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 resolveBannedCommandsList(cfg config.ToolBash) []string {
190 bannedCommands := cfg.BannedCommands
191 if !cfg.DisableDefaults {
192 if len(bannedCommands) == 0 {
193 return defaultBannedCommands
194 }
195 bannedCommands = append(bannedCommands, defaultBannedCommands...)
196 }
197 return bannedCommands
198}
199
200func resolveBlockFuncs(cfg config.ToolBash) []shell.BlockFunc {
201 return blockFuncs(resolveBannedCommandsList(cfg))
202}
203
204func NewBashTool(
205 permissions permission.Service,
206 workingDir string, attribution *config.Attribution,
207 modelName string,
208 bashConfig config.ToolBash,
209) fantasy.AgentTool {
210 return fantasy.NewAgentTool(
211 BashToolName,
212 string(bashDescription(attribution, modelName)),
213 func(ctx context.Context, params BashParams, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
214 if params.Command == "" {
215 return fantasy.NewTextErrorResponse("missing command"), nil
216 }
217
218 // Determine working directory
219 execWorkingDir := cmp.Or(params.WorkingDir, workingDir)
220
221 isSafeReadOnly := false
222 cmdLower := strings.ToLower(params.Command)
223
224 for _, safe := range safeCommands {
225 if strings.HasPrefix(cmdLower, safe) {
226 if len(cmdLower) == len(safe) || cmdLower[len(safe)] == ' ' || cmdLower[len(safe)] == '-' {
227 isSafeReadOnly = true
228 break
229 }
230 }
231 }
232
233 sessionID := GetSessionFromContext(ctx)
234 if sessionID == "" {
235 return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for executing shell command")
236 }
237 if !isSafeReadOnly {
238 p := permissions.Request(
239 permission.CreatePermissionRequest{
240 SessionID: sessionID,
241 Path: execWorkingDir,
242 ToolCallID: call.ID,
243 ToolName: BashToolName,
244 Action: "execute",
245 Description: fmt.Sprintf("Execute command: %s", params.Command),
246 Params: BashPermissionsParams(params),
247 },
248 )
249 if !p {
250 return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
251 }
252 }
253
254 // If explicitly requested as background, start immediately with detached context
255 if params.RunInBackground {
256 startTime := time.Now()
257 bgManager := shell.GetBackgroundShellManager()
258 bgManager.Cleanup()
259 // Use background context so it continues after tool returns
260 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, resolveBlockFuncs(bashConfig), params.Command, params.Description)
261 if err != nil {
262 return fantasy.ToolResponse{}, fmt.Errorf("error starting background shell: %w", err)
263 }
264
265 // Wait a short time to detect fast failures (blocked commands, syntax errors, etc.)
266 time.Sleep(1 * time.Second)
267 stdout, stderr, done, execErr := bgShell.GetOutput()
268
269 if done {
270 // Command failed or completed very quickly
271 bgManager.Remove(bgShell.ID)
272
273 interrupted := shell.IsInterrupt(execErr)
274 exitCode := shell.ExitCode(execErr)
275 if exitCode == 0 && !interrupted && execErr != nil {
276 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
277 }
278
279 stdout = formatOutput(stdout, stderr, execErr)
280
281 metadata := BashResponseMetadata{
282 StartTime: startTime.UnixMilli(),
283 EndTime: time.Now().UnixMilli(),
284 Output: stdout,
285 Description: params.Description,
286 Background: params.RunInBackground,
287 WorkingDirectory: bgShell.WorkingDir,
288 }
289 if stdout == "" {
290 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
291 }
292 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
293 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
294 }
295
296 // Still running after fast-failure check - return as background job
297 metadata := BashResponseMetadata{
298 StartTime: startTime.UnixMilli(),
299 EndTime: time.Now().UnixMilli(),
300 Description: params.Description,
301 WorkingDirectory: bgShell.WorkingDir,
302 Background: true,
303 ShellID: bgShell.ID,
304 }
305 response := fmt.Sprintf("Background shell started with ID: %s\n\nUse job_output tool to view output or job_kill to terminate.", bgShell.ID)
306 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
307 }
308
309 // Start synchronous execution with auto-background support
310 startTime := time.Now()
311
312 // Start with detached context so it can survive if moved to background
313 bgManager := shell.GetBackgroundShellManager()
314 bgManager.Cleanup()
315 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, blockFuncs(defaultBannedCommands), params.Command, params.Description)
316 if err != nil {
317 return fantasy.ToolResponse{}, fmt.Errorf("error starting shell: %w", err)
318 }
319
320 // Wait for either completion, auto-background threshold, or context cancellation
321 ticker := time.NewTicker(100 * time.Millisecond)
322 defer ticker.Stop()
323 timeout := time.After(AutoBackgroundThreshold)
324
325 var stdout, stderr string
326 var done bool
327 var execErr error
328
329 waitLoop:
330 for {
331 select {
332 case <-ticker.C:
333 stdout, stderr, done, execErr = bgShell.GetOutput()
334 if done {
335 break waitLoop
336 }
337 case <-timeout:
338 stdout, stderr, done, execErr = bgShell.GetOutput()
339 break waitLoop
340 case <-ctx.Done():
341 // Incoming context was cancelled before we moved to background
342 // Kill the shell and return error
343 bgManager.Kill(bgShell.ID)
344 return fantasy.ToolResponse{}, ctx.Err()
345 }
346 }
347
348 if done {
349 // Command completed within threshold - return synchronously
350 // Remove from background manager since we're returning directly
351 // Don't call Kill() as it cancels the context and corrupts the exit code
352 bgManager.Remove(bgShell.ID)
353
354 interrupted := shell.IsInterrupt(execErr)
355 exitCode := shell.ExitCode(execErr)
356 if exitCode == 0 && !interrupted && execErr != nil {
357 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
358 }
359
360 stdout = formatOutput(stdout, stderr, execErr)
361
362 metadata := BashResponseMetadata{
363 StartTime: startTime.UnixMilli(),
364 EndTime: time.Now().UnixMilli(),
365 Output: stdout,
366 Description: params.Description,
367 Background: params.RunInBackground,
368 WorkingDirectory: bgShell.WorkingDir,
369 }
370 if stdout == "" {
371 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
372 }
373 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
374 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
375 }
376
377 // Still running - keep as background job
378 metadata := BashResponseMetadata{
379 StartTime: startTime.UnixMilli(),
380 EndTime: time.Now().UnixMilli(),
381 Description: params.Description,
382 WorkingDirectory: bgShell.WorkingDir,
383 Background: true,
384 ShellID: bgShell.ID,
385 }
386 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)
387 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
388 })
389}
390
391// formatOutput formats the output of a completed command with error handling
392func formatOutput(stdout, stderr string, execErr error) string {
393 interrupted := shell.IsInterrupt(execErr)
394 exitCode := shell.ExitCode(execErr)
395
396 stdout = truncateOutput(stdout)
397 stderr = truncateOutput(stderr)
398
399 errorMessage := stderr
400 if errorMessage == "" && execErr != nil {
401 errorMessage = execErr.Error()
402 }
403
404 if interrupted {
405 if errorMessage != "" {
406 errorMessage += "\n"
407 }
408 errorMessage += "Command was aborted before completion"
409 } else if exitCode != 0 {
410 if errorMessage != "" {
411 errorMessage += "\n"
412 }
413 errorMessage += fmt.Sprintf("Exit code %d", exitCode)
414 }
415
416 hasBothOutputs := stdout != "" && stderr != ""
417
418 if hasBothOutputs {
419 stdout += "\n"
420 }
421
422 if errorMessage != "" {
423 stdout += "\n" + errorMessage
424 }
425
426 return stdout
427}
428
429func truncateOutput(content string) string {
430 if len(content) <= MaxOutputLength {
431 return content
432 }
433
434 halfLength := MaxOutputLength / 2
435 start := content[:halfLength]
436 end := content[len(content)-halfLength:]
437
438 truncatedLinesCount := countLines(content[halfLength : len(content)-halfLength])
439 return fmt.Sprintf("%s\n\n... [%d lines truncated] ...\n\n%s", start, truncatedLinesCount, end)
440}
441
442func countLines(s string) int {
443 if s == "" {
444 return 0
445 }
446 return len(strings.Split(s, "\n"))
447}
448
449func normalizeWorkingDir(path string) string {
450 if runtime.GOOS == "windows" {
451 cwd, err := os.Getwd()
452 if err != nil {
453 cwd = "C:"
454 }
455 path = strings.ReplaceAll(path, filepath.VolumeName(cwd), "")
456 }
457
458 return filepath.ToSlash(path)
459}