1package tools
2
3import (
4 "bytes"
5 "cmp"
6 "context"
7 _ "embed"
8 "fmt"
9 "html/template"
10 "os"
11 "path/filepath"
12 "runtime"
13 "strings"
14 "time"
15
16 "charm.land/fantasy"
17 "github.com/charmbracelet/crush/internal/config"
18 "github.com/charmbracelet/crush/internal/permission"
19 "github.com/charmbracelet/crush/internal/shell"
20)
21
22type BashParams struct {
23 Description string `json:"description" description:"A brief description of what the command does, try to keep it under 30 characters or so"`
24 Command string `json:"command" description:"The command to execute"`
25 WorkingDir string `json:"working_dir,omitempty" description:"The working directory to execute the command in (defaults to current directory)"`
26 RunInBackground bool `json:"run_in_background,omitempty" description:"Set to true (boolean) to run this command in the background. Use job_output to read the output later."`
27}
28
29type BashPermissionsParams struct {
30 Description string `json:"description"`
31 Command string `json:"command"`
32 WorkingDir string `json:"working_dir"`
33 RunInBackground bool `json:"run_in_background"`
34}
35
36type BashResponseMetadata struct {
37 StartTime int64 `json:"start_time"`
38 EndTime int64 `json:"end_time"`
39 Output string `json:"output"`
40 Description string `json:"description"`
41 WorkingDirectory string `json:"working_directory"`
42 Background bool `json:"background,omitempty"`
43 ShellID string `json:"shell_id,omitempty"`
44}
45
46const (
47 BashToolName = "bash"
48
49 AutoBackgroundThreshold = 1 * time.Minute // Commands taking longer automatically become background jobs
50 MaxOutputLength = 30000
51 BashNoOutput = "no output"
52)
53
54//go:embed bash.tpl
55var bashDescriptionTmpl []byte
56
57var bashDescriptionTpl = template.Must(
58 template.New("bashDescription").
59 Parse(string(bashDescriptionTmpl)),
60)
61
62type bashDescriptionData struct {
63 BannedCommands string
64 MaxOutputLength int
65 Attribution config.Attribution
66 ModelName string
67}
68
69var defaultBannedCommands = []string{
70 // Network/Download tools
71 "alias",
72 "aria2c",
73 "axel",
74 "chrome",
75 "curl",
76 "curlie",
77 "firefox",
78 "http-prompt",
79 "httpie",
80 "links",
81 "lynx",
82 "nc",
83 "safari",
84 "scp",
85 "ssh",
86 "telnet",
87 "w3m",
88 "wget",
89 "xh",
90
91 // System administration
92 "doas",
93 "su",
94 "sudo",
95
96 // Package managers
97 "apk",
98 "apt",
99 "apt-cache",
100 "apt-get",
101 "dnf",
102 "dpkg",
103 "emerge",
104 "home-manager",
105 "makepkg",
106 "opkg",
107 "pacman",
108 "paru",
109 "pkg",
110 "pkg_add",
111 "pkg_delete",
112 "portage",
113 "rpm",
114 "yay",
115 "yum",
116 "zypper",
117
118 // System modification
119 "at",
120 "batch",
121 "chkconfig",
122 "crontab",
123 "fdisk",
124 "mkfs",
125 "mount",
126 "parted",
127 "service",
128 "systemctl",
129 "umount",
130
131 // Network configuration
132 "firewall-cmd",
133 "ifconfig",
134 "ip",
135 "iptables",
136 "netstat",
137 "pfctl",
138 "route",
139 "ufw",
140}
141
142func bashDescription(attribution *config.Attribution, modelName string) string {
143 bannedCommandsStr := strings.Join(defaultBannedCommands, ", ")
144 var out bytes.Buffer
145 if err := bashDescriptionTpl.Execute(&out, bashDescriptionData{
146 BannedCommands: bannedCommandsStr,
147 MaxOutputLength: MaxOutputLength,
148 Attribution: *attribution,
149 ModelName: modelName,
150 }); err != nil {
151 // this should never happen.
152 panic("failed to execute bash description template: " + err.Error())
153 }
154 return out.String()
155}
156
157func blockFuncs(bannedCommands []string) []shell.BlockFunc {
158 return []shell.BlockFunc{
159 shell.CommandsBlocker(bannedCommands),
160
161 // System package managers
162 shell.ArgumentsBlocker("apk", []string{"add"}, nil),
163 shell.ArgumentsBlocker("apt", []string{"install"}, nil),
164 shell.ArgumentsBlocker("apt-get", []string{"install"}, nil),
165 shell.ArgumentsBlocker("dnf", []string{"install"}, nil),
166 shell.ArgumentsBlocker("pacman", nil, []string{"-S"}),
167 shell.ArgumentsBlocker("pkg", []string{"install"}, nil),
168 shell.ArgumentsBlocker("yum", []string{"install"}, nil),
169 shell.ArgumentsBlocker("zypper", []string{"install"}, nil),
170
171 // Language-specific package managers
172 shell.ArgumentsBlocker("brew", []string{"install"}, nil),
173 shell.ArgumentsBlocker("cargo", []string{"install"}, nil),
174 shell.ArgumentsBlocker("gem", []string{"install"}, nil),
175 shell.ArgumentsBlocker("go", []string{"install"}, nil),
176 shell.ArgumentsBlocker("npm", []string{"install"}, []string{"--global"}),
177 shell.ArgumentsBlocker("npm", []string{"install"}, []string{"-g"}),
178 shell.ArgumentsBlocker("pip", []string{"install"}, []string{"--user"}),
179 shell.ArgumentsBlocker("pip3", []string{"install"}, []string{"--user"}),
180 shell.ArgumentsBlocker("pnpm", []string{"add"}, []string{"--global"}),
181 shell.ArgumentsBlocker("pnpm", []string{"add"}, []string{"-g"}),
182 shell.ArgumentsBlocker("yarn", []string{"global", "add"}, nil),
183
184 // `go test -exec` can run arbitrary commands
185 shell.ArgumentsBlocker("go", []string{"test"}, []string{"-exec"}),
186 }
187}
188
189func resolveBlockFuncs(cfg config.ToolBash) []shell.BlockFunc {
190 bannedCommands := cfg.BannedCommands
191 if !cfg.DisableDefaults {
192 if len(bannedCommands) == 0 {
193 return blockFuncs(defaultBannedCommands)
194 }
195 bannedCommands = append(bannedCommands, defaultBannedCommands...)
196 }
197 return blockFuncs(bannedCommands)
198}
199
200func NewBashTool(
201 permissions permission.Service,
202 workingDir string, attribution *config.Attribution,
203 modelName string,
204 bashConfig config.ToolBash,
205) fantasy.AgentTool {
206 return fantasy.NewAgentTool(
207 BashToolName,
208 string(bashDescription(attribution, modelName)),
209 func(ctx context.Context, params BashParams, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
210 if params.Command == "" {
211 return fantasy.NewTextErrorResponse("missing command"), nil
212 }
213
214 // Determine working directory
215 execWorkingDir := cmp.Or(params.WorkingDir, workingDir)
216
217 isSafeReadOnly := false
218 cmdLower := strings.ToLower(params.Command)
219
220 for _, safe := range safeCommands {
221 if strings.HasPrefix(cmdLower, safe) {
222 if len(cmdLower) == len(safe) || cmdLower[len(safe)] == ' ' || cmdLower[len(safe)] == '-' {
223 isSafeReadOnly = true
224 break
225 }
226 }
227 }
228
229 sessionID := GetSessionFromContext(ctx)
230 if sessionID == "" {
231 return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for executing shell command")
232 }
233 if !isSafeReadOnly {
234 p := permissions.Request(
235 permission.CreatePermissionRequest{
236 SessionID: sessionID,
237 Path: execWorkingDir,
238 ToolCallID: call.ID,
239 ToolName: BashToolName,
240 Action: "execute",
241 Description: fmt.Sprintf("Execute command: %s", params.Command),
242 Params: BashPermissionsParams(params),
243 },
244 )
245 if !p {
246 return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
247 }
248 }
249
250 // If explicitly requested as background, start immediately with detached context
251 if params.RunInBackground {
252 startTime := time.Now()
253 bgManager := shell.GetBackgroundShellManager()
254 bgManager.Cleanup()
255 // Use background context so it continues after tool returns
256 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, resolveBlockFuncs(bashConfig), params.Command, params.Description)
257 if err != nil {
258 return fantasy.ToolResponse{}, fmt.Errorf("error starting background shell: %w", err)
259 }
260
261 // Wait a short time to detect fast failures (blocked commands, syntax errors, etc.)
262 time.Sleep(1 * time.Second)
263 stdout, stderr, done, execErr := bgShell.GetOutput()
264
265 if done {
266 // Command failed or completed very quickly
267 bgManager.Remove(bgShell.ID)
268
269 interrupted := shell.IsInterrupt(execErr)
270 exitCode := shell.ExitCode(execErr)
271 if exitCode == 0 && !interrupted && execErr != nil {
272 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
273 }
274
275 stdout = formatOutput(stdout, stderr, execErr)
276
277 metadata := BashResponseMetadata{
278 StartTime: startTime.UnixMilli(),
279 EndTime: time.Now().UnixMilli(),
280 Output: stdout,
281 Description: params.Description,
282 Background: params.RunInBackground,
283 WorkingDirectory: bgShell.WorkingDir,
284 }
285 if stdout == "" {
286 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
287 }
288 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
289 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
290 }
291
292 // Still running after fast-failure check - return as background job
293 metadata := BashResponseMetadata{
294 StartTime: startTime.UnixMilli(),
295 EndTime: time.Now().UnixMilli(),
296 Description: params.Description,
297 WorkingDirectory: bgShell.WorkingDir,
298 Background: true,
299 ShellID: bgShell.ID,
300 }
301 response := fmt.Sprintf("Background shell started with ID: %s\n\nUse job_output tool to view output or job_kill to terminate.", bgShell.ID)
302 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
303 }
304
305 // Start synchronous execution with auto-background support
306 startTime := time.Now()
307
308 // Start with detached context so it can survive if moved to background
309 bgManager := shell.GetBackgroundShellManager()
310 bgManager.Cleanup()
311 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, blockFuncs(defaultBannedCommands), params.Command, params.Description)
312 if err != nil {
313 return fantasy.ToolResponse{}, fmt.Errorf("error starting shell: %w", err)
314 }
315
316 // Wait for either completion, auto-background threshold, or context cancellation
317 ticker := time.NewTicker(100 * time.Millisecond)
318 defer ticker.Stop()
319 timeout := time.After(AutoBackgroundThreshold)
320
321 var stdout, stderr string
322 var done bool
323 var execErr error
324
325 waitLoop:
326 for {
327 select {
328 case <-ticker.C:
329 stdout, stderr, done, execErr = bgShell.GetOutput()
330 if done {
331 break waitLoop
332 }
333 case <-timeout:
334 stdout, stderr, done, execErr = bgShell.GetOutput()
335 break waitLoop
336 case <-ctx.Done():
337 // Incoming context was cancelled before we moved to background
338 // Kill the shell and return error
339 bgManager.Kill(bgShell.ID)
340 return fantasy.ToolResponse{}, ctx.Err()
341 }
342 }
343
344 if done {
345 // Command completed within threshold - return synchronously
346 // Remove from background manager since we're returning directly
347 // Don't call Kill() as it cancels the context and corrupts the exit code
348 bgManager.Remove(bgShell.ID)
349
350 interrupted := shell.IsInterrupt(execErr)
351 exitCode := shell.ExitCode(execErr)
352 if exitCode == 0 && !interrupted && execErr != nil {
353 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
354 }
355
356 stdout = formatOutput(stdout, stderr, execErr)
357
358 metadata := BashResponseMetadata{
359 StartTime: startTime.UnixMilli(),
360 EndTime: time.Now().UnixMilli(),
361 Output: stdout,
362 Description: params.Description,
363 Background: params.RunInBackground,
364 WorkingDirectory: bgShell.WorkingDir,
365 }
366 if stdout == "" {
367 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
368 }
369 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
370 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
371 }
372
373 // Still running - keep as background job
374 metadata := BashResponseMetadata{
375 StartTime: startTime.UnixMilli(),
376 EndTime: time.Now().UnixMilli(),
377 Description: params.Description,
378 WorkingDirectory: bgShell.WorkingDir,
379 Background: true,
380 ShellID: bgShell.ID,
381 }
382 response := fmt.Sprintf("Command is taking longer than expected and has been moved to background.\n\nBackground shell ID: %s\n\nUse job_output tool to view output or job_kill to terminate.", bgShell.ID)
383 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
384 })
385}
386
387// formatOutput formats the output of a completed command with error handling
388func formatOutput(stdout, stderr string, execErr error) string {
389 interrupted := shell.IsInterrupt(execErr)
390 exitCode := shell.ExitCode(execErr)
391
392 stdout = truncateOutput(stdout)
393 stderr = truncateOutput(stderr)
394
395 errorMessage := stderr
396 if errorMessage == "" && execErr != nil {
397 errorMessage = execErr.Error()
398 }
399
400 if interrupted {
401 if errorMessage != "" {
402 errorMessage += "\n"
403 }
404 errorMessage += "Command was aborted before completion"
405 } else if exitCode != 0 {
406 if errorMessage != "" {
407 errorMessage += "\n"
408 }
409 errorMessage += fmt.Sprintf("Exit code %d", exitCode)
410 }
411
412 hasBothOutputs := stdout != "" && stderr != ""
413
414 if hasBothOutputs {
415 stdout += "\n"
416 }
417
418 if errorMessage != "" {
419 stdout += "\n" + errorMessage
420 }
421
422 return stdout
423}
424
425func truncateOutput(content string) string {
426 if len(content) <= MaxOutputLength {
427 return content
428 }
429
430 halfLength := MaxOutputLength / 2
431 start := content[:halfLength]
432 end := content[len(content)-halfLength:]
433
434 truncatedLinesCount := countLines(content[halfLength : len(content)-halfLength])
435 return fmt.Sprintf("%s\n\n... [%d lines truncated] ...\n\n%s", start, truncatedLinesCount, end)
436}
437
438func countLines(s string) int {
439 if s == "" {
440 return 0
441 }
442 return len(strings.Split(s, "\n"))
443}
444
445func normalizeWorkingDir(path string) string {
446 if runtime.GOOS == "windows" {
447 cwd, err := os.Getwd()
448 if err != nil {
449 cwd = "C:"
450 }
451 path = strings.ReplaceAll(path, filepath.VolumeName(cwd), "")
452 }
453
454 return filepath.ToSlash(path)
455}