fix(create_project): substitute the whole tree, rename cmd dir, resolve branch (#42)

create_project_from_template returned files_substituted:null and produced a
non-building scaffold. Three root causes, all fixed:

1. Empty branch: /generate omits default_branch, so every SubstituteFile read
   hit an empty ref and 404'd → nothing substituted. Resolve the branch
   explicitly (re-fetch the repo; fall back to "main"). The old unit test hid
   this by mocking default_branch:"main".
2. Incomplete + rename-incapable: substitution ran over a fixed 6-file list
   that missed cmd/__PROJECT_NAME__/main.go and could not rename the
   cmd/__PROJECT_NAME__/ directory. Replace with a recursive tree walk:
   content-substitute every blob, and for any path carrying a placeholder,
   rename it (POST-create new path + delete old).
3. Stale module host: __MODULE_PATH__ used gitea.d-ma.be (the pre-rename host,
   which breaks `go mod download` downstream). Use git.d-ma.be.

Also: fail loud — if nothing was substituted, populate partial_failure instead
of returning silent success (the null that started this).

Tests rewritten to drive the tree-walk flow and assert: cmd/ rename (new path
POST + old path delete), git.d-ma.be module substitution, empty-generate-branch
fallback, and the loud-on-nothing path.

Closes #42.

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

internal/tools/create_project_from_template.go

@@ -2,10 +2,12 @@ package tools
 
 import (
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"regexp"
+	"strings"
 
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
@@ -14,22 +16,22 @@ import (
 
 var nameRe = regexp.MustCompile(`^[a-z][a-z0-9-]{1,38}[a-z0-9]$`)
 
-var substitutionFiles = []string{
-	"go.mod",
-	"Taskfile.yml",
-	"Dockerfile",
-	".gitea/workflows/cd.yml",
-	"README.md",
-	".context/PROJECT.md",
-}
-
 func substitutions(owner, name string) map[string]string {
 	return map[string]string{
 		"__PROJECT_NAME__": name,
-		"__MODULE_PATH__":  "gitea.d-ma.be/" + owner + "/" + name,
+		// git.d-ma.be is the canonical module host (the gitea.d-ma.be → git.d-ma.be
+		// rename; a stale host breaks `go mod download` for downstream consumers).
+		"__MODULE_PATH__": "git.d-ma.be/" + owner + "/" + name,
 	}
 }
 
+func applyReplacements(s string, repls map[string]string) string {
+	for k, v := range repls {
+		s = strings.ReplaceAll(s, k, v)
+	}
+	return s
+}
+
 // CreateProjectFromTemplate is the exported type so tests can reference it.
 type CreateProjectFromTemplate struct {
 	c             *gitea.Client
@@ -45,7 +47,7 @@ func NewCreateProjectFromTemplate(c *gitea.Client, a *allowlist.Allowlist, tmplO
 func (t *CreateProjectFromTemplate) Descriptor() registry.ToolDescriptor {
 	return registry.ToolDescriptor{
 		Name:        "create_project_from_template",
-		Description: "Create a new project repo from a template, applying placeholder substitutions to known files. Defaults to the server-configured template; pass template_name to override (e.g. template-go-agent).",
+		Description: "Create a new project repo from a template, substituting placeholders (__PROJECT_NAME__, __MODULE_PATH__) in every file's content AND path (e.g. renaming cmd/__PROJECT_NAME__/) so the result builds. Defaults to the server-configured template; pass template_name to override (e.g. template-go-agent).",
 		InputSchema: json.RawMessage(`{
 			"type":"object",
 			"properties":{
@@ -135,21 +137,105 @@ func (t *CreateProjectFromTemplate) Call(ctx context.Context, raw json.RawMessag
 		DefaultBranch: newRepo.DefaultBranch,
 	}
 
-	// Substitute placeholders in known files (best-effort).
-	repls := substitutions(args.Owner, args.Name)
+	// The /generate response often omits default_branch — resolve it explicitly,
+	// otherwise every file read below hits an empty ref and nothing substitutes
+	// (the silent-null bug: gitea-mcp#42).
 	branch := newRepo.DefaultBranch
-	for _, path := range substitutionFiles {
-		if err := t.c.SubstituteFile(ctx, args.Owner, args.Name, branch, path, repls); err != nil {
-			// Files that don't exist in this template are silently skipped.
-			if errors.Is(err, gitea.ErrNotFound) {
-				continue
-			}
-			// Any other error halts the substitution pass with partial_failure recorded.
-			result.PartialFailure = fmt.Sprintf("%s: %v", path, err)
+	if branch == "" {
+		if r, gerr := t.c.GetRepo(ctx, args.Owner, args.Name); gerr == nil && r.DefaultBranch != "" {
+			branch = r.DefaultBranch
+		} else {
+			branch = "main"
+		}
+	}
+	result.DefaultBranch = branch
+
+	// Substitute across the WHOLE tree: content in every blob, plus a path rename
+	// for any file whose path carries a placeholder (e.g. cmd/__PROJECT_NAME__/main.go).
+	// A fixed known-files list can't rename directories or cover every templated
+	// file, which is why the old scaffold didn't build.
+	repls := substitutions(args.Owner, args.Name)
+	tree, err := t.c.GetTree(ctx, args.Owner, args.Name, branch, true)
+	if err != nil {
+		result.PartialFailure = fmt.Sprintf("tree walk (%s@%s): %v", args.Name, branch, err)
+		return textOK(result)
+	}
+
+	for _, e := range tree.Tree {
+		if e.Type != "blob" {
+			continue
+		}
+		substituted, fail := t.substituteEntry(ctx, args.Owner, args.Name, branch, e.Path, repls)
+		if fail != "" {
+			result.PartialFailure = fail
 			break
 		}
-		result.FilesSubstituted = append(result.FilesSubstituted, path)
+		if substituted != "" {
+			result.FilesSubstituted = append(result.FilesSubstituted, substituted)
+		}
+	}
+
+	// Fail loud: a scaffold that still holds placeholders does not build. Nothing
+	// substituted (with no explicit failure) means the walk found no placeholders —
+	// suspicious for a real template. Surface it instead of returning silent success.
+	if result.PartialFailure == "" && len(result.FilesSubstituted) == 0 {
+		result.PartialFailure = fmt.Sprintf("no placeholders substituted in %s@%s — verify the scaffold is not left templated", args.Name, branch)
 	}
 
 	return textOK(result)
 }
+
+// substituteEntry substitutes placeholders in one blob. If the path carries a
+// placeholder it renames the file (write new + delete old); otherwise it rewrites
+// content in place when changed. Returns a human-readable description of what was
+// substituted ("" if nothing), and a non-empty partial-failure string on error.
+func (t *CreateProjectFromTemplate) substituteEntry(ctx context.Context, owner, name, branch, path string, repls map[string]string) (substituted, failure string) {
+	newPath := applyReplacements(path, repls)
+
+	fc, err := t.c.GetFileContents(ctx, owner, name, path, branch)
+	if err != nil {
+		if errors.Is(err, gitea.ErrNotFound) {
+			return "", "" // vanished between tree walk and read; skip
+		}
+		return "", fmt.Sprintf("read %s: %v", path, err)
+	}
+	decoded, err := base64.StdEncoding.DecodeString(fc.Content)
+	if err != nil {
+		return "", fmt.Sprintf("decode %s: %v", path, err)
+	}
+	newContent := applyReplacements(string(decoded), repls)
+	renamed := newPath != path
+	changed := newContent != string(decoded)
+	if !renamed && !changed {
+		return "", "" // nothing to do
+	}
+	enc := base64.StdEncoding.EncodeToString([]byte(newContent))
+
+	if renamed {
+		if _, err := t.c.UpsertFile(ctx, owner, name, newPath, gitea.UpsertFileArgs{
+			Branch:  branch,
+			Content: enc,
+			Message: fmt.Sprintf("template: substitute + rename %s -> %s", path, newPath),
+		}); err != nil {
+			return "", fmt.Sprintf("write %s: %v", newPath, err)
+		}
+		if _, err := t.c.DeleteFile(ctx, owner, name, path, gitea.DeleteFileArgs{
+			Branch:  branch,
+			Sha:     fc.Sha,
+			Message: fmt.Sprintf("template: drop placeholder path %s", path),
+		}); err != nil {
+			return "", fmt.Sprintf("delete %s: %v", path, err)
+		}
+		return path + " -> " + newPath, ""
+	}
+
+	if _, err := t.c.UpsertFile(ctx, owner, name, path, gitea.UpsertFileArgs{
+		Branch:  branch,
+		Content: enc,
+		Message: "template: substitute placeholders",
+		Sha:     fc.Sha,
+	}); err != nil {
+		return "", fmt.Sprintf("write %s: %v", path, err)
+	}
+	return path, ""
+}

internal/tools/create_project_from_template_test.go

@@ -5,9 +5,11 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"strings"
+	"sync"
 	"testing"
 
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
@@ -17,306 +19,262 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// substitutionFileList matches the tool's internal list — used to drive fake server routing.
-var substitutionFileList = []string{
-	"go.mod",
-	"Taskfile.yml",
-	"Dockerfile",
-	".gitea/workflows/cd.yml",
-	"README.md",
-	".context/PROJECT.md",
-}
+func encb64(s string) string { return base64.StdEncoding.EncodeToString([]byte(s)) }
 
-// contentWithPlaceholder is a template file body that contains the placeholder.
-const contentWithPlaceholder = "# __PROJECT_NAME__\nmodule __MODULE_PATH__\n"
-
-func encodedContent(s string) string {
-	return base64.StdEncoding.EncodeToString([]byte(s))
-}
-
-// fileContentsJSON returns a JSON FileContents object for the given path.
-func fileContentsJSON(path string) string {
-	enc := encodedContent(contentWithPlaceholder)
-	return fmt.Sprintf(`{"path":%q,"sha":"sha-%s","size":40,"content":%q,"encoding":"base64"}`,
-		path, strings.ReplaceAll(path, "/", "-"), enc)
-}
-
-// fileWriteResultJSON returns a minimal FileWriteResult JSON.
-func fileWriteResultJSON(path string) string {
-	return fmt.Sprintf(`{"content":{"path":%q,"sha":"newsha","html_url":""},"commit":{"sha":"c","html_url":""}}`, path)
-}
-
-// newTemplateRepoJSON returns a JSON Repo marked as template.
-func newTemplateRepoJSON(name string, isTemplate bool) string {
-	return fmt.Sprintf(`{"name":%q,"full_name":"mathias/%s","default_branch":"main","description":"","private":false,"clone_url":"http://gitea.example.com/mathias/%s.git","html_url":"http://gitea.example.com/mathias/%s","template":%v}`,
+func templateRepoJSON(name string, isTemplate bool) string {
+	return fmt.Sprintf(`{"name":%q,"full_name":"mathias/%s","default_branch":"main","clone_url":"http://gitea.example.com/mathias/%s.git","html_url":"http://gitea.example.com/mathias/%s","template":%v}`,
 		name, name, name, name, isTemplate)
 }
 
-// newGeneratedRepoJSON returns the JSON for the newly generated repo.
-func newGeneratedRepoJSON(name string) string {
-	return fmt.Sprintf(`{"name":%q,"full_name":"mathias/%s","default_branch":"main","description":"","private":false,"clone_url":"http://gitea.example.com/mathias/%s.git","html_url":"http://gitea.example.com/mathias/%s","template":false}`,
-		name, name, name, name)
+// fakeTemplateServer serves the whole create-from-template flow off an in-memory
+// file map, driving the tool's tree-walk. Records writes/deletes/put-bodies.
+type fakeTemplateServer struct {
+	mu           sync.Mutex
+	files        map[string]string // path -> raw (un-substituted) content
+	genBranch    string            // default_branch returned by /generate ("" to force fallback)
+	generated    bool
+	puts         []string
+	deletes      []string
+	putBodies    map[string]string // path -> decoded written content
+	repoGetsPost int               // GET dest after generate (branch fallback)
 }
 
-func newCreateProjectTool(srvURL string) *tools.CreateProjectFromTemplate {
-	c := gitea.NewClient(srvURL, "tok")
-	a := allowlist.New([]string{"mathias"})
-	return tools.NewCreateProjectFromTemplate(c, a, "mathias", "template-go-web")
+func newFakeTemplateServer(files map[string]string, genBranch string) *fakeTemplateServer {
+	return &fakeTemplateServer{files: files, genBranch: genBranch, putBodies: map[string]string{}}
 }
 
-// TestCreateProjectHappyPath: all 6 files served and substituted.
-func TestCreateProjectHappyPath(t *testing.T) {
-	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+func (f *fakeTemplateServer) handler(t *testing.T, tmpl, dest string) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		f.mu.Lock()
+		defer f.mu.Unlock()
 		w.Header().Set("Content-Type", "application/json")
+		p := r.URL.Path
+
 		switch {
-		// Template repo lookup
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-web":
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-web", true)))
+		case r.Method == http.MethodGet && p == "/api/v1/repos/mathias/"+tmpl:
+			_, _ = w.Write([]byte(templateRepoJSON(tmpl, true)))
 
-		// Destination repo lookup — 404 means it doesn't exist yet
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/new-svc":
-			w.WriteHeader(http.StatusNotFound)
-			_, _ = w.Write([]byte(`{"message":"not found"}`))
+		case r.Method == http.MethodGet && p == "/api/v1/repos/mathias/"+dest:
+			if !f.generated {
+				w.WriteHeader(http.StatusNotFound)
+				_, _ = w.Write([]byte(`{"message":"not found"}`))
+				return
+			}
+			f.repoGetsPost++
+			_, _ = w.Write([]byte(fmt.Sprintf(`{"name":%q,"full_name":"mathias/%s","default_branch":"main","clone_url":"c","html_url":"h","template":false}`, dest, dest)))
 
-		// Generate
-		case r.Method == http.MethodPost && r.URL.Path == "/api/v1/repos/mathias/template-go-web/generate":
+		case r.Method == http.MethodPost && p == "/api/v1/repos/mathias/"+tmpl+"/generate":
+			f.generated = true
 			w.WriteHeader(http.StatusCreated)
-			_, _ = w.Write([]byte(newGeneratedRepoJSON("new-svc")))
+			_, _ = w.Write([]byte(fmt.Sprintf(`{"name":%q,"full_name":"mathias/%s","default_branch":%q,"clone_url":"http://gitea.example.com/mathias/%s.git","html_url":"http://gitea.example.com/mathias/%s","template":false}`,
+				dest, dest, f.genBranch, dest, dest)))
 
-		// File contents GET — handle all 6 substitution files
-		case r.Method == http.MethodGet && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/")
-			_, _ = w.Write([]byte(fileContentsJSON(filePath)))
+		case r.Method == http.MethodGet && strings.HasPrefix(p, "/api/v1/repos/mathias/"+dest+"/git/trees/"):
+			var entries []string
+			for path := range f.files {
+				entries = append(entries, fmt.Sprintf(`{"path":%q,"type":"blob","sha":"sha-%s"}`, path, strings.ReplaceAll(path, "/", "-")))
+			}
+			// include a tree (directory) entry to exercise the blob filter
+			entries = append(entries, `{"path":"cmd","type":"tree","sha":"treesha"}`)
+			_, _ = w.Write([]byte(fmt.Sprintf(`{"sha":"root","tree":[%s],"truncated":false}`, strings.Join(entries, ","))))
 
-		// File contents PUT — handle all 6 substitution files
-		case r.Method == http.MethodPut && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/")
+		case r.Method == http.MethodGet && strings.HasPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/"):
+			path := strings.TrimPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/")
+			body, ok := f.files[path]
+			if !ok {
+				w.WriteHeader(http.StatusNotFound)
+				_, _ = w.Write([]byte(`{"message":"not found"}`))
+				return
+			}
+			_, _ = w.Write([]byte(fmt.Sprintf(`{"path":%q,"sha":"sha-%s","size":1,"content":%q,"encoding":"base64"}`,
+				path, strings.ReplaceAll(path, "/", "-"), encb64(body))))
+
+		// POST = create (new/renamed file, no sha), PUT = update (existing, with sha).
+		case (r.Method == http.MethodPost || r.Method == http.MethodPut) && strings.HasPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/"):
+			path := strings.TrimPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/")
+			raw, _ := io.ReadAll(r.Body)
+			var args struct {
+				Content string `json:"content"`
+			}
+			_ = json.Unmarshal(raw, &args)
+			dec, _ := base64.StdEncoding.DecodeString(args.Content)
+			f.puts = append(f.puts, path)
+			f.putBodies[path] = string(dec)
+			if r.Method == http.MethodPost {
+				w.WriteHeader(http.StatusCreated)
+			} else {
+				w.WriteHeader(http.StatusOK)
+			}
+			_, _ = w.Write([]byte(`{"content":{"path":"x","sha":"n"},"commit":{"sha":"c"}}`))
+
+		case r.Method == http.MethodDelete && strings.HasPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/"):
+			path := strings.TrimPrefix(p, "/api/v1/repos/mathias/"+dest+"/contents/")
+			f.deletes = append(f.deletes, path)
 			w.WriteHeader(http.StatusOK)
-			_, _ = w.Write([]byte(fileWriteResultJSON(filePath)))
+			_, _ = w.Write([]byte(`{"content":null,"commit":{"sha":"c"}}`))
 
 		default:
-			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+			t.Errorf("unexpected request: %s %s", r.Method, p)
 			w.WriteHeader(http.StatusNotFound)
 		}
-	}))
+	}
+}
+
+func newTool(srvURL, tmpl string) *tools.CreateProjectFromTemplate {
+	return tools.NewCreateProjectFromTemplate(
+		gitea.NewClient(srvURL, "tok"), allowlist.New([]string{"mathias"}), "mathias", tmpl)
+}
+
+func callTool(t *testing.T, srvURL, tmpl, argsJSON string) createOut {
+	t.Helper()
+	res, err := newTool(srvURL, tmpl).Call(context.Background(), json.RawMessage(argsJSON))
+	require.NoError(t, err)
+	var out createOut
+	require.NoError(t, json.Unmarshal(res, &out))
+	return out
+}
+
+type createOut struct {
+	FullName         string   `json:"full_name"`
+	DefaultBranch    string   `json:"default_branch"`
+	FilesSubstituted []string `json:"files_substituted"`
+	PartialFailure   string   `json:"partial_failure,omitempty"`
+}
+
+// Happy path: whole-tree substitution, content + path rename, correct module host.
+func TestCreateProject_TreeWalk_SubstitutesAndRenames(t *testing.T) {
+	files := map[string]string{
+		"go.mod":                       "module __MODULE_PATH__\n\ngo 1.26\n",
+		"README.md":                    "# __PROJECT_NAME__\n",
+		"cmd/__PROJECT_NAME__/main.go": "package main\nimport \"__MODULE_PATH__/pkg/litellm\"\nconst n = \"__PROJECT_NAME__\"\n",
+		"pkg/litellm/x.go":             "package litellm\n", // no placeholder → untouched
+	}
+	f := newFakeTemplateServer(files, "main")
+	srv := httptest.NewServer(f.handler(t, "template-go-agent", "new-svc"))
 	defer srv.Close()
 
-	tool := newCreateProjectTool(srv.URL)
-	result, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc","description":"A new service"}`))
-	require.NoError(t, err)
+	out := callTool(t, srv.URL, "template-go-agent", `{"owner":"mathias","name":"new-svc"}`)
 
-	var out struct {
-		FullName         string   `json:"full_name"`
-		HTMLURL          string   `json:"html_url"`
-		CloneURL         string   `json:"clone_url"`
-		DefaultBranch    string   `json:"default_branch"`
-		FilesSubstituted []string `json:"files_substituted"`
-		PartialFailure   string   `json:"partial_failure,omitempty"`
-	}
-	require.NoError(t, json.Unmarshal(result, &out))
-
-	assert.Equal(t, "mathias/new-svc", out.FullName)
-	assert.Equal(t, "http://gitea.example.com/mathias/new-svc", out.HTMLURL)
 	assert.Equal(t, "main", out.DefaultBranch)
-	assert.ElementsMatch(t, substitutionFileList, out.FilesSubstituted)
+	assert.Empty(t, out.PartialFailure)
+
+	// content-substituted files present; untouched file absent
+	assert.Contains(t, out.FilesSubstituted, "go.mod")
+	assert.Contains(t, out.FilesSubstituted, "README.md")
+	assert.NotContains(t, out.FilesSubstituted, "pkg/litellm/x.go")
+	// path rename recorded as "old -> new"
+	assert.Contains(t, out.FilesSubstituted, "cmd/__PROJECT_NAME__/main.go -> cmd/new-svc/main.go")
+
+	// module host substituted correctly (git.d-ma.be, not gitea.d-ma.be)
+	assert.Equal(t, "module git.d-ma.be/mathias/new-svc\n\ngo 1.26\n", f.putBodies["go.mod"])
+	// rename: new path written, old path deleted
+	assert.Contains(t, f.puts, "cmd/new-svc/main.go")
+	assert.Contains(t, f.deletes, "cmd/__PROJECT_NAME__/main.go")
+	assert.Equal(t, "package main\nimport \"git.d-ma.be/mathias/new-svc/pkg/litellm\"\nconst n = \"new-svc\"\n",
+		f.putBodies["cmd/new-svc/main.go"])
+	// the untouched file was never written
+	assert.NotContains(t, f.puts, "pkg/litellm/x.go")
+}
+
+// The /generate response omits default_branch (the live gitea behavior the old
+// mock hid) → tool must re-fetch the repo and still substitute.
+func TestCreateProject_EmptyGenerateBranch_FallsBack(t *testing.T) {
+	files := map[string]string{"go.mod": "module __MODULE_PATH__\n"}
+	f := newFakeTemplateServer(files, "") // generate returns default_branch:""
+	srv := httptest.NewServer(f.handler(t, "template-go-agent", "new-svc"))
+	defer srv.Close()
+
+	out := callTool(t, srv.URL, "template-go-agent", `{"owner":"mathias","name":"new-svc"}`)
+
+	assert.Equal(t, "main", out.DefaultBranch, "must resolve branch via GetRepo fallback")
+	assert.GreaterOrEqual(t, f.repoGetsPost, 1, "must re-fetch repo to resolve empty default_branch")
+	assert.Contains(t, out.FilesSubstituted, "go.mod")
+	assert.Equal(t, "module git.d-ma.be/mathias/new-svc\n", f.putBodies["go.mod"])
 	assert.Empty(t, out.PartialFailure)
 }
 
-// TestCreateProjectTemplateNameOverride (issue #24): per-call template_name overrides the
-// server-configured default, so the same binary can generate from template-go-web or
-// template-go-agent without restart.
-func TestCreateProjectTemplateNameOverride(t *testing.T) {
-	var templateLookups, generateCalls []string
+// Fail loud: a template whose files carry no placeholders yields nothing
+// substituted — surface it rather than returning silent success.
+func TestCreateProject_NothingSubstituted_IsLoud(t *testing.T) {
+	files := map[string]string{"README.md": "# static, no placeholders\n"}
+	f := newFakeTemplateServer(files, "main")
+	srv := httptest.NewServer(f.handler(t, "template-go-agent", "new-svc"))
+	defer srv.Close()
 
+	out := callTool(t, srv.URL, "template-go-agent", `{"owner":"mathias","name":"new-svc"}`)
+	assert.Empty(t, out.FilesSubstituted)
+	assert.NotEmpty(t, out.PartialFailure, "nothing substituted must not be silent success")
+}
+
+// Write failure mid-pass → partial_failure populated, no Go error.
+func TestCreateProject_WriteFailure_PartialFailure(t *testing.T) {
+	files := map[string]string{"go.mod": "module __MODULE_PATH__\n"}
+	f := newFakeTemplateServer(files, "main")
+	base := f.handler(t, "template-go-agent", "new-svc")
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		switch {
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-agent":
-			templateLookups = append(templateLookups, "template-go-agent")
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-agent", true)))
-
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-web":
-			templateLookups = append(templateLookups, "template-go-web")
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-web", true)))
-
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/new-agent":
-			w.WriteHeader(http.StatusNotFound)
-			_, _ = w.Write([]byte(`{"message":"not found"}`))
-
-		case r.Method == http.MethodPost && strings.HasSuffix(r.URL.Path, "/generate"):
-			generateCalls = append(generateCalls, r.URL.Path)
-			w.WriteHeader(http.StatusCreated)
-			_, _ = w.Write([]byte(newGeneratedRepoJSON("new-agent")))
-
-		case r.Method == http.MethodGet && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-agent/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-agent/contents/")
-			_, _ = w.Write([]byte(fileContentsJSON(filePath)))
-
-		case r.Method == http.MethodPut && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-agent/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-agent/contents/")
-			w.WriteHeader(http.StatusOK)
-			_, _ = w.Write([]byte(fileWriteResultJSON(filePath)))
-
-		default:
-			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
-			w.WriteHeader(http.StatusNotFound)
+		if r.Method == http.MethodPut && strings.Contains(r.URL.Path, "/contents/go.mod") {
+			w.WriteHeader(http.StatusInternalServerError)
+			_, _ = w.Write([]byte(`{"message":"boom"}`))
+			return
 		}
+		base(w, r)
 	}))
 	defer srv.Close()
 
-	// Server is configured with template-go-web as the default; call overrides to template-go-agent.
-	tool := newCreateProjectTool(srv.URL)
-	_, err := tool.Call(context.Background(), json.RawMessage(
-		`{"owner":"mathias","name":"new-agent","template_name":"template-go-agent"}`,
-	))
-	require.NoError(t, err)
-
-	assert.Equal(t, []string{"template-go-agent"}, templateLookups,
-		"override must direct the template lookup, not the server default")
-	require.Len(t, generateCalls, 1)
-	assert.Equal(t, "/api/v1/repos/mathias/template-go-agent/generate", generateCalls[0],
-		"override must direct the /generate call too")
+	out := callTool(t, srv.URL, "template-go-agent", `{"owner":"mathias","name":"new-svc"}`)
+	assert.NotEmpty(t, out.PartialFailure)
+	assert.Contains(t, out.PartialFailure, "go.mod")
 }
 
-// TestCreateProjectNameRegexFailure: invalid name returns ErrValidation without hitting network.
-func TestCreateProjectNameRegexFailure(t *testing.T) {
-	tool := tools.NewCreateProjectFromTemplate(
-		gitea.NewClient("http://unused", ""),
-		allowlist.New([]string{"mathias"}),
-		"mathias", "template-go-web",
-	)
-	_, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"INVALID_NAME"}`))
+// ── guardrails unchanged by the rewrite ──────────────────────────────────────
+
+func TestCreateProject_NameRegexFailure(t *testing.T) {
+	_, err := tools.NewCreateProjectFromTemplate(
+		gitea.NewClient("http://unused", ""), allowlist.New([]string{"mathias"}), "mathias", "template-go-agent",
+	).Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"INVALID_NAME"}`))
 	require.Error(t, err)
 	assert.ErrorIs(t, err, gitea.ErrValidation)
 }
 
-// TestCreateProjectAllowlistRejects: owner not in allowlist returns error.
-func TestCreateProjectAllowlistRejects(t *testing.T) {
-	tool := tools.NewCreateProjectFromTemplate(
-		gitea.NewClient("http://unused", ""),
-		allowlist.New([]string{"mathias"}),
-		"mathias", "template-go-web",
-	)
-	_, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"evil","name":"new-svc"}`))
+func TestCreateProject_AllowlistRejects(t *testing.T) {
+	_, err := tools.NewCreateProjectFromTemplate(
+		gitea.NewClient("http://unused", ""), allowlist.New([]string{"mathias"}), "mathias", "template-go-agent",
+	).Call(context.Background(), json.RawMessage(`{"owner":"evil","name":"new-svc"}`))
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "allowlist")
 }
 
-// TestCreateProjectTemplateNotTemplate: template repo exists but is not marked as template.
-func TestCreateProjectTemplateNotTemplate(t *testing.T) {
+func TestCreateProject_NotTemplate(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
-		// Template lookup returns a non-template repo.
-		if r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-web" {
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-web", false)))
+		if r.URL.Path == "/api/v1/repos/mathias/template-go-agent" {
+			_, _ = w.Write([]byte(templateRepoJSON("template-go-agent", false)))
 			return
 		}
 		t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
 		w.WriteHeader(http.StatusNotFound)
 	}))
 	defer srv.Close()
-
-	tool := newCreateProjectTool(srv.URL)
-	_, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc"}`))
+	_, err := newTool(srv.URL, "template-go-agent").Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc"}`))
 	require.Error(t, err)
 	assert.ErrorIs(t, err, gitea.ErrValidation)
 }
 
-// TestCreateProjectDestinationExists: destination repo already exists.
-func TestCreateProjectDestinationExists(t *testing.T) {
+func TestCreateProject_DestinationExists(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
-		switch {
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-web":
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-web", true)))
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/new-svc":
-			// Destination exists — return 200.
-			_, _ = w.Write([]byte(newTemplateRepoJSON("new-svc", false)))
+		switch r.URL.Path {
+		case "/api/v1/repos/mathias/template-go-agent":
+			_, _ = w.Write([]byte(templateRepoJSON("template-go-agent", true)))
+		case "/api/v1/repos/mathias/new-svc":
+			_, _ = w.Write([]byte(templateRepoJSON("new-svc", false)))
 		default:
 			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
 			w.WriteHeader(http.StatusNotFound)
 		}
 	}))
 	defer srv.Close()
-
-	tool := newCreateProjectTool(srv.URL)
-	_, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc"}`))
+	_, err := newTool(srv.URL, "template-go-agent").Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc"}`))
 	require.Error(t, err)
 	assert.ErrorIs(t, err, gitea.ErrConflict)
 }
-
-// TestCreateProjectMidPassSubstitutionFailure: the 4th file (.gitea/workflows/cd.yml) PUT fails;
-// the first 3 are substituted, partial_failure is populated, no Go error is returned.
-func TestCreateProjectMidPassSubstitutionFailure(t *testing.T) {
-	// Files that should succeed (index 0-2 in substitutionFileList).
-	successFiles := map[string]bool{
-		"go.mod":       true,
-		"Taskfile.yml": true,
-		"Dockerfile":   true,
-	}
-	// The 4th file (index 3) is .gitea/workflows/cd.yml — its PUT returns 500.
-	failFile := ".gitea/workflows/cd.yml"
-
-	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		switch {
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/template-go-web":
-			_, _ = w.Write([]byte(newTemplateRepoJSON("template-go-web", true)))
-
-		case r.Method == http.MethodGet && r.URL.Path == "/api/v1/repos/mathias/new-svc":
-			w.WriteHeader(http.StatusNotFound)
-			_, _ = w.Write([]byte(`{"message":"not found"}`))
-
-		case r.Method == http.MethodPost && r.URL.Path == "/api/v1/repos/mathias/template-go-web/generate":
-			w.WriteHeader(http.StatusCreated)
-			_, _ = w.Write([]byte(newGeneratedRepoJSON("new-svc")))
-
-		case r.Method == http.MethodGet && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/")
-			_, _ = w.Write([]byte(fileContentsJSON(filePath)))
-
-		case r.Method == http.MethodPut && strings.HasPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/"):
-			filePath := strings.TrimPrefix(r.URL.Path, "/api/v1/repos/mathias/new-svc/contents/")
-			if filePath == failFile {
-				// Simulate upstream 500.
-				w.WriteHeader(http.StatusInternalServerError)
-				_, _ = w.Write([]byte(`{"message":"internal server error"}`))
-				return
-			}
-			if !successFiles[filePath] {
-				t.Errorf("unexpected PUT for file: %s", filePath)
-				w.WriteHeader(http.StatusNotFound)
-				return
-			}
-			w.WriteHeader(http.StatusOK)
-			_, _ = w.Write([]byte(fileWriteResultJSON(filePath)))
-
-		default:
-			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
-			w.WriteHeader(http.StatusNotFound)
-		}
-	}))
-	defer srv.Close()
-
-	tool := newCreateProjectTool(srv.URL)
-	result, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"mathias","name":"new-svc"}`))
-	// Best-effort: no Go error returned, partial state in result.
-	require.NoError(t, err)
-
-	var out struct {
-		FullName         string   `json:"full_name"`
-		FilesSubstituted []string `json:"files_substituted"`
-		PartialFailure   string   `json:"partial_failure,omitempty"`
-	}
-	require.NoError(t, json.Unmarshal(result, &out))
-
-	// First 3 files should be in FilesSubstituted.
-	assert.Len(t, out.FilesSubstituted, 3)
-	assert.Contains(t, out.FilesSubstituted, "go.mod")
-	assert.Contains(t, out.FilesSubstituted, "Taskfile.yml")
-	assert.Contains(t, out.FilesSubstituted, "Dockerfile")
-	assert.NotContains(t, out.FilesSubstituted, failFile)
-
-	// partial_failure should be non-empty.
-	assert.NotEmpty(t, out.PartialFailure, "partial_failure should be populated on mid-pass failure")
-}