1package tools
2
3import (
4 "context"
5 "encoding/json"
6 "fmt"
7 "runtime"
8 "strings"
9 "time"
10
11 "github.com/charmbracelet/crush/internal/permission"
12 "github.com/charmbracelet/crush/internal/shell"
13)
14
15type BashParams struct {
16 Command string `json:"command"`
17 Timeout int `json:"timeout"`
18}
19
20type BashPermissionsParams struct {
21 Command string `json:"command"`
22 Timeout int `json:"timeout"`
23}
24
25type BashResponseMetadata struct {
26 StartTime int64 `json:"start_time"`
27 EndTime int64 `json:"end_time"`
28}
29type bashTool struct {
30 permissions permission.Service
31 workingDir string
32}
33
34const (
35 BashToolName = "bash"
36
37 DefaultTimeout = 1 * 60 * 1000 // 1 minutes in milliseconds
38 MaxTimeout = 10 * 60 * 1000 // 10 minutes in milliseconds
39 MaxOutputLength = 30000
40 BashNoOutput = "no output"
41)
42
43var bannedCommands = []string{
44 "alias", "curl", "curlie", "wget", "axel", "aria2c",
45 "nc", "telnet", "lynx", "w3m", "links", "httpie", "xh",
46 "http-prompt", "chrome", "firefox", "safari",
47}
48
49// getSafeReadOnlyCommands returns platform-appropriate safe commands
50func getSafeReadOnlyCommands() []string {
51 // Base commands that work on all platforms
52 baseCommands := []string{
53 // Cross-platform commands
54 "echo", "hostname", "whoami",
55
56 // Git commands (cross-platform)
57 "git status", "git log", "git diff", "git show", "git branch", "git tag", "git remote", "git ls-files", "git ls-remote",
58 "git rev-parse", "git config --get", "git config --list", "git describe", "git blame", "git grep", "git shortlog",
59
60 // Go commands (cross-platform)
61 "go version", "go help", "go list", "go env", "go doc", "go vet", "go fmt", "go mod", "go test", "go build", "go run", "go install", "go clean",
62 }
63
64 if runtime.GOOS == "windows" {
65 // Windows-specific commands
66 windowsCommands := []string{
67 "dir", "type", "where", "ver", "systeminfo", "tasklist", "ipconfig", "ping", "nslookup",
68 "Get-Process", "Get-Location", "Get-ChildItem", "Get-Content", "Get-Date", "Get-Host", "Get-ComputerInfo",
69 }
70 return append(baseCommands, windowsCommands...)
71 } else {
72 // Unix/Linux commands (including WSL, since WSL reports as Linux)
73 unixCommands := []string{
74 "ls", "pwd", "date", "cal", "uptime", "id", "groups", "env", "printenv", "set", "unset", "which", "type", "whereis",
75 "whatis", "uname", "df", "du", "free", "top", "ps", "kill", "killall", "nice", "nohup", "time", "timeout",
76 }
77 return append(baseCommands, unixCommands...)
78 }
79}
80
81func bashDescription() string {
82 bannedCommandsStr := strings.Join(bannedCommands, ", ")
83 return fmt.Sprintf(`Executes a given bash command in a persistent shell session with optional timeout, ensuring proper handling and security measures.
84
85CROSS-PLATFORM SHELL SUPPORT:
86- Unix/Linux/macOS: Uses native bash/sh shell
87- Windows: Intelligent shell selection:
88 * Windows commands (dir, type, copy, etc.) use cmd.exe
89 * PowerShell commands (Get-, Set-, etc.) use PowerShell
90 * Unix-style commands (ls, cat, etc.) use POSIX emulation
91- WSL: Automatically treated as Linux (which is correct)
92- Automatic detection: Chooses the best shell based on command and platform
93- Persistent state: Working directory and environment variables persist between commands
94
95WINDOWS-SPECIFIC FEATURES:
96- Native Windows commands: dir, type, copy, move, del, md, rd, cls, where, tasklist, etc.
97- PowerShell support: Get-Process, Set-Location, and other PowerShell cmdlets
98- Windows path handling: Supports both forward slashes (/) and backslashes (\)
99- Drive letters: Properly handles C:\, D:\, etc.
100- Environment variables: Supports both Unix ($VAR) and Windows (%%VAR%%) syntax
101
102Before executing the command, please follow these steps:
103
1041. Directory Verification:
105 - If the command will create new directories or files, first use the LS tool to verify the parent directory exists and is the correct location
106 - For example, before running "mkdir foo/bar", first use LS to check that "foo" exists and is the intended parent directory
107
1082. Security Check:
109 - For security and to limit the threat of a prompt injection attack, some commands are limited or banned. If you use a disallowed command, you will receive an error message explaining the restriction. Explain the error to the User.
110 - Verify that the command is not one of the banned commands: %s.
111
1123. Command Execution:
113 - After ensuring proper quoting, execute the command.
114 - Capture the output of the command.
115
1164. Output Processing:
117 - If the output exceeds %d characters, output will be truncated before being returned to you.
118 - Prepare the output for display to the user.
119
1205. Return Result:
121 - Provide the processed output of the command.
122 - If any errors occurred during execution, include those in the output.
123
124Usage notes:
125- The command argument is required.
126- You can specify an optional timeout in milliseconds (up to 600000ms / 10 minutes). If not specified, commands will timeout after 30 minutes.
127- VERY IMPORTANT: You MUST avoid using search commands like 'find' and 'grep'. Instead use Grep, Glob, or Agent tools to search. You MUST avoid read tools like 'cat', 'head', 'tail', and 'ls', and use FileRead and LS tools to read files.
128- When issuing multiple commands, use the ';' or '&&' operator to separate them. DO NOT use newlines (newlines are ok in quoted strings).
129- IMPORTANT: All commands share the same shell session. Shell state (environment variables, virtual environments, current directory, etc.) persist between commands. For example, if you set an environment variable as part of a command, the environment variable will persist for subsequent commands.
130- Try to maintain your current working directory throughout the session by using absolute paths and avoiding usage of 'cd'. You may use 'cd' if the User explicitly requests it.
131<good-example>
132pytest /foo/bar/tests
133</good-example>
134<bad-example>
135cd /foo/bar && pytest tests
136</bad-example>
137
138# Committing changes with git
139
140When the user asks you to create a new git commit, follow these steps carefully:
141
1421. Start with a single message that contains exactly three tool_use blocks that do the following (it is VERY IMPORTANT that you send these tool_use blocks in a single message, otherwise it will feel slow to the user!):
143 - Run a git status command to see all untracked files.
144 - Run a git diff command to see both staged and unstaged changes that will be committed.
145 - Run a git log command to see recent commit messages, so that you can follow this repository's commit message style.
146
1472. Use the git context at the start of this conversation to determine which files are relevant to your commit. Add relevant untracked files to the staging area. Do not commit files that were already modified at the start of this conversation, if they are not relevant to your commit.
148
1493. Analyze all staged changes (both previously staged and newly added) and draft a commit message. Wrap your analysis process in <commit_analysis> tags:
150
151<commit_analysis>
152- List the files that have been changed or added
153- Summarize the nature of the changes (eg. new feature, enhancement to an existing feature, bug fix, refactoring, test, docs, etc.)
154- Brainstorm the purpose or motivation behind these changes
155- Do not use tools to explore code, beyond what is available in the git context
156- Assess the impact of these changes on the overall project
157- Check for any sensitive information that shouldn't be committed
158- Draft a concise (1-2 sentences) commit message that focuses on the "why" rather than the "what"
159- Ensure your language is clear, concise, and to the point
160- Ensure the message accurately reflects the changes and their purpose (i.e. "add" means a wholly new feature, "update" means an enhancement to an existing feature, "fix" means a bug fix, etc.)
161- Ensure the message is not generic (avoid words like "Update" or "Fix" without context)
162- Review the draft message to ensure it accurately reflects the changes and their purpose
163</commit_analysis>
164
1654. Create the commit with a message ending with:
166💘 Generated with Crush
167Co-Authored-By: Crush <noreply@crush.charm.land>
168
169- In order to ensure good formatting, ALWAYS pass the commit message via a HEREDOC, a la this example:
170<example>
171git commit -m "$(cat <<'EOF'
172 Commit message here.
173
174 💘 Generated with Crush
175 Co-Authored-By: 💘 Crush <noreply@crush.charm.land>
176 EOF
177 )"
178</example>
179
1805. If the commit fails due to pre-commit hook changes, retry the commit ONCE to include these automated changes. If it fails again, it usually means a pre-commit hook is preventing the commit. If the commit succeeds but you notice that files were modified by the pre-commit hook, you MUST amend your commit to include them.
181
1826. Finally, run git status to make sure the commit succeeded.
183
184Important notes:
185- When possible, combine the "git add" and "git commit" commands into a single "git commit -am" command, to speed things up
186- However, be careful not to stage files (e.g. with 'git add .') for commits that aren't part of the change, they may have untracked files they want to keep around, but not commit.
187- NEVER update the git config
188- DO NOT push to the remote repository
189- IMPORTANT: Never use git commands with the -i flag (like git rebase -i or git add -i) since they require interactive input which is not supported.
190- If there are no changes to commit (i.e., no untracked files and no modifications), do not create an empty commit
191- Ensure your commit message is meaningful and concise. It should explain the purpose of the changes, not just describe them.
192- Return an empty response - the user will see the git output directly
193
194# Creating pull requests
195Use the gh command via the Bash tool for ALL GitHub-related tasks including working with issues, pull requests, checks, and releases. If given a Github URL use the gh command to get the information needed.
196
197IMPORTANT: When the user asks you to create a pull request, follow these steps carefully:
198
1991. Understand the current state of the branch. Remember to send a single message that contains multiple tool_use blocks (it is VERY IMPORTANT that you do this in a single message, otherwise it will feel slow to the user!):
200 - Run a git status command to see all untracked files.
201 - Run a git diff command to see both staged and unstaged changes that will be committed.
202 - Check if the current branch tracks a remote branch and is up to date with the remote, so you know if you need to push to the remote
203 - Run a git log command and 'git diff main...HEAD' to understand the full commit history for the current branch (from the time it diverged from the 'main' branch.)
204
2052. Create new branch if needed
206
2073. Commit changes if needed
208
2094. Push to remote with -u flag if needed
210
2115. Analyze all changes that will be included in the pull request, making sure to look at all relevant commits (not just the latest commit, but all commits that will be included in the pull request!), and draft a pull request summary. Wrap your analysis process in <pr_analysis> tags:
212
213<pr_analysis>
214- List the commits since diverging from the main branch
215- Summarize the nature of the changes (eg. new feature, enhancement to an existing feature, bug fix, refactoring, test, docs, etc.)
216- Brainstorm the purpose or motivation behind these changes
217- Assess the impact of these changes on the overall project
218- Do not use tools to explore code, beyond what is available in the git context
219- Check for any sensitive information that shouldn't be committed
220- Draft a concise (1-2 bullet points) pull request summary that focuses on the "why" rather than the "what"
221- Ensure the summary accurately reflects all changes since diverging from the main branch
222- Ensure your language is clear, concise, and to the point
223- Ensure the summary accurately reflects the changes and their purpose (ie. "add" means a wholly new feature, "update" means an enhancement to an existing feature, "fix" means a bug fix, etc.)
224- Ensure the summary is not generic (avoid words like "Update" or "Fix" without context)
225- Review the draft summary to ensure it accurately reflects the changes and their purpose
226</pr_analysis>
227
2286. Create PR using gh pr create with the format below. Use a HEREDOC to pass the body to ensure correct formatting.
229<example>
230gh pr create --title "the pr title" --body "$(cat <<'EOF'
231## Summary
232<1-3 bullet points>
233
234## Test plan
235[Checklist of TODOs for testing the pull request...]
236
237💘 Generated with Crush
238EOF
239)"
240</example>
241
242Important:
243- Return an empty response - the user will see the gh output directly
244- Never update git config`, bannedCommandsStr, MaxOutputLength)
245}
246
247func NewBashTool(permission permission.Service, workingDir string) BaseTool {
248 return &bashTool{
249 permissions: permission,
250 workingDir: workingDir,
251 }
252}
253
254func (b *bashTool) Name() string {
255 return BashToolName
256}
257
258func (b *bashTool) Info() ToolInfo {
259 return ToolInfo{
260 Name: BashToolName,
261 Description: bashDescription(),
262 Parameters: map[string]any{
263 "command": map[string]any{
264 "type": "string",
265 "description": "The command to execute",
266 },
267 "timeout": map[string]any{
268 "type": "number",
269 "description": "Optional timeout in milliseconds (max 600000)",
270 },
271 },
272 Required: []string{"command"},
273 }
274}
275
276func (b *bashTool) Run(ctx context.Context, call ToolCall) (ToolResponse, error) {
277 var params BashParams
278 if err := json.Unmarshal([]byte(call.Input), ¶ms); err != nil {
279 return NewTextErrorResponse("invalid parameters"), nil
280 }
281
282 if params.Timeout > MaxTimeout {
283 params.Timeout = MaxTimeout
284 } else if params.Timeout <= 0 {
285 params.Timeout = DefaultTimeout
286 }
287
288 if params.Command == "" {
289 return NewTextErrorResponse("missing command"), nil
290 }
291
292 baseCmd := strings.Fields(params.Command)[0]
293 for _, banned := range bannedCommands {
294 if strings.EqualFold(baseCmd, banned) {
295 return NewTextErrorResponse(fmt.Sprintf("command '%s' is not allowed", baseCmd)), nil
296 }
297 }
298
299 isSafeReadOnly := false
300 cmdLower := strings.ToLower(params.Command)
301
302 // Get platform-appropriate safe commands
303 safeReadOnlyCommands := getSafeReadOnlyCommands()
304 for _, safe := range safeReadOnlyCommands {
305 if strings.HasPrefix(cmdLower, strings.ToLower(safe)) {
306 if len(cmdLower) == len(safe) || cmdLower[len(safe)] == ' ' || cmdLower[len(safe)] == '-' {
307 isSafeReadOnly = true
308 break
309 }
310 }
311 }
312
313 sessionID, messageID := GetContextValues(ctx)
314 if sessionID == "" || messageID == "" {
315 return ToolResponse{}, fmt.Errorf("session ID and message ID are required for creating a new file")
316 }
317 if !isSafeReadOnly {
318 p := b.permissions.Request(
319 permission.CreatePermissionRequest{
320 SessionID: sessionID,
321 Path: b.workingDir,
322 ToolName: BashToolName,
323 Action: "execute",
324 Description: fmt.Sprintf("Execute command: %s", params.Command),
325 Params: BashPermissionsParams{
326 Command: params.Command,
327 },
328 },
329 )
330 if !p {
331 return ToolResponse{}, permission.ErrorPermissionDenied
332 }
333 }
334 startTime := time.Now()
335 if params.Timeout > 0 {
336 var cancel context.CancelFunc
337 ctx, cancel = context.WithTimeout(ctx, time.Duration(params.Timeout)*time.Millisecond)
338 defer cancel()
339 }
340 stdout, stderr, err := shell.
341 GetPersistentShell(b.workingDir).
342 Exec(ctx, params.Command)
343 interrupted := shell.IsInterrupt(err)
344 exitCode := shell.ExitCode(err)
345 if exitCode == 0 && !interrupted && err != nil {
346 return ToolResponse{}, fmt.Errorf("error executing command: %w", err)
347 }
348
349 stdout = truncateOutput(stdout)
350 stderr = truncateOutput(stderr)
351
352 errorMessage := stderr
353 if interrupted {
354 if errorMessage != "" {
355 errorMessage += "\n"
356 }
357 errorMessage += "Command was aborted before completion"
358 } else if exitCode != 0 {
359 if errorMessage != "" {
360 errorMessage += "\n"
361 }
362 errorMessage += fmt.Sprintf("Exit code %d", exitCode)
363 }
364
365 hasBothOutputs := stdout != "" && stderr != ""
366
367 if hasBothOutputs {
368 stdout += "\n"
369 }
370
371 if errorMessage != "" {
372 stdout += "\n" + errorMessage
373 }
374
375 metadata := BashResponseMetadata{
376 StartTime: startTime.UnixMilli(),
377 EndTime: time.Now().UnixMilli(),
378 }
379 if stdout == "" {
380 return WithResponseMetadata(NewTextResponse(BashNoOutput), metadata), nil
381 }
382 return WithResponseMetadata(NewTextResponse(stdout), metadata), nil
383}
384
385func truncateOutput(content string) string {
386 if len(content) <= MaxOutputLength {
387 return content
388 }
389
390 halfLength := MaxOutputLength / 2
391 start := content[:halfLength]
392 end := content[len(content)-halfLength:]
393
394 truncatedLinesCount := countLines(content[halfLength : len(content)-halfLength])
395 return fmt.Sprintf("%s\n\n... [%d lines truncated] ...\n\n%s", start, truncatedLinesCount, end)
396}
397
398func countLines(s string) int {
399 if s == "" {
400 return 0
401 }
402 return len(strings.Split(s, "\n"))
403}