fix(llamaswap): address Gadfly review findings

- Unload: reject model ids containing path separators (/?#) so a model name
  can't redirect the request to another endpoint; ":" (common in ids) stays
  verbatim.
- doJSON: take a model arg so image/management HTTP errors carry the target id
  (was always ""); add a base-URL guard so management methods fail clearly
  instead of building a bare-path request; cap the success-path JSON decode with
  io.LimitReader (64 MiB) and drain the body when out is nil for conn reuse.
- image: reject negative Request.N before sending.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

provider/llamaswap/image.go

@@ -51,6 +51,9 @@ func (m *imageModel) Generate(ctx context.Context, req imagegen.Request, opts ..
 	if strings.TrimSpace(req.Prompt) == "" {
 		return nil, fmt.Errorf("%w: image generation requires a prompt", llm.ErrUnsupported)
 	}
+	if req.N < 0 {
+		return nil, fmt.Errorf("%w: image count N must be >= 0, got %d", llm.ErrUnsupported, req.N)
+	}
 
 	wire := imageRequest{
 		Model:          m.id,
@@ -61,7 +64,7 @@ func (m *imageModel) Generate(ctx context.Context, req imagegen.Request, opts ..
 	}
 
 	var resp imageResponse
-	if err := m.p.doJSON(ctx, http.MethodPost, "/v1/images/generations", &wire, &resp); err != nil {
+	if err := m.p.doJSON(ctx, http.MethodPost, "/v1/images/generations", m.id, &wire, &resp); err != nil {
 		return nil, err
 	}
 

provider/llamaswap/llamaswap.go

@@ -38,6 +38,11 @@ import (
 // DefaultName is the registry name used when WithName is not given.
 const DefaultName = "llama-swap"
 
+// maxResponseBytes caps the JSON body read on the success path. Generous
+// enough for a multi-image b64 payload, bounded so a hostile/buggy upstream
+// can't make a decode allocate without limit.
+const maxResponseBytes = 64 << 20
+
 // Provider is a llama-swap client. It satisfies llm.Provider (chat, delegated
 // to provider/openai) and imagegen.Provider (image generation), and exposes
 // llama-swap's management endpoints as concrete methods.
@@ -136,7 +141,7 @@ func (p *Provider) ListModels(ctx context.Context) ([]ModelInfo, error) {
 	var out struct {
 		Data []ModelInfo `json:"data"`
 	}
-	if err := p.doJSON(ctx, http.MethodGet, "/v1/models", nil, &out); err != nil {
+	if err := p.doJSON(ctx, http.MethodGet, "/v1/models", "", nil, &out); err != nil {
 		return nil, err
 	}
 	return out.Data, nil
@@ -148,7 +153,7 @@ func (p *Provider) ListModels(ctx context.Context) ([]ModelInfo, error) {
 // would have to guess.
 func (p *Provider) Running(ctx context.Context) (json.RawMessage, error) {
 	var out json.RawMessage
-	if err := p.doJSON(ctx, http.MethodGet, "/running", nil, &out); err != nil {
+	if err := p.doJSON(ctx, http.MethodGet, "/running", "", nil, &out); err != nil {
 		return nil, err
 	}
 	return out, nil
@@ -160,18 +165,30 @@ func (p *Provider) Running(ctx context.Context) (json.RawMessage, error) {
 func (p *Provider) Unload(ctx context.Context, model string) error {
 	path := "/api/models/unload"
 	if model != "" {
+		// Why reject rather than percent-escape: llama-swap model ids legitimately
+		// contain ":" (e.g. "qwen3:14b"), which is path-legal and must reach the
+		// server verbatim; only path-structure characters are dangerous (they'd
+		// redirect the request to another endpoint), and those never appear in a
+		// real model id.
+		if strings.ContainsAny(model, "/?#") {
+			return fmt.Errorf("llama-swap: invalid model id %q for unload (contains a path separator)", model)
+		}
 		path += "/" + model
 	}
-	return p.doJSON(ctx, http.MethodPost, path, nil, nil)
+	return p.doJSON(ctx, http.MethodPost, path, "", nil, nil)
 }
 
 // --- shared HTTP helper for management + image endpoints ---
 
 // doJSON performs a request to a llama-swap endpoint relative to baseURL,
-// optionally encoding body and decoding into out (either may be nil). Transport
-// failures are wrapped raw so llm.Classify still sees the underlying net error;
-// non-2xx responses become *llm.APIError.
-func (p *Provider) doJSON(ctx context.Context, method, path string, body, out any) error {
+// optionally encoding body and decoding into out (either may be nil). model
+// labels the failing target in any *llm.APIError ("" for endpoints that aren't
+// model-specific). Transport failures are wrapped raw so llm.Classify still
+// sees the underlying net error; non-2xx responses become *llm.APIError.
+func (p *Provider) doJSON(ctx context.Context, method, path, model string, body, out any) error {
+	if p.baseURL == "" {
+		return fmt.Errorf("llama-swap provider %q: no base URL configured (set one via WithBaseURL or an LLM_* env DSN)", p.name)
+	}
 	var rdr io.Reader
 	if body != nil {
 		b, err := json.Marshal(body)
@@ -196,12 +213,15 @@ func (p *Provider) doJSON(ctx context.Context, method, path string, body, out an
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode/100 != 2 {
-		return p.apiError(resp, "")
+		return p.apiError(resp, model)
 	}
 	if out != nil {
-		if err := json.NewDecoder(resp.Body).Decode(out); err != nil {
+		if err := json.NewDecoder(io.LimitReader(resp.Body, maxResponseBytes)).Decode(out); err != nil {
 			return fmt.Errorf("llama-swap: decode response: %w", err)
 		}
+	} else {
+		// Drain (bounded) so the connection can be reused.
+		_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, maxResponseBytes))
 	}
 	return nil
 }

provider/llamaswap/llamaswap_test.go

@@ -127,6 +127,24 @@ func TestUnload(t *testing.T) {
 	if gotPath != "/api/models/unload" {
 		t.Errorf("unload-all path = %q", gotPath)
 	}
+
+	// A model id with a path separator is rejected before any request.
+	if err := p.Unload(context.Background(), "../admin"); err == nil {
+		t.Error("expected error for model id with path separator")
+	}
+}
+
+func TestManagementNoBaseURL(t *testing.T) {
+	p := New() // no base URL
+	if _, err := p.ListModels(context.Background()); err == nil {
+		t.Error("ListModels: expected error for missing base URL")
+	}
+	if _, err := p.Running(context.Background()); err == nil {
+		t.Error("Running: expected error for missing base URL")
+	}
+	if err := p.Unload(context.Background(), "m"); err == nil {
+		t.Error("Unload: expected error for missing base URL")
+	}
 }
 
 func TestRunningRaw(t *testing.T) {