chore: bump version to 0.4.1

fix: persist toolCalls to database for reload persistence
Tool usage was not showing after page reload because the toolCalls field was not being included when saving assistant messages to the database. Now toolCalls are properly persisted and restored.
2026-01-02 20:36:03 +01:00 · 2026-01-02 20:34:53 +01:00 · 2026-01-02 20:15:40 +01:00 · 2026-01-02 19:46:29 +01:00 · 2026-01-02 19:42:47 +01:00
18 changed files with 1495 additions and 27 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -0,0 +1,27 @@
+name: Create Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          generate_release_notes: true
+          body: |
+            See the [full release notes on Gitea](https://somegit.dev/vikingowl/vessel/releases) for detailed information.
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
--- a/.gitignore
+++ b/.gitignore
@@ -33,3 +33,6 @@ backend/server
 # Docker
 *.pid
 docker-compose.override.yml
+
+# Claude Code project instructions (local only)
+CLAUDE.md
--- a/backend/Dockerfile
+++ b/backend/Dockerfile
@@ -18,8 +18,8 @@ RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o server ./cmd/serv
 # Final stage
 FROM alpine:latest

-# curl for web fetching, ca-certificates for HTTPS
-RUN apk --no-cache add ca-certificates curl
+# curl for web fetching, ca-certificates for HTTPS, python3 for tool execution
+RUN apk --no-cache add ca-certificates curl python3

 WORKDIR /app

--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -18,7 +18,7 @@ import (
 )

 // Version is set at build time via -ldflags, or defaults to dev
-var Version = "0.3.0"
+var Version = "0.4.1"

 func getEnvOrDefault(key, defaultValue string) string {
 	if value := os.Getenv(key); value != "" {
--- a/backend/internal/api/routes.go
+++ b/backend/internal/api/routes.go
@@ -66,6 +66,9 @@ func SetupRoutes(r *gin.Engine, db *sql.DB, ollamaURL string, appVersion string)
 		// IP-based geolocation (fallback when browser geolocation fails)
 		v1.GET("/location", IPGeolocationHandler())

+		// Tool execution (for Python tools)
+		v1.POST("/tools/execute", ExecuteToolHandler())
+
 		// Model registry routes (cached models from ollama.com)
 		models := v1.Group("/models")
 		{
--- a/backend/internal/api/tools.go
+++ b/backend/internal/api/tools.go
@@ -0,0 +1,174 @@
+package api
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"os"
+	"os/exec"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+// ExecuteToolRequest represents a tool execution request
+type ExecuteToolRequest struct {
+	Language string                 `json:"language" binding:"required,oneof=python javascript"`
+	Code     string                 `json:"code" binding:"required"`
+	Args     map[string]interface{} `json:"args"`
+	Timeout  int                    `json:"timeout"` // seconds, default 30
+}
+
+// ExecuteToolResponse represents the tool execution response
+type ExecuteToolResponse struct {
+	Success bool        `json:"success"`
+	Result  interface{} `json:"result,omitempty"`
+	Error   string      `json:"error,omitempty"`
+	Stdout  string      `json:"stdout,omitempty"`
+	Stderr  string      `json:"stderr,omitempty"`
+}
+
+// MaxOutputSize is the maximum size of tool output (100KB)
+const MaxOutputSize = 100 * 1024
+
+// ExecuteToolHandler handles tool execution requests
+func ExecuteToolHandler() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		var req ExecuteToolRequest
+		if err := c.ShouldBindJSON(&req); err != nil {
+			c.JSON(http.StatusBadRequest, ExecuteToolResponse{
+				Success: false,
+				Error:   "Invalid request: " + err.Error(),
+			})
+			return
+		}
+
+		// Default timeout
+		timeout := req.Timeout
+		if timeout <= 0 || timeout > 60 {
+			timeout = 30
+		}
+
+		var resp ExecuteToolResponse
+
+		switch req.Language {
+		case "python":
+			resp = executePython(req.Code, req.Args, timeout)
+		case "javascript":
+			// JavaScript execution not supported on backend (runs in browser)
+			resp = ExecuteToolResponse{
+				Success: false,
+				Error:   "JavaScript tools should be executed in the browser",
+			}
+		default:
+			resp = ExecuteToolResponse{
+				Success: false,
+				Error:   "Unsupported language: " + req.Language,
+			}
+		}
+
+		c.JSON(http.StatusOK, resp)
+	}
+}
+
+// executePython executes Python code with the given arguments
+func executePython(code string, args map[string]interface{}, timeout int) ExecuteToolResponse {
+	// Create a wrapper script that reads args from stdin
+	wrapperScript := `
+import json
+import sys
+
+# Read args from stdin
+args = json.loads(sys.stdin.read())
+
+# Execute user code
+` + code
+
+	// Create temp file for the script
+	tmpFile, err := os.CreateTemp("", "tool-*.py")
+	if err != nil {
+		return ExecuteToolResponse{
+			Success: false,
+			Error:   "Failed to create temp file: " + err.Error(),
+		}
+	}
+	defer os.Remove(tmpFile.Name())
+
+	if _, err := tmpFile.WriteString(wrapperScript); err != nil {
+		return ExecuteToolResponse{
+			Success: false,
+			Error:   "Failed to write script: " + err.Error(),
+		}
+	}
+	tmpFile.Close()
+
+	// Marshal args to JSON for stdin
+	argsJSON, err := json.Marshal(args)
+	if err != nil {
+		return ExecuteToolResponse{
+			Success: false,
+			Error:   "Failed to serialize args: " + err.Error(),
+		}
+	}
+
+	// Create context with timeout
+	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
+	defer cancel()
+
+	// Execute Python (using exec.Command, not shell)
+	cmd := exec.CommandContext(ctx, "python3", tmpFile.Name())
+	cmd.Stdin = bytes.NewReader(argsJSON)
+
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	err = cmd.Run()
+
+	// Check for timeout
+	if ctx.Err() == context.DeadlineExceeded {
+		return ExecuteToolResponse{
+			Success: false,
+			Error:   "Execution timed out after " + string(rune(timeout)) + " seconds",
+			Stderr:  truncateOutput(stderr.String()),
+		}
+	}
+
+	// Truncate output if needed
+	stdoutStr := truncateOutput(stdout.String())
+	stderrStr := truncateOutput(stderr.String())
+
+	if err != nil {
+		return ExecuteToolResponse{
+			Success: false,
+			Error:   "Execution failed: " + err.Error(),
+			Stdout:  stdoutStr,
+			Stderr:  stderrStr,
+		}
+	}
+
+	// Try to parse stdout as JSON
+	var result interface{}
+	if stdoutStr != "" {
+		if err := json.Unmarshal([]byte(stdoutStr), &result); err != nil {
+			// If not valid JSON, return as string
+			result = stdoutStr
+		}
+	}
+
+	return ExecuteToolResponse{
+		Success: true,
+		Result:  result,
+		Stdout:  stdoutStr,
+		Stderr:  stderrStr,
+	}
+}
+
+// truncateOutput truncates output to MaxOutputSize
+func truncateOutput(s string) string {
+	if len(s) > MaxOutputSize {
+		return s[:MaxOutputSize] + "\n... (output truncated)"
+	}
+	return s
+}
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -1,17 +1,22 @@
 {
  "name": "vessel",
-  "version": "0.1.0",
+  "version": "0.3.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "vessel",
-      "version": "0.1.0",
+      "version": "0.3.0",
      "dependencies": {
+        "@codemirror/lang-javascript": "^6.2.3",
+        "@codemirror/lang-json": "^6.0.1",
+        "@codemirror/lang-python": "^6.1.7",
+        "@codemirror/theme-one-dark": "^6.1.2",
        "@skeletonlabs/skeleton": "^2.10.0",
        "@skeletonlabs/tw-plugin": "^0.4.0",
        "@sveltejs/adapter-node": "^5.4.0",
        "@types/dompurify": "^3.0.5",
+        "codemirror": "^6.0.1",
        "dexie": "^4.0.10",
        "dompurify": "^3.2.0",
        "marked": "^15.0.0",
@@ -110,6 +115,137 @@
        "node": ">=6.9.0"
      }
    },
+    "node_modules/@codemirror/autocomplete": {
+      "version": "6.20.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/autocomplete/-/autocomplete-6.20.0.tgz",
+      "integrity": "sha512-bOwvTOIJcG5FVo5gUUupiwYh8MioPLQ4UcqbcRf7UQ98X90tCa9E1kZ3Z7tqwpZxYyOvh1YTYbmZE9RTfTp5hg==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/commands": {
+      "version": "6.10.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/commands/-/commands-6.10.1.tgz",
+      "integrity": "sha512-uWDWFypNdQmz2y1LaNJzK7fL7TYKLeUAU0npEC685OKTF3KcQ2Vu3klIM78D7I6wGhktme0lh3CuQLv0ZCrD9Q==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.4.0",
+        "@codemirror/view": "^6.27.0",
+        "@lezer/common": "^1.1.0"
+      }
+    },
+    "node_modules/@codemirror/lang-javascript": {
+      "version": "6.2.4",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-javascript/-/lang-javascript-6.2.4.tgz",
+      "integrity": "sha512-0WVmhp1QOqZ4Rt6GlVGwKJN3KW7Xh4H2q8ZZNGZaP6lRdxXJzmjm4FqvmOojVj6khWJHIb9sp7U/72W7xQgqAA==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.6.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/javascript": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-json": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-json/-/lang-json-6.0.2.tgz",
+      "integrity": "sha512-x2OtO+AvwEHrEwR0FyyPtfDUiloG3rnVTSZV1W8UteaLL8/MajQd8DpvUb2YVzC+/T18aSDv0H9mu+xw0EStoQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@lezer/json": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-python": {
+      "version": "6.2.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-python/-/lang-python-6.2.1.tgz",
+      "integrity": "sha512-IRjC8RUBhn9mGR9ywecNhB51yePWCGgvHfY1lWN/Mrp3cKuHr0isDKia+9HnvhiWNnMpbGhWrkhuWOc09exRyw==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.3.2",
+        "@codemirror/language": "^6.8.0",
+        "@codemirror/state": "^6.0.0",
+        "@lezer/common": "^1.2.1",
+        "@lezer/python": "^1.1.4"
+      }
+    },
+    "node_modules/@codemirror/language": {
+      "version": "6.12.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/language/-/language-6.12.1.tgz",
+      "integrity": "sha512-Fa6xkSiuGKc8XC8Cn96T+TQHYj4ZZ7RdFmXA3i9xe/3hLHfwPZdM+dqfX0Cp0zQklBKhVD8Yzc8LS45rkqcwpQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.23.0",
+        "@lezer/common": "^1.5.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0",
+        "style-mod": "^4.0.0"
+      }
+    },
+    "node_modules/@codemirror/lint": {
+      "version": "6.9.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lint/-/lint-6.9.2.tgz",
+      "integrity": "sha512-sv3DylBiIyi+xKwRCJAAsBZZZWo82shJ/RTMymLabAdtbkV5cSKwWDeCgtUq3v8flTaXS2y1kKkICuRYtUswyQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.35.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/search": {
+      "version": "6.5.11",
+      "resolved": "https://registry.npmjs.org/@codemirror/search/-/search-6.5.11.tgz",
+      "integrity": "sha512-KmWepDE6jUdL6n8cAAqIpRmLPBZ5ZKnicE8oGU/s3QrAVID+0VhLFrzUucVKHG5035/BSykhExDL/Xm7dHthiA==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/state": {
+      "version": "6.5.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/state/-/state-6.5.3.tgz",
+      "integrity": "sha512-MerMzJzlXogk2fxWFU1nKp36bY5orBG59HnPiz0G9nLRebWa0zXuv2siH6PLIHBvv5TH8CkQRqjBs0MlxCZu+A==",
+      "license": "MIT",
+      "dependencies": {
+        "@marijn/find-cluster-break": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/theme-one-dark": {
+      "version": "6.1.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/theme-one-dark/-/theme-one-dark-6.1.3.tgz",
+      "integrity": "sha512-NzBdIvEJmx6fjeremiGp3t/okrLPYT0d9orIc7AFun8oZcRk58aejkqhv6spnz4MLAevrKNPMQYXEWMg4s+sKA==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/highlight": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/view": {
+      "version": "6.39.8",
+      "resolved": "https://registry.npmjs.org/@codemirror/view/-/view-6.39.8.tgz",
+      "integrity": "sha512-1rASYd9Z/mE3tkbC9wInRlCNyCkSn+nLsiQKZhEDUUJiUfs/5FHDpCUDaQpoTIaNGeDc6/bhaEAyLmeEucEFPw==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.5.0",
+        "crelt": "^1.0.6",
+        "style-mod": "^4.1.0",
+        "w3c-keyname": "^2.2.4"
+      }
+    },
    "node_modules/@csstools/color-helpers": {
      "version": "5.1.0",
      "dev": true,
@@ -698,6 +834,69 @@
        "@jridgewell/sourcemap-codec": "^1.4.14"
      }
    },
+    "node_modules/@lezer/common": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/@lezer/common/-/common-1.5.0.tgz",
+      "integrity": "sha512-PNGcolp9hr4PJdXR4ix7XtixDrClScvtSCYW3rQG106oVMOOI+jFb+0+J3mbeL/53g1Zd6s0kJzaw6Ri68GmAA==",
+      "license": "MIT"
+    },
+    "node_modules/@lezer/highlight": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/@lezer/highlight/-/highlight-1.2.3.tgz",
+      "integrity": "sha512-qXdH7UqTvGfdVBINrgKhDsVTJTxactNNxLk7+UMwZhU13lMHaOBlJe9Vqp907ya56Y3+ed2tlqzys7jDkTmW0g==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/javascript": {
+      "version": "1.5.4",
+      "resolved": "https://registry.npmjs.org/@lezer/javascript/-/javascript-1.5.4.tgz",
+      "integrity": "sha512-vvYx3MhWqeZtGPwDStM2dwgljd5smolYD2lR2UyFcHfxbBQebqx8yjmFmxtJ/E6nN6u1D9srOiVWm3Rb4tmcUA==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.1.3",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/json": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@lezer/json/-/json-1.0.3.tgz",
+      "integrity": "sha512-BP9KzdF9Y35PDpv04r0VeSTKDeox5vVr3efE7eBbx3r4s3oNLfunchejZhjArmeieBH+nVOpgIiBJpEAv8ilqQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/lr": {
+      "version": "1.4.5",
+      "resolved": "https://registry.npmjs.org/@lezer/lr/-/lr-1.4.5.tgz",
+      "integrity": "sha512-/YTRKP5yPPSo1xImYQk7AZZMAgap0kegzqCSYHjAL9x1AZ0ZQW+IpcEzMKagCsbTsLnVeWkxYrCNeXG8xEPrjg==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/python": {
+      "version": "1.1.18",
+      "resolved": "https://registry.npmjs.org/@lezer/python/-/python-1.1.18.tgz",
+      "integrity": "sha512-31FiUrU7z9+d/ElGQLJFXl+dKOdx0jALlP3KEOsGTex8mvj+SoE1FgItcHWK/axkxCHGUSpqIHt6JAWfWu9Rhg==",
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@marijn/find-cluster-break": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@marijn/find-cluster-break/-/find-cluster-break-1.0.2.tgz",
+      "integrity": "sha512-l0h88YhZFyKdXIFNfSWpyjStDjGHwZ/U7iobcK1cQQD8sejsONdQtTVU+1wVN1PBw40PiiHB1vA5S7VTfQiP9g==",
+      "license": "MIT"
+    },
    "node_modules/@napi-rs/canvas": {
      "version": "0.1.88",
      "license": "MIT",
@@ -2049,6 +2248,21 @@
        "node": ">=6"
      }
    },
+    "node_modules/codemirror": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/codemirror/-/codemirror-6.0.2.tgz",
+      "integrity": "sha512-VhydHotNW5w1UGK0Qj96BwSk/Zqbp9WbnyK2W/eVMv4QyF41INRGpjUhFJY7/uDNuudSc33a/PKr4iDqRduvHw==",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/commands": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/search": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0"
+      }
+    },
    "node_modules/comma-separated-tokens": {
      "version": "2.0.3",
      "license": "MIT",
@@ -2075,6 +2289,12 @@
        "node": ">= 0.6"
      }
    },
+    "node_modules/crelt": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/crelt/-/crelt-1.0.6.tgz",
+      "integrity": "sha512-VQ2MBenTq1fWZUH9DJNGti7kKv6EeAuYr3cLwxUWhIu1baTaXh4Ib5W2CqHVqib4/MqbYGJqiL3Zb8GJZr3l4g==",
+      "license": "MIT"
+    },
    "node_modules/css-tree": {
      "version": "3.1.0",
      "dev": true,
@@ -3362,6 +3582,12 @@
        "url": "https://github.com/sponsors/wooorm"
      }
    },
+    "node_modules/style-mod": {
+      "version": "4.1.3",
+      "resolved": "https://registry.npmjs.org/style-mod/-/style-mod-4.1.3.tgz",
+      "integrity": "sha512-i/n8VsZydrugj3Iuzll8+x/00GH2vnYsk1eomD8QiRrSAeW6ItbCQDtfXCeJHd0iwiNagqjQkvpvREEPtW3IoQ==",
+      "license": "MIT"
+    },
    "node_modules/sucrase": {
      "version": "3.35.1",
      "license": "MIT",
@@ -3961,6 +4187,12 @@
        }
      }
    },
+    "node_modules/w3c-keyname": {
+      "version": "2.2.8",
+      "resolved": "https://registry.npmjs.org/w3c-keyname/-/w3c-keyname-2.2.8.tgz",
+      "integrity": "sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==",
+      "license": "MIT"
+    },
    "node_modules/w3c-xmlserializer": {
      "version": "5.0.0",
      "dev": true,
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,6 +1,6 @@
 {
  "name": "vessel",
-  "version": "0.3.0",
+  "version": "0.4.1",
  "private": true,
  "type": "module",
  "scripts": {
@@ -32,7 +32,12 @@
    "vitest": "^4.0.16"
  },
  "dependencies": {
+    "@codemirror/lang-javascript": "^6.2.3",
+    "@codemirror/lang-json": "^6.0.1",
+    "@codemirror/lang-python": "^6.1.7",
+    "@codemirror/theme-one-dark": "^6.1.2",
    "@skeletonlabs/skeleton": "^2.10.0",
+    "codemirror": "^6.0.1",
    "@skeletonlabs/tw-plugin": "^0.4.0",
    "@sveltejs/adapter-node": "^5.4.0",
    "@types/dompurify": "^3.0.5",
--- a/frontend/src/lib/components/chat/ChatWindow.svelte
+++ b/frontend/src/lib/components/chat/ChatWindow.svelte
@@ -604,12 +604,16 @@
 				// The results are stored in toolCalls and displayed by ToolCallDisplay
 			}

-			// Persist the assistant message (without flooding text content)
+			// Persist the assistant message (including toolCalls for reload persistence)
 			if (conversationId && assistantNode) {
 				const parentOfAssistant = assistantNode.parentId;
 				await addStoredMessage(
 					conversationId,
-					{ role: 'assistant', content: assistantNode.message.content },
+					{
+						role: 'assistant',
+						content: assistantNode.message.content,
+						toolCalls: assistantNode.message.toolCalls
+					},
 					parentOfAssistant,
 					assistantMessageId
 				);
--- a/frontend/src/lib/components/tools/CodeEditor.svelte
+++ b/frontend/src/lib/components/tools/CodeEditor.svelte
@@ -0,0 +1,127 @@
+<script lang="ts">
+	import { onMount, onDestroy } from 'svelte';
+	import { EditorView, basicSetup } from 'codemirror';
+	import { javascript } from '@codemirror/lang-javascript';
+	import { python } from '@codemirror/lang-python';
+	import { json } from '@codemirror/lang-json';
+	import { oneDark } from '@codemirror/theme-one-dark';
+	import { EditorState, Compartment } from '@codemirror/state';
+
+	interface Props {
+		value: string;
+		language?: 'javascript' | 'python' | 'json';
+		readonly?: boolean;
+		placeholder?: string;
+		minHeight?: string;
+		onchange?: (value: string) => void;
+	}
+
+	let {
+		value = $bindable(''),
+		language = 'javascript',
+		readonly = false,
+		placeholder = '',
+		minHeight = '200px',
+		onchange
+	}: Props = $props();
+
+	let editorContainer: HTMLDivElement;
+	let editorView: EditorView | null = null;
+	const languageCompartment = new Compartment();
+	const readonlyCompartment = new Compartment();
+
+	function getLanguageExtension(lang: string) {
+		switch (lang) {
+			case 'python':
+				return python();
+			case 'json':
+				return json();
+			case 'javascript':
+			default:
+				return javascript();
+		}
+	}
+
+	onMount(() => {
+		const updateListener = EditorView.updateListener.of((update) => {
+			if (update.docChanged) {
+				const newValue = update.state.doc.toString();
+				if (newValue !== value) {
+					value = newValue;
+					onchange?.(newValue);
+				}
+			}
+		});
+
+		const state = EditorState.create({
+			doc: value,
+			extensions: [
+				basicSetup,
+				languageCompartment.of(getLanguageExtension(language)),
+				readonlyCompartment.of(EditorState.readOnly.of(readonly)),
+				oneDark,
+				updateListener,
+				EditorView.theme({
+					'&': { minHeight },
+					'.cm-scroller': { overflow: 'auto' },
+					'.cm-content': { minHeight },
+					'&.cm-focused': { outline: 'none' }
+				}),
+				placeholder ? EditorView.contentAttributes.of({ 'aria-placeholder': placeholder }) : []
+			]
+		});
+
+		editorView = new EditorView({
+			state,
+			parent: editorContainer
+		});
+	});
+
+	onDestroy(() => {
+		editorView?.destroy();
+	});
+
+	// Update editor when value changes externally
+	$effect(() => {
+		if (editorView && editorView.state.doc.toString() !== value) {
+			editorView.dispatch({
+				changes: {
+					from: 0,
+					to: editorView.state.doc.length,
+					insert: value
+				}
+			});
+		}
+	});
+
+	// Update language when it changes
+	$effect(() => {
+		if (editorView) {
+			editorView.dispatch({
+				effects: languageCompartment.reconfigure(getLanguageExtension(language))
+			});
+		}
+	});
+
+	// Update readonly when it changes
+	$effect(() => {
+		if (editorView) {
+			editorView.dispatch({
+				effects: readonlyCompartment.reconfigure(EditorState.readOnly.of(readonly))
+			});
+		}
+	});
+</script>
+
+<div class="code-editor rounded-md overflow-hidden border border-surface-500/30" bind:this={editorContainer}></div>
+
+<style>
+	.code-editor :global(.cm-editor) {
+		font-size: 14px;
+		font-family: ui-monospace, SFMono-Regular, 'SF Mono', Menlo, Consolas, 'Liberation Mono', monospace;
+	}
+
+	.code-editor :global(.cm-gutters) {
+		border-right: 1px solid rgba(255, 255, 255, 0.1);
+	}
+</style>
--- a/frontend/src/lib/components/tools/ToolDocs.svelte
+++ b/frontend/src/lib/components/tools/ToolDocs.svelte
@@ -0,0 +1,117 @@
+<script lang="ts">
+	/**
+	 * ToolDocs - Inline documentation panel for tool creation
+	 */
+
+	interface Props {
+		language: 'javascript' | 'python';
+		isOpen?: boolean;
+		onclose?: () => void;
+	}
+
+	const { language, isOpen = false, onclose }: Props = $props();
+</script>
+
+{#if isOpen}
+	<div class="rounded-lg border border-theme-subtle bg-theme-tertiary/50 p-4">
+		<div class="flex items-center justify-between mb-3">
+			<h4 class="text-sm font-medium text-theme-primary">
+				{language === 'javascript' ? 'JavaScript' : 'Python'} Tool Guide
+			</h4>
+			{#if onclose}
+				<button
+					type="button"
+					onclick={onclose}
+					class="text-theme-muted hover:text-theme-primary"
+					aria-label="Close documentation"
+				>
+					<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+						<path fill-rule="evenodd" d="M4.293 4.293a1 1 0 011.414 0L10 8.586l4.293-4.293a1 1 0 111.414 1.414L11.414 10l4.293 4.293a1 1 0 01-1.414 1.414L10 11.414l-4.293 4.293a1 1 0 01-1.414-1.414L8.586 10 4.293 5.707a1 1 0 010-1.414z" clip-rule="evenodd" />
+					</svg>
+				</button>
+			{/if}
+		</div>
+
+		<div class="space-y-4 text-sm text-theme-secondary">
+			{#if language === 'javascript'}
+				<!-- JavaScript Documentation -->
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Arguments</h5>
+					<p>Access parameters via the <code class="bg-theme-primary/30 px-1 rounded text-xs">args</code> object:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>const name = args.name;
+const count = args.count || 10;</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Return Value</h5>
+					<p>Return any JSON-serializable value:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>return {'{'}
+  success: true,
+  data: result
+{'}'};</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Async/Await</h5>
+					<p>Full async support - use await for API calls:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>const res = await fetch(args.url);
+const data = await res.json();
+return data;</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Error Handling</h5>
+					<p>Throw errors to signal failures:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>if (!args.required_param) {'{'}
+  throw new Error('Missing required param');
+{'}'}</code></pre>
+				</div>
+			{:else}
+				<!-- Python Documentation -->
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Arguments</h5>
+					<p>Access parameters via the <code class="bg-theme-primary/30 px-1 rounded text-xs">args</code> dict:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>name = args.get('name')
+count = args.get('count', 10)</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Return Value</h5>
+					<p>Print JSON to stdout (import json first):</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>import json
+
+result = {'{'}'success': True, 'data': data{'}'}
+print(json.dumps(result))</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Available Modules</h5>
+					<p>Python standard library is available:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>import json, math, re
+import hashlib, base64
+import urllib.request
+from collections import Counter</code></pre>
+				</div>
+
+				<div>
+					<h5 class="font-medium text-theme-primary mb-1">Error Handling</h5>
+					<p>Print error JSON or raise exceptions:</p>
+					<pre class="mt-1 p-2 rounded bg-theme-primary/20 text-xs overflow-x-auto"><code>try:
+    # risky operation
+except Exception as e:
+    print(json.dumps({'{'}'error': str(e){'}'})</code></pre>
+				</div>
+			{/if}
+
+			<div class="pt-2 border-t border-theme-subtle">
+				<h5 class="font-medium text-theme-primary mb-1">Tips</h5>
+				<ul class="list-disc list-inside space-y-1 text-xs text-theme-muted">
+					<li>Tools run with a 30-second timeout</li>
+					<li>Large outputs are truncated at 100KB</li>
+					<li>Network requests are allowed</li>
+					<li>Use descriptive error messages for debugging</li>
+				</ul>
+			</div>
+		</div>
+	</div>
+{/if}
--- a/frontend/src/lib/components/tools/ToolEditor.svelte
+++ b/frontend/src/lib/components/tools/ToolEditor.svelte
@@ -5,6 +5,10 @@

 	import { toolsState } from '$lib/stores';
 	import type { CustomTool, JSONSchema, JSONSchemaProperty, ToolImplementation } from '$lib/tools';
+	import { getTemplatesByLanguage, type ToolTemplate } from '$lib/tools';
+	import CodeEditor from './CodeEditor.svelte';
+	import ToolDocs from './ToolDocs.svelte';
+	import ToolTester from './ToolTester.svelte';

 	interface Props {
 		isOpen: boolean;
@@ -15,21 +19,62 @@

 	const { isOpen, editingTool = null, onClose, onSave }: Props = $props();

+	// Default code templates
+	const defaultJsCode = `// Arguments are available as \`args\` object
+// Return the result
+return { message: "Hello from custom tool!" };`;
+
+	const defaultPythonCode = `# Arguments available as \`args\` dict
+# Print JSON result to stdout
+import json
+
+result = {"message": f"Hello, {args.get('name', 'World')}!"}
+print(json.dumps(result))`;
+
 	// Form state
 	let name = $state('');
 	let description = $state('');
 	let implementation = $state<ToolImplementation>('javascript');
-	let code = $state('// Arguments are available as `args` object\n// Return the result\nreturn { message: "Hello from custom tool!" };');
+	let code = $state(defaultJsCode);
 	let endpoint = $state('');
 	let httpMethod = $state<'GET' | 'POST'>('POST');
 	let enabled = $state(true);

+	// Track previous implementation for code switching
+	let prevImplementation = $state<ToolImplementation>('javascript');
+
 	// Parameters state (simplified - array of parameter definitions)
 	let parameters = $state<Array<{ name: string; type: string; description: string; required: boolean }>>([]);

 	// Validation
 	let errors = $state<Record<string, string>>({});

+	// UI state
+	let showDocs = $state(false);
+	let showTemplates = $state(false);
+	let showTest = $state(false);
+
+	// Get templates for current language
+	const currentTemplates = $derived(
+		implementation === 'javascript' || implementation === 'python'
+			? getTemplatesByLanguage(implementation)
+			: []
+	);
+
+	function applyTemplate(template: ToolTemplate): void {
+		name = template.name.toLowerCase().replace(/[^a-z0-9]+/g, '_');
+		description = template.description;
+		code = template.code;
+		// Convert parameters from template
+		parameters = Object.entries(template.parameters.properties ?? {}).map(([paramName, prop]) => ({
+			name: paramName,
+			type: prop.type,
+			description: prop.description ?? '',
+			required: template.parameters.required?.includes(paramName) ?? false
+		}));
+		showTemplates = false;
+	}
+
 	// Reset form when modal opens or editing tool changes
 	$effect(() => {
 		if (isOpen) {
@@ -59,13 +104,32 @@
 		name = '';
 		description = '';
 		implementation = 'javascript';
-		code = '// Arguments are available as `args` object\n// Return the result\nreturn { message: "Hello from custom tool!" };';
+		prevImplementation = 'javascript';
+		code = defaultJsCode;
 		endpoint = '';
 		httpMethod = 'POST';
 		enabled = true;
 		parameters = [];
 	}

+	// Switch to default code when implementation changes (unless editing)
+	$effect(() => {
+		if (!editingTool && implementation !== prevImplementation) {
+			// Only switch code if it's still the default for the previous type
+			const isDefaultJs = code === defaultJsCode || code.trim() === '';
+			const isDefaultPy = code === defaultPythonCode;
+
+			if (isDefaultJs || isDefaultPy || code.trim() === '') {
+				if (implementation === 'python') {
+					code = defaultPythonCode;
+				} else if (implementation === 'javascript') {
+					code = defaultJsCode;
+				}
+			}
+			prevImplementation = implementation;
+		}
+	});
+
 	function addParameter(): void {
 		parameters = [...parameters, { name: '', type: 'string', description: '', required: false }];
 	}
@@ -93,8 +157,8 @@
 			newErrors.description = 'Description is required';
 		}

-		if (implementation === 'javascript' && !code.trim()) {
-			newErrors.code = 'JavaScript code is required';
+		if ((implementation === 'javascript' || implementation === 'python') && !code.trim()) {
+			newErrors.code = `${implementation === 'javascript' ? 'JavaScript' : 'Python'} code is required`;
 		}

 		if (implementation === 'http' && !endpoint.trim()) {
@@ -144,7 +208,7 @@
 			description: description.trim(),
 			parameters: buildParameterSchema(),
 			implementation,
-			code: implementation === 'javascript' ? code : undefined,
+			code: (implementation === 'javascript' || implementation === 'python') ? code : undefined,
 			endpoint: implementation === 'http' ? endpoint : undefined,
 			httpMethod: implementation === 'http' ? httpMethod : undefined,
 			enabled,
@@ -290,7 +354,7 @@
 				<!-- Implementation Type -->
 				<div>
 					<label class="block text-sm font-medium text-theme-secondary">Implementation</label>
-					<div class="mt-2 flex gap-4">
+					<div class="mt-2 flex flex-wrap gap-4">
 						<label class="flex items-center gap-2 text-theme-secondary">
 							<input
 								type="radio"
@@ -300,6 +364,15 @@
 							/>
 							JavaScript
 						</label>
+						<label class="flex items-center gap-2 text-theme-secondary">
+							<input
+								type="radio"
+								bind:group={implementation}
+								value="python"
+								class="text-blue-500"
+							/>
+							Python
+						</label>
 						<label class="flex items-center gap-2 text-theme-secondary">
 							<input
 								type="radio"
@@ -312,22 +385,102 @@
 					</div>
 				</div>

-				<!-- JavaScript Code -->
-				{#if implementation === 'javascript'}
+				<!-- Code Editor (JavaScript or Python) -->
+				{#if implementation === 'javascript' || implementation === 'python'}
 					<div>
-						<label for="tool-code" class="block text-sm font-medium text-theme-secondary">JavaScript Code</label>
-						<p class="mt-1 text-xs text-theme-muted">
-							Arguments are passed as an <code class="bg-theme-tertiary px-1 rounded">args</code> object. Return the result.
+						<div class="flex items-center justify-between mb-1">
+							<label class="block text-sm font-medium text-theme-secondary">
+								{implementation === 'javascript' ? 'JavaScript' : 'Python'} Code
+							</label>
+							<div class="flex items-center gap-2">
+								<!-- Templates dropdown -->
+								<div class="relative">
+									<button
+										type="button"
+										onclick={() => showTemplates = !showTemplates}
+										class="flex items-center gap-1 text-xs text-blue-400 hover:text-blue-300"
+									>
+										<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+											<path d="M9 4.804A7.968 7.968 0 005.5 4c-1.255 0-2.443.29-3.5.804v10A7.969 7.969 0 015.5 14c1.669 0 3.218.51 4.5 1.385A7.962 7.962 0 0114.5 14c1.255 0 2.443.29 3.5.804v-10A7.968 7.968 0 0014.5 4c-1.255 0-2.443.29-3.5.804V12a1 1 0 11-2 0V4.804z" />
+										</svg>
+										Templates
+									</button>
+									{#if showTemplates && currentTemplates.length > 0}
+										<div class="absolute right-0 top-full mt-1 w-64 rounded-lg border border-theme-subtle bg-theme-secondary shadow-lg z-10">
+											<div class="p-2 space-y-1 max-h-48 overflow-y-auto">
+												{#each currentTemplates as template (template.id)}
+													<button
+														type="button"
+														onclick={() => applyTemplate(template)}
+														class="w-full text-left px-3 py-2 rounded hover:bg-theme-tertiary"
+													>
+														<div class="text-sm text-theme-primary">{template.name}</div>
+														<div class="text-xs text-theme-muted truncate">{template.description}</div>
+													</button>
+												{/each}
+											</div>
+										</div>
+									{/if}
+								</div>
+								<!-- Docs toggle -->
+								<button
+									type="button"
+									onclick={() => showDocs = !showDocs}
+									class="flex items-center gap-1 text-xs {showDocs ? 'text-emerald-400' : 'text-theme-muted hover:text-theme-secondary'}"
+								>
+									<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+										<path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7-4a1 1 0 11-2 0 1 1 0 012 0zM9 9a1 1 0 000 2v3a1 1 0 001 1h1a1 1 0 100-2v-3a1 1 0 00-1-1H9z" clip-rule="evenodd" />
+									</svg>
+									Docs
+								</button>
+							</div>
+						</div>
+						<p class="text-xs text-theme-muted mb-2">
+							{#if implementation === 'javascript'}
+								Arguments are passed as an <code class="bg-theme-tertiary px-1 rounded">args</code> object. Return the result.
+							{:else}
+								Arguments are available as <code class="bg-theme-tertiary px-1 rounded">args</code> dict. Print JSON result to stdout.
+							{/if}
 						</p>
-						<textarea
-							id="tool-code"
-							bind:value={code}
-							rows="8"
-							class="mt-2 w-full rounded-lg border border-theme-subtle bg-theme-primary px-3 py-2 font-mono text-sm text-theme-primary placeholder-theme-muted focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500"
-						></textarea>
+
+						<!-- Documentation panel -->
+						<ToolDocs
+							language={implementation}
+							isOpen={showDocs}
+							onclose={() => showDocs = false}
+						/>
+
+						<div class="mt-2">
+							<CodeEditor
+								bind:value={code}
+								language={implementation === 'python' ? 'python' : 'javascript'}
+								minHeight="200px"
+							/>
+						</div>
 						{#if errors.code}
 							<p class="mt-1 text-sm text-red-400">{errors.code}</p>
 						{/if}
+
+						<!-- Test button -->
+						<button
+							type="button"
+							onclick={() => showTest = !showTest}
+							class="mt-3 flex items-center gap-2 text-sm {showTest ? 'text-emerald-400' : 'text-theme-muted hover:text-theme-secondary'}"
+						>
+							<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+								<path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zM9.555 7.168A1 1 0 008 8v4a1 1 0 001.555.832l3-2a1 1 0 000-1.664l-3-2z" clip-rule="evenodd" />
+							</svg>
+							{showTest ? 'Hide Test Panel' : 'Test Tool'}
+						</button>
+
+						<!-- Tool tester -->
+						<ToolTester
+							{implementation}
+							{code}
+							parameters={buildParameterSchema()}
+							isOpen={showTest}
+							onclose={() => showTest = false}
+						/>
 					</div>
 				{/if}

--- a/frontend/src/lib/components/tools/ToolTester.svelte
+++ b/frontend/src/lib/components/tools/ToolTester.svelte
@@ -0,0 +1,220 @@
+<script lang="ts">
+	/**
+	 * ToolTester - Test panel for running tools with sample inputs
+	 */
+
+	import type { JSONSchema, ToolImplementation } from '$lib/tools';
+	import CodeEditor from './CodeEditor.svelte';
+
+	interface Props {
+		implementation: ToolImplementation;
+		code: string;
+		parameters: JSONSchema;
+		isOpen?: boolean;
+		onclose?: () => void;
+	}
+
+	const { implementation, code, parameters, isOpen = false, onclose }: Props = $props();
+
+	let testInput = $state('{}');
+	let testResult = $state<{ success: boolean; result?: unknown; error?: string } | null>(null);
+	let isRunning = $state(false);
+
+	// Generate example input from parameters
+	$effect(() => {
+		if (isOpen && testInput === '{}' && parameters.properties) {
+			const example: Record<string, unknown> = {};
+			for (const [name, prop] of Object.entries(parameters.properties)) {
+				switch (prop.type) {
+					case 'string':
+						example[name] = prop.description ? `example_${name}` : '';
+						break;
+					case 'number':
+						example[name] = 0;
+						break;
+					case 'boolean':
+						example[name] = false;
+						break;
+					case 'array':
+						example[name] = [];
+						break;
+					case 'object':
+						example[name] = {};
+						break;
+				}
+			}
+			if (Object.keys(example).length > 0) {
+				testInput = JSON.stringify(example, null, 2);
+			}
+		}
+	});
+
+	async function runTest(): Promise<void> {
+		if (isRunning) return;
+
+		isRunning = true;
+		testResult = null;
+
+		try {
+			// Parse the input
+			let args: Record<string, unknown>;
+			try {
+				args = JSON.parse(testInput);
+			} catch {
+				testResult = { success: false, error: 'Invalid JSON input' };
+				isRunning = false;
+				return;
+			}
+
+			if (implementation === 'javascript') {
+				// Execute JavaScript directly in browser
+				try {
+					// eslint-disable-next-line @typescript-eslint/no-implied-eval
+					const AsyncFunction = Object.getPrototypeOf(async function () {}).constructor;
+					const fn = new AsyncFunction(
+						'args',
+						`
+						"use strict";
+						${code}
+					`
+					);
+					const result = await fn(args);
+					testResult = { success: true, result };
+				} catch (error) {
+					testResult = {
+						success: false,
+						error: error instanceof Error ? error.message : String(error)
+					};
+				}
+			} else if (implementation === 'python') {
+				// Python requires backend execution
+				try {
+					const response = await fetch('/api/v1/tools/execute', {
+						method: 'POST',
+						headers: { 'Content-Type': 'application/json' },
+						body: JSON.stringify({
+							language: 'python',
+							code,
+							args,
+							timeout: 30
+						})
+					});
+
+					if (!response.ok) {
+						throw new Error(`Server error: ${response.status}`);
+					}
+
+					const data = await response.json();
+					if (data.success) {
+						testResult = { success: true, result: data.result };
+					} else {
+						testResult = { success: false, error: data.error || 'Unknown error' };
+					}
+				} catch (error) {
+					testResult = {
+						success: false,
+						error: error instanceof Error ? error.message : String(error)
+					};
+				}
+			} else {
+				testResult = { success: false, error: 'HTTP tools cannot be tested in the editor' };
+			}
+		} finally {
+			isRunning = false;
+		}
+	}
+
+	function formatResult(result: unknown): string {
+		if (result === undefined) return 'undefined';
+		if (result === null) return 'null';
+		try {
+			return JSON.stringify(result, null, 2);
+		} catch {
+			return String(result);
+		}
+	}
+</script>
+
+{#if isOpen}
+	<div class="rounded-lg border border-theme-subtle bg-theme-tertiary/50 p-4 mt-4">
+		<div class="flex items-center justify-between mb-3">
+			<h4 class="text-sm font-medium text-theme-primary flex items-center gap-2">
+				<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+					<path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zM9.555 7.168A1 1 0 008 8v4a1 1 0 001.555.832l3-2a1 1 0 000-1.664l-3-2z" clip-rule="evenodd" />
+				</svg>
+				Test Tool
+			</h4>
+			{#if onclose}
+				<button
+					type="button"
+					onclick={onclose}
+					class="text-theme-muted hover:text-theme-primary"
+					aria-label="Close test panel"
+				>
+					<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+						<path fill-rule="evenodd" d="M4.293 4.293a1 1 0 011.414 0L10 8.586l4.293-4.293a1 1 0 111.414 1.414L11.414 10l4.293 4.293a1 1 0 01-1.414 1.414L10 11.414l-4.293 4.293a1 1 0 01-1.414-1.414L8.586 10 4.293 5.707a1 1 0 010-1.414z" clip-rule="evenodd" />
+					</svg>
+				</button>
+			{/if}
+		</div>
+
+		<div class="space-y-4">
+			<!-- Input -->
+			<div>
+				<label class="block text-xs font-medium text-theme-secondary mb-1">Input Arguments (JSON)</label>
+				<CodeEditor bind:value={testInput} language="json" minHeight="80px" />
+			</div>
+
+			<!-- Run button -->
+			<button
+				type="button"
+				onclick={runTest}
+				disabled={isRunning || !code.trim()}
+				class="flex items-center gap-2 px-3 py-1.5 text-sm font-medium rounded-lg bg-emerald-600 text-white hover:bg-emerald-500 disabled:opacity-50 disabled:cursor-not-allowed"
+			>
+				{#if isRunning}
+					<svg class="animate-spin h-4 w-4" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
+						<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+						<path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
+					</svg>
+					Running...
+				{:else}
+					<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+						<path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zM9.555 7.168A1 1 0 008 8v4a1 1 0 001.555.832l3-2a1 1 0 000-1.664l-3-2z" clip-rule="evenodd" />
+					</svg>
+					Run Test
+				{/if}
+			</button>
+
+			<!-- Result -->
+			{#if testResult}
+				<div>
+					<label class="block text-xs font-medium text-theme-secondary mb-1">Result</label>
+					<div
+						class="rounded-lg p-3 text-sm font-mono overflow-x-auto {testResult.success
+							? 'bg-emerald-900/30 border border-emerald-500/30'
+							: 'bg-red-900/30 border border-red-500/30'}"
+					>
+						{#if testResult.success}
+							<div class="flex items-center gap-2 text-emerald-400 mb-2">
+								<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+									<path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zm3.707-9.293a1 1 0 00-1.414-1.414L9 10.586 7.707 9.293a1 1 0 00-1.414 1.414l2 2a1 1 0 001.414 0l4-4z" clip-rule="evenodd" />
+								</svg>
+								Success
+							</div>
+							<pre class="text-theme-primary whitespace-pre-wrap">{formatResult(testResult.result)}</pre>
+						{:else}
+							<div class="flex items-center gap-2 text-red-400 mb-2">
+								<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4" viewBox="0 0 20 20" fill="currentColor">
+									<path fill-rule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zM8.707 7.293a1 1 0 00-1.414 1.414L8.586 10l-1.293 1.293a1 1 0 101.414 1.414L10 11.414l1.293 1.293a1 1 0 001.414-1.414L11.414 10l1.293-1.293a1 1 0 00-1.414-1.414L10 8.586 8.707 7.293z" clip-rule="evenodd" />
+								</svg>
+								Error
+							</div>
+							<pre class="text-red-300 whitespace-pre-wrap">{testResult.error}</pre>
+						{/if}
+					</div>
+				</div>
+			{/if}
+		</div>
+	</div>
+{/if}
--- a/frontend/src/lib/components/tools/index.ts
+++ b/frontend/src/lib/components/tools/index.ts
@@ -2,4 +2,7 @@
 * Tools components exports
 */

+export { default as CodeEditor } from './CodeEditor.svelte';
+export { default as ToolDocs } from './ToolDocs.svelte';
 export { default as ToolEditor } from './ToolEditor.svelte';
+export { default as ToolTester } from './ToolTester.svelte';
--- a/frontend/src/lib/tools/executor.ts
+++ b/frontend/src/lib/tools/executor.ts
@@ -41,6 +41,45 @@ async function executeJavaScriptTool(tool: CustomTool, args: Record<string, unkn
 	}
 }

+/**
+ * Execute a custom Python tool via backend API
+ *
+ * SECURITY NOTE: This sends user-provided Python code to the backend for execution.
+ * This is by design - users create custom tools with their own code.
+ * The backend executes code in a subprocess with timeout protection.
+ */
+async function executePythonTool(tool: CustomTool, args: Record<string, unknown>): Promise<unknown> {
+	if (!tool.code) {
+		throw new Error('Python tool has no code');
+	}
+
+	try {
+		const response = await fetch('/api/v1/tools/execute', {
+			method: 'POST',
+			headers: { 'Content-Type': 'application/json' },
+			body: JSON.stringify({
+				language: 'python',
+				code: tool.code,
+				args,
+				timeout: 30
+			})
+		});
+
+		if (!response.ok) {
+			throw new Error(`Backend error: ${response.status} ${response.statusText}`);
+		}
+
+		const data = await response.json();
+		if (!data.success) {
+			throw new Error(data.error || 'Python execution failed');
+		}
+
+		return data.result;
+	} catch (error) {
+		throw new Error(`Python tool error: ${error instanceof Error ? error.message : String(error)}`);
+	}
+}
+
 /**
 * Execute a custom HTTP tool
 */
@@ -168,6 +207,8 @@ export async function executeCustomTool(
 	switch (tool.implementation) {
 		case 'javascript':
 			return executeJavaScriptTool(tool, args);
+		case 'python':
+			return executePythonTool(tool, args);
 		case 'http':
 			return executeHttpTool(tool, args);
 		default:
--- a/frontend/src/lib/tools/index.ts
+++ b/frontend/src/lib/tools/index.ts
@@ -21,3 +21,10 @@ export {
 	defaultToolConfig,
 	type ToolConfig
 } from './config.js';
+export {
+	toolTemplates,
+	getTemplatesByLanguage,
+	getTemplatesByCategory,
+	getTemplateById,
+	type ToolTemplate
+} from './templates.js';
--- a/frontend/src/lib/tools/templates.ts
+++ b/frontend/src/lib/tools/templates.ts
@@ -0,0 +1,352 @@
+/**
+ * Tool templates - Starter templates for custom tools
+ */
+
+import type { JSONSchema, ToolImplementation } from './types';
+
+export interface ToolTemplate {
+	id: string;
+	name: string;
+	description: string;
+	category: 'api' | 'data' | 'utility' | 'integration';
+	language: ToolImplementation;
+	code: string;
+	parameters: JSONSchema;
+}
+
+export const toolTemplates: ToolTemplate[] = [
+	// JavaScript Templates
+	{
+		id: 'js-api-fetch',
+		name: 'API Request',
+		description: 'Fetch data from an external REST API',
+		category: 'api',
+		language: 'javascript',
+		code: `// Fetch data from an API endpoint
+const response = await fetch(args.url, {
+  method: args.method || 'GET',
+  headers: {
+    'Content-Type': 'application/json',
+    ...(args.headers || {})
+  },
+  ...(args.body ? { body: JSON.stringify(args.body) } : {})
+});
+
+if (!response.ok) {
+  throw new Error(\`HTTP \${response.status}: \${response.statusText}\`);
+}
+
+return await response.json();`,
+		parameters: {
+			type: 'object',
+			properties: {
+				url: { type: 'string', description: 'The API endpoint URL' },
+				method: { type: 'string', description: 'HTTP method (GET, POST, etc.)' },
+				headers: { type: 'object', description: 'Additional headers' },
+				body: { type: 'object', description: 'Request body for POST/PUT' }
+			},
+			required: ['url']
+		}
+	},
+	{
+		id: 'js-json-transform',
+		name: 'JSON Transform',
+		description: 'Transform and filter JSON data',
+		category: 'data',
+		language: 'javascript',
+		code: `// Transform JSON data
+const data = args.data;
+const fields = args.fields || Object.keys(data[0] || data);
+
+// Handle both arrays and single objects
+const items = Array.isArray(data) ? data : [data];
+
+const result = items.map(item => {
+  const filtered = {};
+  for (const field of fields) {
+    if (field in item) {
+      filtered[field] = item[field];
+    }
+  }
+  return filtered;
+});
+
+return Array.isArray(data) ? result : result[0];`,
+		parameters: {
+			type: 'object',
+			properties: {
+				data: { type: 'object', description: 'JSON data to transform' },
+				fields: { type: 'array', description: 'Fields to keep (optional)' }
+			},
+			required: ['data']
+		}
+	},
+	{
+		id: 'js-string-utils',
+		name: 'String Utilities',
+		description: 'Common string manipulation operations',
+		category: 'utility',
+		language: 'javascript',
+		code: `// String manipulation utilities
+const text = args.text;
+const operation = args.operation;
+
+switch (operation) {
+  case 'uppercase':
+    return text.toUpperCase();
+  case 'lowercase':
+    return text.toLowerCase();
+  case 'capitalize':
+    return text.charAt(0).toUpperCase() + text.slice(1).toLowerCase();
+  case 'reverse':
+    return text.split('').reverse().join('');
+  case 'word_count':
+    return { count: text.split(/\\s+/).filter(w => w).length };
+  case 'char_count':
+    return { count: text.length };
+  case 'slug':
+    return text.toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '');
+  default:
+    return { text, error: 'Unknown operation' };
+}`,
+		parameters: {
+			type: 'object',
+			properties: {
+				text: { type: 'string', description: 'Input text to process' },
+				operation: { type: 'string', description: 'Operation: uppercase, lowercase, capitalize, reverse, word_count, char_count, slug' }
+			},
+			required: ['text', 'operation']
+		}
+	},
+	{
+		id: 'js-date-utils',
+		name: 'Date Utilities',
+		description: 'Date formatting and calculations',
+		category: 'utility',
+		language: 'javascript',
+		code: `// Date utilities
+const date = args.date ? new Date(args.date) : new Date();
+const format = args.format || 'iso';
+
+const formatDate = (d, fmt) => {
+  const pad = n => String(n).padStart(2, '0');
+
+  switch (fmt) {
+    case 'iso':
+      return d.toISOString();
+    case 'date':
+      return d.toLocaleDateString();
+    case 'time':
+      return d.toLocaleTimeString();
+    case 'unix':
+      return Math.floor(d.getTime() / 1000);
+    case 'relative':
+      const diff = Date.now() - d.getTime();
+      const mins = Math.floor(diff / 60000);
+      if (mins < 60) return \`\${mins} minutes ago\`;
+      const hours = Math.floor(mins / 60);
+      if (hours < 24) return \`\${hours} hours ago\`;
+      return \`\${Math.floor(hours / 24)} days ago\`;
+    default:
+      return d.toISOString();
+  }
+};
+
+return {
+  formatted: formatDate(date, format),
+  timestamp: date.getTime(),
+  iso: date.toISOString()
+};`,
+		parameters: {
+			type: 'object',
+			properties: {
+				date: { type: 'string', description: 'Date string or timestamp (default: now)' },
+				format: { type: 'string', description: 'Format: iso, date, time, unix, relative' }
+			}
+		}
+	},
+
+	// Python Templates
+	{
+		id: 'py-api-fetch',
+		name: 'API Request (Python)',
+		description: 'Fetch data from an external REST API using Python',
+		category: 'api',
+		language: 'python',
+		code: `# Fetch data from an API endpoint
+import json
+import urllib.request
+import urllib.error
+
+url = args.get('url')
+method = args.get('method', 'GET')
+headers = args.get('headers', {})
+body = args.get('body')
+
+req = urllib.request.Request(url, method=method)
+req.add_header('Content-Type', 'application/json')
+for key, value in headers.items():
+    req.add_header(key, value)
+
+data = json.dumps(body).encode() if body else None
+
+try:
+    with urllib.request.urlopen(req, data=data) as response:
+        result = json.loads(response.read().decode())
+        print(json.dumps(result))
+except urllib.error.HTTPError as e:
+    print(json.dumps({"error": f"HTTP {e.code}: {e.reason}"}))`,
+		parameters: {
+			type: 'object',
+			properties: {
+				url: { type: 'string', description: 'The API endpoint URL' },
+				method: { type: 'string', description: 'HTTP method (GET, POST, etc.)' },
+				headers: { type: 'object', description: 'Additional headers' },
+				body: { type: 'object', description: 'Request body for POST/PUT' }
+			},
+			required: ['url']
+		}
+	},
+	{
+		id: 'py-data-analysis',
+		name: 'Data Analysis (Python)',
+		description: 'Basic statistical analysis of numeric data',
+		category: 'data',
+		language: 'python',
+		code: `# Basic data analysis
+import json
+import math
+
+data = args.get('data', [])
+if not data:
+    print(json.dumps({"error": "No data provided"}))
+else:
+    n = len(data)
+    total = sum(data)
+    mean = total / n
+
+    sorted_data = sorted(data)
+    mid = n // 2
+    median = sorted_data[mid] if n % 2 else (sorted_data[mid-1] + sorted_data[mid]) / 2
+
+    variance = sum((x - mean) ** 2 for x in data) / n
+    std_dev = math.sqrt(variance)
+
+    result = {
+        "count": n,
+        "sum": total,
+        "mean": round(mean, 4),
+        "median": median,
+        "min": min(data),
+        "max": max(data),
+        "std_dev": round(std_dev, 4),
+        "variance": round(variance, 4)
+    }
+    print(json.dumps(result))`,
+		parameters: {
+			type: 'object',
+			properties: {
+				data: { type: 'array', description: 'Array of numbers to analyze' }
+			},
+			required: ['data']
+		}
+	},
+	{
+		id: 'py-text-analysis',
+		name: 'Text Analysis (Python)',
+		description: 'Analyze text for word frequency, sentiment indicators',
+		category: 'data',
+		language: 'python',
+		code: `# Text analysis
+import json
+import re
+from collections import Counter
+
+text = args.get('text', '')
+top_n = args.get('top_n', 10)
+
+# Tokenize and count
+words = re.findall(r'\\b\\w+\\b', text.lower())
+word_freq = Counter(words)
+
+# Basic stats
+sentences = re.split(r'[.!?]+', text)
+sentences = [s.strip() for s in sentences if s.strip()]
+
+result = {
+    "word_count": len(words),
+    "unique_words": len(word_freq),
+    "sentence_count": len(sentences),
+    "avg_word_length": round(sum(len(w) for w in words) / len(words), 2) if words else 0,
+    "top_words": dict(word_freq.most_common(top_n)),
+    "char_count": len(text),
+    "char_count_no_spaces": len(text.replace(' ', ''))
+}
+print(json.dumps(result))`,
+		parameters: {
+			type: 'object',
+			properties: {
+				text: { type: 'string', description: 'Text to analyze' },
+				top_n: { type: 'number', description: 'Number of top words to return (default: 10)' }
+			},
+			required: ['text']
+		}
+	},
+	{
+		id: 'py-hash-encode',
+		name: 'Hash & Encode (Python)',
+		description: 'Hash strings and encode/decode base64',
+		category: 'utility',
+		language: 'python',
+		code: `# Hash and encoding utilities
+import json
+import hashlib
+import base64
+
+text = args.get('text', '')
+operation = args.get('operation', 'md5')
+
+result = {}
+
+if operation == 'md5':
+    result['hash'] = hashlib.md5(text.encode()).hexdigest()
+elif operation == 'sha256':
+    result['hash'] = hashlib.sha256(text.encode()).hexdigest()
+elif operation == 'sha512':
+    result['hash'] = hashlib.sha512(text.encode()).hexdigest()
+elif operation == 'base64_encode':
+    result['encoded'] = base64.b64encode(text.encode()).decode()
+elif operation == 'base64_decode':
+    try:
+        result['decoded'] = base64.b64decode(text.encode()).decode()
+    except Exception as e:
+        result['error'] = str(e)
+else:
+    result['error'] = f'Unknown operation: {operation}'
+
+result['operation'] = operation
+result['input_length'] = len(text)
+
+print(json.dumps(result))`,
+		parameters: {
+			type: 'object',
+			properties: {
+				text: { type: 'string', description: 'Text to process' },
+				operation: { type: 'string', description: 'Operation: md5, sha256, sha512, base64_encode, base64_decode' }
+			},
+			required: ['text', 'operation']
+		}
+	}
+];
+
+export function getTemplatesByLanguage(language: ToolImplementation): ToolTemplate[] {
+	return toolTemplates.filter(t => t.language === language);
+}
+
+export function getTemplatesByCategory(category: ToolTemplate['category']): ToolTemplate[] {
+	return toolTemplates.filter(t => t.category === category);
+}
+
+export function getTemplateById(id: string): ToolTemplate | undefined {
+	return toolTemplates.find(t => t.id === id);
+}
--- a/frontend/src/lib/tools/types.ts
+++ b/frontend/src/lib/tools/types.ts
@@ -54,7 +54,7 @@ export interface ToolResult {
 }

 /** Tool implementation type */
-export type ToolImplementation = 'builtin' | 'javascript' | 'http';
+export type ToolImplementation = 'builtin' | 'javascript' | 'python' | 'http';

 /** Custom tool configuration */
 export interface CustomTool {
@@ -63,7 +63,7 @@ export interface CustomTool {
 	description: string;
 	parameters: JSONSchema;
 	implementation: ToolImplementation;
-	/** JavaScript code for 'javascript' implementation */
+	/** Code for 'javascript' or 'python' implementation */
 	code?: string;
 	/** HTTP endpoint for 'http' implementation */
 	endpoint?: string;
Author	SHA1	Message	Date
vikingowl	a552f4a223	chore: bump version to 0.4.1 Some checks failed Create Release / release (push) Has been cancelled Details	2026-01-02 20:36:03 +01:00
vikingowl	4a9e45b40b	fix: persist toolCalls to database for reload persistence Tool usage was not showing after page reload because the toolCalls field was not being included when saving assistant messages to the database. Now toolCalls are properly persisted and restored.	2026-01-02 20:34:53 +01:00
vikingowl	862f47c46e	feat(tools): enhanced custom tool creation with CodeMirror, Python support, and testing Some checks failed Create Release / release (push) Has been cancelled Details - Add CodeMirror editor with syntax highlighting for JavaScript and Python - Add 8 starter templates (4 JS, 4 Python) for common tool patterns - Add inline documentation panel with language-specific guidance - Add tool testing UI to run tools with sample inputs before saving - Add Python tool execution via backend API with 30s timeout - Add POST /api/v1/tools/execute endpoint for backend tool execution - Update Dockerfile to include Python 3 for tool execution - Bump version to 0.4.0	2026-01-02 20:15:40 +01:00
vikingowl	5572cd3a0d	ci: auto-create GitHub release on tag push	2026-01-02 19:46:29 +01:00
vikingowl	6426850714	chore: add CLAUDE.md to gitignore	2026-01-02 19:42:47 +01:00