feat(repo_update): tool for archiving + metadata patches

Adds a repo_update tool exposing PATCH /api/v1/repos/{owner}/{name}
with optional pointer fields (archived, description, private,
website, template). Only fields set by the caller are sent on the
wire, so the server patches exactly what was asked for.

Originally needed to archive ingestion-svc cleanly instead of
leaving a README tombstone, and to flip template-go-{agent,web}
to template=true so create_project_from_template stops failing
the "is not marked as template" guard.

Wire-level enforcement of "at least one field" returns ErrValidation
before any network call, preventing no-op PATCHes.

private=false (making a repo public) is allowed but flagged in the
tool description with a "verify intent before calling" warning.
The earlier issue draft suggested an ntfy confirmation hook for
that path — out of scope for this PR; the warning string is the
minimum that fits inside the tool surface today.

Wires NewRepoUpdate into cmd/gitea-mcp/main.go alongside the rest
of the repo_* family.

Closes #12

.aider.conventions.md

@@ -36,9 +36,6 @@ These rules apply to every task across every project, regardless of harness.
 4. **Goal-driven execution.** Define clear success criteria up front for every task.
    Loop — implement, verify, refine — until those criteria are met. Don't claim
    completion without evidence (tests pass, command output, observed behavior).
-5. **Branch-per-task for multi-agent repos.** When another agent may be active on
-   the same repo, create a branch (`agent/<description>`), commit there, and open a
-   PR. Do not merge without explicit instruction from Mathias.
 
 ## Default stack
 
@@ -49,7 +46,7 @@ These rules apply to every task across every project, regardless of harness.
 | Build | Task (taskfile.dev) | Make | — |
 | Containers | Docker Compose (dev), k3s (prod) | — | — |
 | DB | PostgreSQL + sqlc | SQLite | — |
-| Search | Qdrant (vector), BM25 | — | — |
+| Search | pgvector (vector), BM25 | Qdrant (when >1M vectors or hybrid retrieval) | — |
 | Logging | slog (structured) | — | — |
 | Testing | Table-driven, testify | — | — |
 
@@ -71,7 +68,7 @@ Three machines on Tailscale:
 
 | Machine | Role | Key specs |
 |---------|------|-----------|
-| koala | GPU inference, heavy compute | RTX 5070, runs llama-swap, Qdrant |
+| koala | GPU inference, heavy compute | RTX 5070, runs k3s + llama-swap + shared postgres18/pgvector |
 | iguana | Services, builds | M2 Ultra Mac |
 | flamingo | Daily driver, edge | Mac mini, ~/dev is here |
 

.context/system-prompt.txt

@@ -41,9 +41,6 @@ These rules apply to every task across every project, regardless of harness.
 4. **Goal-driven execution.** Define clear success criteria up front for every task.
    Loop — implement, verify, refine — until those criteria are met. Don't claim
    completion without evidence (tests pass, command output, observed behavior).
-5. **Branch-per-task for multi-agent repos.** When another agent may be active on
-   the same repo, create a branch (`agent/<description>`), commit there, and open a
-   PR. Do not merge without explicit instruction from Mathias.
 
 ## Default stack
 
@@ -54,7 +51,7 @@ These rules apply to every task across every project, regardless of harness.
 | Build | Task (taskfile.dev) | Make | — |
 | Containers | Docker Compose (dev), k3s (prod) | — | — |
 | DB | PostgreSQL + sqlc | SQLite | — |
-| Search | Qdrant (vector), BM25 | — | — |
+| Search | pgvector (vector), BM25 | Qdrant (when >1M vectors or hybrid retrieval) | — |
 | Logging | slog (structured) | — | — |
 | Testing | Table-driven, testify | — | — |
 
@@ -76,7 +73,7 @@ Three machines on Tailscale:
 
 | Machine | Role | Key specs |
 |---------|------|-----------|
-| koala | GPU inference, heavy compute | RTX 5070, runs llama-swap, Qdrant |
+| koala | GPU inference, heavy compute | RTX 5070, runs k3s + llama-swap + shared postgres18/pgvector |
 | iguana | Services, builds | M2 Ultra Mac |
 | flamingo | Daily driver, edge | Mac mini, ~/dev is here |
 

.cursorrules

@@ -39,9 +39,6 @@ These rules apply to every task across every project, regardless of harness.
 4. **Goal-driven execution.** Define clear success criteria up front for every task.
    Loop — implement, verify, refine — until those criteria are met. Don't claim
    completion without evidence (tests pass, command output, observed behavior).
-5. **Branch-per-task for multi-agent repos.** When another agent may be active on
-   the same repo, create a branch (`agent/<description>`), commit there, and open a
-   PR. Do not merge without explicit instruction from Mathias.
 
 ## Default stack
 
@@ -52,7 +49,7 @@ These rules apply to every task across every project, regardless of harness.
 | Build | Task (taskfile.dev) | Make | — |
 | Containers | Docker Compose (dev), k3s (prod) | — | — |
 | DB | PostgreSQL + sqlc | SQLite | — |
-| Search | Qdrant (vector), BM25 | — | — |
+| Search | pgvector (vector), BM25 | Qdrant (when >1M vectors or hybrid retrieval) | — |
 | Logging | slog (structured) | — | — |
 | Testing | Table-driven, testify | — | — |
 
@@ -74,7 +71,7 @@ Three machines on Tailscale:
 
 | Machine | Role | Key specs |
 |---------|------|-----------|
-| koala | GPU inference, heavy compute | RTX 5070, runs llama-swap, Qdrant |
+| koala | GPU inference, heavy compute | RTX 5070, runs k3s + llama-swap + shared postgres18/pgvector |
 | iguana | Services, builds | M2 Ultra Mac |
 | flamingo | Daily driver, edge | Mac mini, ~/dev is here |
 

AGENTS.md

@@ -36,9 +36,6 @@ These rules apply to every task across every project, regardless of harness.
 4. **Goal-driven execution.** Define clear success criteria up front for every task.
    Loop — implement, verify, refine — until those criteria are met. Don't claim
    completion without evidence (tests pass, command output, observed behavior).
-5. **Branch-per-task for multi-agent repos.** When another agent may be active on
-   the same repo, create a branch (`agent/<description>`), commit there, and open a
-   PR. Do not merge without explicit instruction from Mathias.
 
 ## Default stack
 
@@ -49,7 +46,7 @@ These rules apply to every task across every project, regardless of harness.
 | Build | Task (taskfile.dev) | Make | — |
 | Containers | Docker Compose (dev), k3s (prod) | — | — |
 | DB | PostgreSQL + sqlc | SQLite | — |
-| Search | Qdrant (vector), BM25 | — | — |
+| Search | pgvector (vector), BM25 | Qdrant (when >1M vectors or hybrid retrieval) | — |
 | Logging | slog (structured) | — | — |
 | Testing | Table-driven, testify | — | — |
 
@@ -71,7 +68,7 @@ Three machines on Tailscale:
 
 | Machine | Role | Key specs |
 |---------|------|-----------|
-| koala | GPU inference, heavy compute | RTX 5070, runs llama-swap, Qdrant |
+| koala | GPU inference, heavy compute | RTX 5070, runs k3s + llama-swap + shared postgres18/pgvector |
 | iguana | Services, builds | M2 Ultra Mac |
 | flamingo | Daily driver, edge | Mac mini, ~/dev is here |
 

cmd/gitea-mcp/main.go

@@ -40,6 +40,7 @@ func main() {
 	reg.Register(tools.NewRepoGet(giteaClient, ownerAllow))
 	reg.Register(tools.NewRepoSearch(giteaClient, ownerAllow))
 	reg.Register(tools.NewRepoStatus(giteaClient, ownerAllow))
+	reg.Register(tools.NewRepoUpdate(giteaClient, ownerAllow))
 	reg.Register(tools.NewFileRead(giteaClient, ownerAllow))
 	reg.Register(tools.NewFileWriteBranch(giteaClient, ownerAllow))
 	reg.Register(tools.NewFileDelete(giteaClient, ownerAllow))

internal/gitea/repos.go

@@ -86,3 +86,34 @@ func (c *Client) GetRepo(ctx context.Context, owner, name string) (*Repo, error)
 	}
 	return &r, nil
 }
+
+// EditRepoArgs carries optional fields for PATCH /api/v1/repos/{owner}/{name}.
+// Pointer fields let the caller omit unset values from the wire payload, so the
+// server only patches what was explicitly requested.
+type EditRepoArgs struct {
+	Archived    *bool   `json:"archived,omitempty"`
+	Description *string `json:"description,omitempty"`
+	Private     *bool   `json:"private,omitempty"`
+	Website     *string `json:"website,omitempty"`
+	Template    *bool   `json:"template,omitempty"`
+}
+
+func (c *Client) EditRepo(ctx context.Context, owner, name string, args EditRepoArgs) (*Repo, error) {
+	body, err := json.Marshal(args)
+	if err != nil {
+		return nil, fmt.Errorf("marshal edit args: %w", err)
+	}
+	path := fmt.Sprintf("/api/v1/repos/%s/%s", owner, name)
+	resp, status, err := c.PatchJSON(ctx, path, body)
+	if err != nil {
+		return nil, err
+	}
+	if err := MapStatus(status, resp); err != nil {
+		return nil, err
+	}
+	var r Repo
+	if err := json.Unmarshal(resp, &r); err != nil {
+		return nil, err
+	}
+	return &r, nil
+}

internal/tools/create_project_from_template.go

@@ -45,14 +45,15 @@ 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 the template, applying placeholder substitutions to known files.",
+		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).",
 		InputSchema: json.RawMessage(`{
 			"type":"object",
 			"properties":{
 				"owner":{"type":"string"},
 				"name":{"type":"string","pattern":"^[a-z][a-z0-9-]{1,38}[a-z0-9]$"},
 				"description":{"type":"string"},
-				"private":{"type":"boolean"}
+				"private":{"type":"boolean"},
+				"template_name":{"type":"string","description":"Template repo name to generate from. Defaults to the server-configured template."}
 			},
 			"required":["owner","name"]
 		}`),
@@ -60,10 +61,11 @@ func (t *CreateProjectFromTemplate) Descriptor() registry.ToolDescriptor {
 }
 
 type createProjectArgs struct {
-	Owner       string `json:"owner"`
-	Name        string `json:"name"`
-	Description string `json:"description"`
-	Private     bool   `json:"private"`
+	Owner        string `json:"owner"`
+	Name         string `json:"name"`
+	Description  string `json:"description"`
+	Private      bool   `json:"private"`
+	TemplateName string `json:"template_name"`
 }
 
 type createProjectResult struct {
@@ -91,13 +93,20 @@ func (t *CreateProjectFromTemplate) Call(ctx context.Context, raw json.RawMessag
 		return nil, fmt.Errorf("name %q does not match pattern %s: %w", args.Name, nameRe.String(), gitea.ErrValidation)
 	}
 
+	// Resolve template: per-call override takes precedence over the
+	// server-configured default. Owner stays server-configured.
+	tmplName := args.TemplateName
+	if tmplName == "" {
+		tmplName = t.templateName
+	}
+
 	// Verify template exists and is marked as a template repo.
-	tmpl, err := t.c.GetRepo(ctx, t.templateOwner, t.templateName)
+	tmpl, err := t.c.GetRepo(ctx, t.templateOwner, tmplName)
 	if err != nil {
 		return nil, fmt.Errorf("template lookup: %w", err)
 	}
 	if !tmpl.Template {
-		return nil, fmt.Errorf("repo %s/%s is not marked as template: %w", t.templateOwner, t.templateName, gitea.ErrValidation)
+		return nil, fmt.Errorf("repo %s/%s is not marked as template: %w", t.templateOwner, tmplName, gitea.ErrValidation)
 	}
 
 	// Verify destination doesn't already exist.
@@ -108,7 +117,7 @@ func (t *CreateProjectFromTemplate) Call(ctx context.Context, raw json.RawMessag
 	}
 
 	// Generate repo from template.
-	newRepo, err := t.c.GenerateFromTemplate(ctx, t.templateOwner, t.templateName, gitea.GenerateFromTemplateArgs{
+	newRepo, err := t.c.GenerateFromTemplate(ctx, t.templateOwner, tmplName, gitea.GenerateFromTemplateArgs{
 		Owner:       args.Owner,
 		Name:        args.Name,
 		Description: args.Description,

internal/tools/create_project_from_template_test.go

@@ -122,6 +122,62 @@ func TestCreateProjectHappyPath(t *testing.T) {
 	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
+
+	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)
+		}
+	}))
+	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")
+}
+
 // TestCreateProjectNameRegexFailure: invalid name returns ErrValidation without hitting network.
 func TestCreateProjectNameRegexFailure(t *testing.T) {
 	tool := tools.NewCreateProjectFromTemplate(

internal/tools/pr_files_diff.go

@@ -143,7 +143,13 @@ func splitUnifiedDiff(d []byte) map[string][]byte {
 
 	flush := func() {
 		if currentFile != "" {
-			m[currentFile] = current.Bytes()
+			// Copy: bytes.Buffer.Bytes() returns the internal slice,
+			// which Reset() then reuses. Without the copy, every map
+			// entry ends up aliased to the last file's data.
+			b := current.Bytes()
+			cp := make([]byte, len(b))
+			copy(cp, b)
+			m[currentFile] = cp
 			current.Reset()
 		}
 	}

internal/tools/pr_files_diff_test.go

@@ -97,6 +97,47 @@ func TestPRFilesDiffSmall(t *testing.T) {
 	assert.ElementsMatch(t, fileNames, paths)
 }
 
+// Regression for issue #25: every file's diff entry must contain its OWN diff,
+// not a shared buffer pointing at the last file. Prior bug: splitUnifiedDiff
+// flushed bytes.Buffer.Bytes() into the map without copying, so every entry
+// aliased the buffer's backing array and showed the last file's content.
+func TestPRFilesDiffPerFileIsolation(t *testing.T) {
+	fileNames := []string{"alpha.go", "beta.go", "gamma.go", "delta.go"}
+	rawDiff := buildDiff(fileNames, 5)
+	filesJSON := buildFilesJSON(fileNames, 5)
+
+	srv := newPRFilesDiffServer(t, filesJSON, rawDiff)
+	defer srv.Close()
+
+	tool := tools.NewPRFilesDiff(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"o"}))
+	result, err := tool.Call(context.Background(), json.RawMessage(`{"owner":"o","name":"r","number":1}`))
+	require.NoError(t, err)
+
+	var out struct {
+		Files []struct {
+			Path string `json:"path"`
+			Diff string `json:"diff"`
+		} `json:"files"`
+	}
+	require.NoError(t, json.Unmarshal(result, &out))
+	require.Len(t, out.Files, len(fileNames))
+
+	for _, f := range out.Files {
+		expected := fmt.Sprintf("diff --git a/%s b/%s", f.Path, f.Path)
+		assert.Contains(t, f.Diff, expected,
+			"file %s diff must contain its own header, got: %.80q", f.Path, f.Diff)
+		// No other file's header should leak in.
+		for _, other := range fileNames {
+			if other == f.Path {
+				continue
+			}
+			otherHeader := fmt.Sprintf("diff --git a/%s b/%s", other, other)
+			assert.NotContains(t, f.Diff, otherHeader,
+				"file %s diff must NOT contain %s's header", f.Path, other)
+		}
+	}
+}
+
 func TestPRFilesDiffPerFileTruncated(t *testing.T) {
 	// One file with a 30KB diff (each "+abcdefghij\n" = 12 bytes; 30KB / 12 ≈ 2560 lines).
 	fileNames := []string{"bigfile.go"}

internal/tools/repo_update.go

@@ -0,0 +1,81 @@
+package tools
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/registry"
+)
+
+type RepoUpdate struct {
+	c *gitea.Client
+	a *allowlist.Allowlist
+}
+
+func NewRepoUpdate(c *gitea.Client, a *allowlist.Allowlist) *RepoUpdate {
+	return &RepoUpdate{c: c, a: a}
+}
+
+func (t *RepoUpdate) Descriptor() registry.ToolDescriptor {
+	return registry.ToolDescriptor{
+		Name: "repo_update",
+		Description: "Update repository metadata via PATCH (archived, description, private, website, template). " +
+			"Only fields explicitly set in the call are patched. " +
+			"WARNING: private=false exposes the repo publicly — verify intent before calling.",
+		InputSchema: json.RawMessage(`{
+			"type":"object",
+			"properties":{
+				"owner":{"type":"string"},
+				"name":{"type":"string"},
+				"archived":{"type":"boolean","description":"Mark repo as archived (read-only). Reversible."},
+				"description":{"type":"string"},
+				"private":{"type":"boolean","description":"Toggle visibility. false makes the repo public."},
+				"website":{"type":"string","description":"Homepage URL"},
+				"template":{"type":"boolean","description":"Toggle template-repo flag"}
+			},
+			"required":["owner","name"]
+		}`),
+	}
+}
+
+type repoUpdateArgs struct {
+	Owner       string  `json:"owner"`
+	Name        string  `json:"name"`
+	Archived    *bool   `json:"archived,omitempty"`
+	Description *string `json:"description,omitempty"`
+	Private     *bool   `json:"private,omitempty"`
+	Website     *string `json:"website,omitempty"`
+	Template    *bool   `json:"template,omitempty"`
+}
+
+func (t *RepoUpdate) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
+	var args repoUpdateArgs
+	if err := parseArgs(raw, &args); err != nil {
+		return nil, err
+	}
+	if err := t.a.Check(args.Owner); err != nil {
+		return nil, err
+	}
+	if args.Name == "" {
+		return nil, fmt.Errorf("name required: %w", gitea.ErrValidation)
+	}
+	if args.Archived == nil && args.Description == nil && args.Private == nil &&
+		args.Website == nil && args.Template == nil {
+		return nil, fmt.Errorf("at least one updatable field must be set: %w", gitea.ErrValidation)
+	}
+
+	updated, err := t.c.EditRepo(ctx, args.Owner, args.Name, gitea.EditRepoArgs{
+		Archived:    args.Archived,
+		Description: args.Description,
+		Private:     args.Private,
+		Website:     args.Website,
+		Template:    args.Template,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("edit repo: %w", err)
+	}
+	return textOK(updated)
+}

internal/tools/repo_update_test.go

@@ -0,0 +1,139 @@
+package tools_test
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/tools"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func newRepoUpdateTool(srvURL string) *tools.RepoUpdate {
+	return tools.NewRepoUpdate(gitea.NewClient(srvURL, "tok"), allowlist.New([]string{"mathias"}))
+}
+
+// TestRepoUpdateArchive: happy path — set archived=true.
+func TestRepoUpdateArchive(t *testing.T) {
+	var patchedBody []byte
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		require.Equal(t, http.MethodPatch, r.Method)
+		require.Equal(t, "/api/v1/repos/mathias/old-svc", r.URL.Path)
+		patchedBody, _ = io.ReadAll(r.Body)
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"name":"old-svc","full_name":"mathias/old-svc","default_branch":"main","template":false,"private":false}`))
+	}))
+	defer srv.Close()
+
+	tool := newRepoUpdateTool(srv.URL)
+	result, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"mathias","name":"old-svc","archived":true}`,
+	))
+	require.NoError(t, err)
+
+	// Wire payload only contains the field that was actually set.
+	var sent map[string]any
+	require.NoError(t, json.Unmarshal(patchedBody, &sent))
+	assert.Equal(t, true, sent["archived"])
+	assert.NotContains(t, sent, "description")
+	assert.NotContains(t, sent, "private")
+	assert.NotContains(t, sent, "website")
+	assert.NotContains(t, sent, "template")
+
+	var repo gitea.Repo
+	require.NoError(t, json.Unmarshal(result, &repo))
+	assert.Equal(t, "mathias/old-svc", repo.FullName)
+}
+
+// TestRepoUpdateMultipleFields: set description + template flag in one call.
+func TestRepoUpdateMultipleFields(t *testing.T) {
+	var patchedBody []byte
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		patchedBody, _ = io.ReadAll(r.Body)
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"name":"template-go-agent","full_name":"mathias/template-go-agent","description":"Go agent template","template":true}`))
+	}))
+	defer srv.Close()
+
+	tool := newRepoUpdateTool(srv.URL)
+	_, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"mathias","name":"template-go-agent","description":"Go agent template","template":true}`,
+	))
+	require.NoError(t, err)
+
+	var sent map[string]any
+	require.NoError(t, json.Unmarshal(patchedBody, &sent))
+	assert.Equal(t, "Go agent template", sent["description"])
+	assert.Equal(t, true, sent["template"])
+	assert.NotContains(t, sent, "archived")
+	assert.NotContains(t, sent, "private")
+}
+
+// TestRepoUpdateNoFieldsRejected: zero updatable fields → validation error before network.
+func TestRepoUpdateNoFieldsRejected(t *testing.T) {
+	tool := tools.NewRepoUpdate(
+		gitea.NewClient("http://unused", ""),
+		allowlist.New([]string{"mathias"}),
+	)
+	_, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"mathias","name":"some-repo"}`,
+	))
+	require.Error(t, err)
+	assert.ErrorIs(t, err, gitea.ErrValidation)
+}
+
+// TestRepoUpdateMakePublic: explicit private=false is allowed; wire payload carries the false.
+// (The destructive nature is warned about in the tool description, not blocked by the tool.)
+func TestRepoUpdateMakePublic(t *testing.T) {
+	var patchedBody []byte
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		patchedBody, _ = io.ReadAll(r.Body)
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"name":"open-repo","full_name":"mathias/open-repo","private":false}`))
+	}))
+	defer srv.Close()
+
+	tool := newRepoUpdateTool(srv.URL)
+	_, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"mathias","name":"open-repo","private":false}`,
+	))
+	require.NoError(t, err)
+
+	var sent map[string]any
+	require.NoError(t, json.Unmarshal(patchedBody, &sent))
+	assert.Equal(t, false, sent["private"])
+}
+
+// TestRepoUpdateAllowlistRejects: owner outside allowlist denied without network call.
+func TestRepoUpdateAllowlistRejects(t *testing.T) {
+	tool := tools.NewRepoUpdate(
+		gitea.NewClient("http://unused", ""),
+		allowlist.New([]string{"mathias"}),
+	)
+	_, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"evil","name":"some-repo","archived":true}`,
+	))
+	require.Error(t, err)
+}
+
+// TestRepoUpdateUpstreamError: server 500 propagates as ErrUpstream.
+func TestRepoUpdateUpstreamError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+		_, _ = w.Write([]byte(`{"message":"internal"}`))
+	}))
+	defer srv.Close()
+
+	tool := newRepoUpdateTool(srv.URL)
+	_, err := tool.Call(context.Background(), json.RawMessage(
+		`{"owner":"mathias","name":"some-repo","archived":true}`,
+	))
+	require.Error(t, err)
+	assert.ErrorIs(t, err, gitea.ErrUpstream)
+}