feat: merge append_content on branch file in gitlab.commit_files

CHANGELOG.md

@@ -9,6 +9,11 @@ Tag naming: `0.y.z` (no `v` prefix). Align `cmd/version.go` and `config/agent.ex
 
 ## [Unreleased]
 
+### Changed
+
+- `gitlab.create_branch`, `gitlab.commit_files`, and `gitlab.create_mr` honor `project_path` in the skill payload (fallback to agent config when omitted).
+- `gitlab.commit_files`: when an action includes `append_content`, the agent loads the file at `file_path` on the target branch, appends the block, and commits the merged body (avoids replacing the file with RAG-assembled snapshots).
+
 ## [0.1.0] - 2026-05-26
 
 ### Added

internal/agent/agent.go

@@ -118,12 +118,13 @@ func (a *Agent) execute(skill string, payload map[string]interface{}, _ map[stri
 
 	switch skill {
 	case "gitlab.create_branch":
+		projectPath := stringFromPayload(payload, "project_path", a.cfg.GitLab.ProjectPath)
 		branch, _ := payload["branch"].(string)
 		ref, _ := payload["ref"].(string)
 		if ref == "" {
 			ref = a.cfg.GitLab.TargetBranch
 		}
-		if err := a.gitlab.CreateBranch(a.cfg.GitLab.ProjectPath, branch, ref); err != nil {
+		if err := a.gitlab.CreateBranch(projectPath, branch, ref); err != nil {
 			return nil, err
 		}
 		return skillresult.Success(map[string]interface{}{"branch": branch}), nil
@@ -138,7 +139,8 @@ func (a *Agent) execute(skill string, payload map[string]interface{}, _ map[stri
 				normalized = append(normalized, m)
 			}
 		}
-		if err := a.gitlab.CommitFiles(a.cfg.GitLab.ProjectPath, branch, message, normalized); err != nil {
+		projectPath := stringFromPayload(payload, "project_path", a.cfg.GitLab.ProjectPath)
+		if err := a.gitlab.CommitFiles(projectPath, branch, message, normalized); err != nil {
 			return nil, err
 		}
 		return skillresult.Success(map[string]interface{}{}), nil
@@ -151,7 +153,8 @@ func (a *Agent) execute(skill string, payload map[string]interface{}, _ map[stri
 		}
 		title, _ := payload["title"].(string)
 		description, _ := payload["description"].(string)
-		url, err := a.gitlab.CreateMergeRequest(a.cfg.GitLab.ProjectPath, source, target, title, description)
+		projectPath := stringFromPayload(payload, "project_path", a.cfg.GitLab.ProjectPath)
+		url, err := a.gitlab.CreateMergeRequest(projectPath, source, target, title, description)
 		if err != nil {
 			return nil, err
 		}

internal/gitlab/client.go

@@ -2,6 +2,7 @@ package gitlab
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -26,7 +27,14 @@ type APIError struct {
 }
 
 func (e *APIError) Error() string {
-	return fmt.Sprintf("gitlab API error status=%d", e.StatusCode)
+	body := strings.TrimSpace(e.Body)
+	if body == "" {
+		return fmt.Sprintf("gitlab API error status=%d", e.StatusCode)
+	}
+	if len(body) > 500 {
+		body = body[:500] + "..."
+	}
+	return fmt.Sprintf("gitlab API error status=%d: %s", e.StatusCode, body)
 }
 
 func New(baseURL, token, apiVersion string) *Client {
@@ -72,15 +80,75 @@ func (c *Client) CreateBranch(projectPath, branch, ref string) error {
 	return c.post(fmt.Sprintf("/projects/%s/repository/branches", c.projectID(projectPath)), body, nil)
 }
 
+// GetRepositoryFile returns the decoded text of a file at ref (branch, tag, or commit SHA).
+func (c *Client) GetRepositoryFile(projectPath, filePath, ref string) (string, error) {
+	resp := map[string]interface{}{}
+	path := fmt.Sprintf(
+		"/projects/%s/repository/files/%s?ref=%s",
+		c.projectID(projectPath),
+		url.PathEscape(strings.TrimPrefix(filePath, "/")),
+		url.QueryEscape(ref),
+	)
+	if err := c.get(path, &resp); err != nil {
+		return "", err
+	}
+	encoding, _ := resp["encoding"].(string)
+	content, _ := resp["content"].(string)
+	if content == "" {
+		return "", fmt.Errorf("repository file %q at ref %q is empty", filePath, ref)
+	}
+	if encoding == "base64" {
+		raw, err := base64.StdEncoding.DecodeString(content)
+		if err != nil {
+			return "", fmt.Errorf("decode repository file %q: %w", filePath, err)
+		}
+		return string(raw), nil
+	}
+	return content, nil
+}
+
 func (c *Client) CommitFiles(projectPath, branch, message string, actions []map[string]interface{}) error {
+	resolved := make([]map[string]interface{}, 0, len(actions))
+	for _, action := range actions {
+		merged, err := c.resolveCommitAction(projectPath, branch, action)
+		if err != nil {
+			return err
+		}
+		resolved = append(resolved, merged)
+	}
 	body := map[string]interface{}{
 		"branch":         branch,
 		"commit_message": message,
-		"actions":        actions,
+		"actions":        resolved,
 	}
 	return c.post(fmt.Sprintf("/projects/%s/repository/commits", c.projectID(projectPath)), body, nil)
 }
 
+func (c *Client) resolveCommitAction(projectPath, branch string, action map[string]interface{}) (map[string]interface{}, error) {
+	out := make(map[string]interface{}, len(action))
+	for k, v := range action {
+		out[k] = v
+	}
+	appendText, _ := out["append_content"].(string)
+	appendText = strings.TrimSpace(appendText)
+	if appendText == "" {
+		delete(out, "append_content")
+		return out, nil
+	}
+	act, _ := out["action"].(string)
+	filePath, _ := out["file_path"].(string)
+	if act != "update" || strings.TrimSpace(filePath) == "" {
+		return nil, fmt.Errorf("append_content requires action update and file_path")
+	}
+	existing, err := c.GetRepositoryFile(projectPath, filePath, branch)
+	if err != nil {
+		return nil, err
+	}
+	out["content"] = strings.TrimRight(existing, "\n") + "\n\n" + appendText + "\n"
+	delete(out, "append_content")
+	return out, nil
+}
+
 func (c *Client) CreateMergeRequest(projectPath, source, target, title, description string) (string, error) {
 	resp := map[string]interface{}{}
 	body := map[string]interface{}{