set("Authorization", "Bearer "+b.key)
+	req.Header.Set("Content-Type", "application/json")
+	for k, v := range b.headers {
+		req.Header.Set(k, v)
+	}
+	resp, err := b.client.Do(req)
+	if err != nil {
+		return "", 0, err
+	}
+	defer resp.Body.Close()
+	raw, _ := io.ReadAll(io.LimitReader(resp.Body, 4<<20))
+	if resp.StatusCode != http.StatusOK {
+		return "", 0, fmt.Errorf("%s returned %d: %s", b.provider, resp.StatusCode, clip(raw, 300))
+	}
+	var out struct {
+		Model   string `json:"model"`
+		Choices []struct {
+			Message struct {
+				Content string `json:"content"`
+			} `json:"message"`
+		} `json:"choices"`
+		Usage *struct {
+			PromptTokens     int `json:"prompt_tokens"`
+			CompletionTokens int `json:"completion_tokens"`
+		} `json:"usage"`
+		Error *struct {
+			Message string `json:"message"`
+		} `json:"error"`
+	}
+	if err := json.Unmarshal(raw, &out); err != nil {
+		return "", 0, fmt.Errorf("%s sent an unreadable reply: %w", b.provider, err)
+	}
+	if out.Error != nil {
+		return "", 0, fmt.Errorf("%s error: %s", b.provider, out.Error.Message)
+	}
+	if len(out.Choices) == 0 || strings.TrimSpace(out.Choices[0].Message.Content) == "" {
+		return "", 0, fmt.Errorf("%s sent an empty reply", b.provider)
+	}
+	text := out.Choices[0].Message.Content
+	// Budgets must still bite if a provider leaves out usage: estimate ~4 characters per token.
+	tokens := (len(system) + len(prompt) + len(text)) / 4
+	if out.Usage != nil && out.Usage.PromptTokens+out.Usage.CompletionTokens > 0 {
+		tokens = out.Usage.PromptTokens + out.Usage.CompletionTokens
+	}
+	model := out.Model
+	if model == "" {
+		model = b.model
+	}
+	reportModel(ctx, model)
+	return text, tokens, nil
+}
+
+func clip(b []byte, n int) string {
+	s := strings.TrimSpace(string(b))
+	if len(s) > n {
+		return s[:n] + "…"
+	}
+	return s
+}
+
 // MockBrain lets the whole flow run offline with no API key.
 type MockBrain struct{}
 
@@ -92,6 +228,7 @@ func (MockBrain) Ask(ctx context.Context, system, prompt string) (string, int, e
 	if err := ctx.Err(); err != nil {
 		return "", 0, err
 	}
+	reportModel(ctx, "mock")
 	tokens := (len(system)+len(prompt))/4 + 40
 	switch {
 	case strings.Contains(system, markerSentry):

brain_test.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func fakeChat(t *testing.T, status int, reply string) (*ChatBrain, *http.Request) {
+	t.Helper()
+	var got http.Request
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		got = *r
+		var body map[string]any
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			t.Errorf("request body is not JSON: %v", err)
+		}
+		if body["model"] != "openrouter/free" {
+			t.Errorf("model = %v", body["model"])
+		}
+		w.WriteHeader(status)
+		w.Write([]byte(reply))
+	}))
+	t.Cleanup(srv.Close)
+	return &ChatBrain{provider: "OpenRouter", url: srv.URL, key: "k", model: "openrouter/free", client: srv.Client(),
+		headers: map[string]string{"X-OpenRouter-Title": "So Many Crows"}}, &got
+}
+
+func TestChatBrainReply(t *testing.T) {
+	b, req := fakeChat(t, 200, `{"model":"some/model:free","choices":[{"message":{"content":"caw"}}],"usage":{"prompt_tokens":10,"completion_tokens":5}}`)
+	var model string
+	text, tokens, err := b.Ask(withModelSlot(context.Background(), &model), "sys", "hi")
+	if err != nil || text != "caw" || tokens != 15 || model != "some/model:free" {
+		t.Fatalf("got %q %d %q %v", text, tokens, model, err)
+	}
+	if req.Header.Get("Authorization") != "Bearer k" || req.Header.Get("X-OpenRouter-Title") != "So Many Crows" {
+		t.Fatalf("headers: %v", req.Header)
+	}
+}
+
+func TestChatBrainEstimatesTokensWhenUsageMissing(t *testing.T) {
+	b, _ := fakeChat(t, 200, `{"choices":[{"message":{"content":"`+strings.Repeat("a", 400)+`"}}]}`)
+	_, tokens, err := b.Ask(context.Background(), "", "")
+	if err != nil || tokens != 100 {
+		t.Fatalf("tokens = %d, err %v; want the 4-chars-per-token estimate so budgets still bite", tokens, err)
+	}
+}
+
+func TestChatBrainErrors(t *testing.T) {
+	for name, c := range map[string]struct {
+		status int
+		body   string
+		want   string
+	}{
+		"rate limit": {429, `{"error":{"message":"Rate limit exceeded"}}`, "429"},
+		"error body": {200, `{"error":{"message":"no free models"}}`, "no free models"},
+		"empty":      {200, `{"choices":[{"message":{"content":"  "}}]}`, "empty reply"},
+	} {
+		b, _ := fakeChat(t, c.status, c.body)
+		if _, _, err := b.Ask(context.Background(), "s", "p"); err == nil || !strings.Contains(err.Error(), c.want) {
+			t.Errorf("%s: err = %v, want %q", name, err, c.want)
+		}
+	}
+}
+
+func TestNewBrainPicksProvider(t *testing.T) {
+	t.Setenv("ANTHROPIC_API_KEY", "")
+	t.Setenv("OPENROUTER_API_KEY", "or")
+	t.Setenv("CROWS_PROVIDER", "")
+	t.Setenv("CROWS_MODEL", "")
+	if got := NewBrain().Name(); got != "OpenRouter (openrouter/free)" {
+		t.Fatalf("got %q", got)
+	}
+	t.Setenv("CROWS_PROVIDER", "anthropic")
+	if got := NewBrain().Name(); got != "offline mock" {
+		t.Fatalf("anthropic with no key should fall back to mock, got %q", got)
+	}
+}

flightlog.go

@@ -17,6 +17,7 @@ type Event struct {
 	Crow      string    `json:"crow,omitempty"`
 	Mode      string    `json:"mode,omitempty"`
 	TaskType  string    `json:"task_type,omitempty"`
+	Model     string    `json:"model,omitempty"` // which model actually answered (routers vary)
 	Tokens    int       `json:"tokens,omitempty"`
 	Ms        int64     `json:"ms,omitempty"`
 	Verdict   string    `json:"verdict,omitempty"`

flock.go

@@ -144,14 +144,15 @@ func (f *Flock) ask(ctx context.Context, w Watcher, crow, system, prompt string,
 	cctx, cancel := context.WithTimeout(ctx, f.g.CrowTimeout)
 	defer cancel()
 	start := time.Now()
-	text, tokens, err := f.brain.Ask(cctx, system, prompt)
+	var model string
+	text, tokens, err := f.brain.Ask(withModelSlot(cctx, &model), system, prompt)
 	for _, b := range budgets {
 		b.Add(tokens)
 	}
 	if errors.Is(err, context.DeadlineExceeded) {
 		err = fmt.Errorf("%s timed out after %s and was dropped", crow, f.g.CrowTimeout)
 	}
-	e := Event{Kind: "flight", Crow: crow, Tokens: tokens, Ms: time.Since(start).Milliseconds(), Output: text}
+	e := Event{Kind: "flight", Crow: crow, Model: model, Tokens: tokens, Ms: time.Since(start).Milliseconds(), Output: text}
 	if err != nil {
 		e.Error = err.Error()
 	}

start.command

@@ -2,26 +2,27 @@
 # So Many Crows: local server.
 # Double-click to start. Close this window (or Ctrl-C) to stop.
 #
-#   - Real crows (Claude) when .env in this folder holds ANTHROPIC_API_KEY=...; mock crows otherwise.
-#   - `./start.command --mock` forces mock crows.
-#   - Listens on this Mac only (127.0.0.1:8080). State lives in .crows/ (delete it to start fresh).
-#   - Guardrails: 20,000 tokens per item, 100,000 per list; you approve everything until crows earn trust.
+# Which crows fly is set in .env in this folder (never committed):
+#   OPENROUTER_API_KEY=...      OpenRouter (default model: openrouter/free)
+#   ANTHROPIC_API_KEY=...       Claude direct from Anthropic (default: claude-sonnet-5-5)
+#   CROWS_PROVIDER=openrouter   optional: pick one when both keys are present
+#   CROWS_MODEL=...             optional: a specific model
+# `./start.command --mock` forces offline mock crows.
+#
+# Listens on this Mac only (127.0.0.1:8080). State lives in .crows/ (delete it to start fresh).
+# Guardrails: 20,000 tokens per item, 100,000 per list; you approve everything until crows earn trust.
 cd "$(dirname "$0")" || exit 1
 xattr -d com.apple.quarantine ./crows 2>/dev/null
 chmod +x ./crows
 
-unset ANTHROPIC_API_KEY
-if [ "$1" != "--mock" ] && [ -f .env ]; then
-  # Read only the key line; the file is never executed.
-  ANTHROPIC_API_KEY="$(sed -n 's/^ANTHROPIC_API_KEY=//p' .env | head -n 1 | tr -d '[:space:]')"
-  CROWS_MODEL_FROM_ENV="$(sed -n 's/^CROWS_MODEL=//p' .env | head -n 1 | tr -d '[:space:]')"
-  [ -n "$CROWS_MODEL_FROM_ENV" ] && export CROWS_MODEL="$CROWS_MODEL_FROM_ENV"
-  [ -n "$ANTHROPIC_API_KEY" ] && export ANTHROPIC_API_KEY
-fi
-if [ -n "$ANTHROPIC_API_KEY" ]; then
-  echo "Real crows: Claude (${CROWS_MODEL:-claude-sonnet-5-5}). Each list is capped at 100,000 tokens."
-else
-  echo "Mock crows (no key in .env, or --mock)."
+# Read only these lines from .env; the file is never executed.
+envval() { sed -n "s/^$1=//p" .env 2>/dev/null | head -n 1 | tr -d '[:space:]"'; }
+unset ANTHROPIC_API_KEY OPENROUTER_API_KEY CROWS_PROVIDER CROWS_MODEL
+if [ "$1" != "--mock" ]; then
+  for v in ANTHROPIC_API_KEY OPENROUTER_API_KEY CROWS_PROVIDER CROWS_MODEL; do
+    val="$(envval "$v")"
+    [ -n "$val" ] && export "$v=$val"
+  done
 fi
 
 if lsof -iTCP:8080 -sTCP:LISTEN >/dev/null 2>&1; then
@@ -29,4 +30,4 @@ if lsof -iTCP:8080 -sTCP:LISTEN >/dev/null 2>&1; then
   exit 1
 fi
 (sleep 1; open "http://127.0.0.1:8080") &
-exec ./crows serve -addr 127.0.0.1:8080
+exec ./crows serve -addr 127.0.0.1:8080   # prints which brain is flying