1package tools
2
3import (
4 "context"
5 "encoding/json"
6 "fmt"
7 "strings"
8 "time"
9
10 "github.com/charmbracelet/crush/internal/config"
11 "github.com/charmbracelet/crush/internal/llm/tools/shell"
12 "github.com/charmbracelet/crush/internal/permission"
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}
32
33const (
34 BashToolName = "bash"
35
36 DefaultTimeout = 1 * 60 * 1000 // 1 minutes in milliseconds
37 MaxTimeout = 10 * 60 * 1000 // 10 minutes in milliseconds
38 MaxOutputLength = 30000
39 BashNoOutput = "no output"
40)
41
42var bannedCommands = []string{
43 "alias", "curl", "curlie", "wget", "axel", "aria2c",
44 "nc", "telnet", "lynx", "w3m", "links", "httpie", "xh",
45 "http-prompt", "chrome", "firefox", "safari",
46}
47
48var safeReadOnlyCommands = []string{
49 "ls", "echo", "pwd", "date", "cal", "uptime", "whoami", "id", "groups", "env", "printenv", "set", "unset", "which", "type", "whereis",
50 "whatis", "uname", "hostname", "df", "du", "free", "top", "ps", "kill", "killall", "nice", "nohup", "time", "timeout",
51
52 "git status", "git log", "git diff", "git show", "git branch", "git tag", "git remote", "git ls-files", "git ls-remote",
53 "git rev-parse", "git config --get", "git config --list", "git describe", "git blame", "git grep", "git shortlog",
54
55 "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",
56}
57
58func bashDescription() string {
59 bannedCommandsStr := strings.Join(bannedCommands, ", ")
60 return fmt.Sprintf(`Executes a given bash command in a persistent shell session with optional timeout, ensuring proper handling and security measures.
61
62Before executing the command, please follow these steps:
63
641. Directory Verification:
65 - 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
66 - For example, before running "mkdir foo/bar", first use LS to check that "foo" exists and is the intended parent directory
67
682. Security Check:
69 - 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.
70 - Verify that the command is not one of the banned commands: %s.
71
723. Command Execution:
73 - After ensuring proper quoting, execute the command.
74 - Capture the output of the command.
75
764. Output Processing:
77 - If the output exceeds %d characters, output will be truncated before being returned to you.
78 - Prepare the output for display to the user.
79
805. Return Result:
81 - Provide the processed output of the command.
82 - If any errors occurred during execution, include those in the output.
83
84Usage notes:
85- The command argument is required.
86- You can specify an optional timeout in milliseconds (up to 600000ms / 10 minutes). If not specified, commands will timeout after 30 minutes.
87- 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.
88- When issuing multiple commands, use the ';' or '&&' operator to separate them. DO NOT use newlines (newlines are ok in quoted strings).
89- 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.
90- 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.
91<good-example>
92pytest /foo/bar/tests
93</good-example>
94<bad-example>
95cd /foo/bar && pytest tests
96</bad-example>
97
98# Committing changes with git
99
100When the user asks you to create a new git commit, follow these steps carefully:
101
1021. 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!):
103 - Run a git status command to see all untracked files.
104 - Run a git diff command to see both staged and unstaged changes that will be committed.
105 - Run a git log command to see recent commit messages, so that you can follow this repository's commit message style.
106
1072. 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.
108
1093. Analyze all staged changes (both previously staged and newly added) and draft a commit message. Wrap your analysis process in <commit_analysis> tags:
110
111<commit_analysis>
112- List the files that have been changed or added
113- Summarize the nature of the changes (eg. new feature, enhancement to an existing feature, bug fix, refactoring, test, docs, etc.)
114- Brainstorm the purpose or motivation behind these changes
115- Do not use tools to explore code, beyond what is available in the git context
116- Assess the impact of these changes on the overall project
117- Check for any sensitive information that shouldn't be committed
118- Draft a concise (1-2 sentences) commit message that focuses on the "why" rather than the "what"
119- Ensure your language is clear, concise, and to the point
120- 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.)
121- Ensure the message is not generic (avoid words like "Update" or "Fix" without context)
122- Review the draft message to ensure it accurately reflects the changes and their purpose
123</commit_analysis>
124
1254. Create the commit with a message ending with:
126💘 Generated with Crush
127Co-Authored-By: Crush <noreply@crush.charm.land>
128
129- In order to ensure good formatting, ALWAYS pass the commit message via a HEREDOC, a la this example:
130<example>
131git commit -m "$(cat <<'EOF'
132 Commit message here.
133
134 💘 Generated with Crush
135 Co-Authored-By: 💘 Crush <noreply@crush.charm.land>
136 EOF
137 )"
138</example>
139
1405. 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.
141
1426. Finally, run git status to make sure the commit succeeded.
143
144Important notes:
145- When possible, combine the "git add" and "git commit" commands into a single "git commit -am" command, to speed things up
146- 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.
147- NEVER update the git config
148- DO NOT push to the remote repository
149- 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.
150- If there are no changes to commit (i.e., no untracked files and no modifications), do not create an empty commit
151- Ensure your commit message is meaningful and concise. It should explain the purpose of the changes, not just describe them.
152- Return an empty response - the user will see the git output directly
153
154# Creating pull requests
155Use 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.
156
157IMPORTANT: When the user asks you to create a pull request, follow these steps carefully:
158
1591. 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!):
160 - Run a git status command to see all untracked files.
161 - Run a git diff command to see both staged and unstaged changes that will be committed.
162 - 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
163 - 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.)
164
1652. Create new branch if needed
166
1673. Commit changes if needed
168
1694. Push to remote with -u flag if needed
170
1715. 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:
172
173<pr_analysis>
174- List the commits since diverging from the main branch
175- Summarize the nature of the changes (eg. new feature, enhancement to an existing feature, bug fix, refactoring, test, docs, etc.)
176- Brainstorm the purpose or motivation behind these changes
177- Assess the impact of these changes on the overall project
178- Do not use tools to explore code, beyond what is available in the git context
179- Check for any sensitive information that shouldn't be committed
180- Draft a concise (1-2 bullet points) pull request summary that focuses on the "why" rather than the "what"
181- Ensure the summary accurately reflects all changes since diverging from the main branch
182- Ensure your language is clear, concise, and to the point
183- 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.)
184- Ensure the summary is not generic (avoid words like "Update" or "Fix" without context)
185- Review the draft summary to ensure it accurately reflects the changes and their purpose
186</pr_analysis>
187
1886. Create PR using gh pr create with the format below. Use a HEREDOC to pass the body to ensure correct formatting.
189<example>
190gh pr create --title "the pr title" --body "$(cat <<'EOF'
191## Summary
192<1-3 bullet points>
193
194## Test plan
195[Checklist of TODOs for testing the pull request...]
196
197💘 Generated with Crush
198EOF
199)"
200</example>
201
202Important:
203- Return an empty response - the user will see the gh output directly
204- Never update git config`, bannedCommandsStr, MaxOutputLength)
205}
206
207func NewBashTool(permission permission.Service) BaseTool {
208 return &bashTool{
209 permissions: permission,
210 }
211}
212
213func (b *bashTool) Info() ToolInfo {
214 return ToolInfo{
215 Name: BashToolName,
216 Description: bashDescription(),
217 Parameters: map[string]any{
218 "command": map[string]any{
219 "type": "string",
220 "description": "The command to execute",
221 },
222 "timeout": map[string]any{
223 "type": "number",
224 "description": "Optional timeout in milliseconds (max 600000)",
225 },
226 },
227 Required: []string{"command"},
228 }
229}
230
231func (b *bashTool) Run(ctx context.Context, call ToolCall) (ToolResponse, error) {
232 var params BashParams
233 if err := json.Unmarshal([]byte(call.Input), ¶ms); err != nil {
234 return NewTextErrorResponse("invalid parameters"), nil
235 }
236
237 if params.Timeout > MaxTimeout {
238 params.Timeout = MaxTimeout
239 } else if params.Timeout <= 0 {
240 params.Timeout = DefaultTimeout
241 }
242
243 if params.Command == "" {
244 return NewTextErrorResponse("missing command"), nil
245 }
246
247 baseCmd := strings.Fields(params.Command)[0]
248 for _, banned := range bannedCommands {
249 if strings.EqualFold(baseCmd, banned) {
250 return NewTextErrorResponse(fmt.Sprintf("command '%s' is not allowed", baseCmd)), nil
251 }
252 }
253
254 isSafeReadOnly := false
255 cmdLower := strings.ToLower(params.Command)
256
257 for _, safe := range safeReadOnlyCommands {
258 if strings.HasPrefix(cmdLower, strings.ToLower(safe)) {
259 if len(cmdLower) == len(safe) || cmdLower[len(safe)] == ' ' || cmdLower[len(safe)] == '-' {
260 isSafeReadOnly = true
261 break
262 }
263 }
264 }
265
266 sessionID, messageID := GetContextValues(ctx)
267 if sessionID == "" || messageID == "" {
268 return ToolResponse{}, fmt.Errorf("session ID and message ID are required for creating a new file")
269 }
270 if !isSafeReadOnly {
271 p := b.permissions.Request(
272 permission.CreatePermissionRequest{
273 SessionID: sessionID,
274 Path: config.WorkingDirectory(),
275 ToolName: BashToolName,
276 Action: "execute",
277 Description: fmt.Sprintf("Execute command: %s", params.Command),
278 Params: BashPermissionsParams{
279 Command: params.Command,
280 },
281 },
282 )
283 if !p {
284 return ToolResponse{}, permission.ErrorPermissionDenied
285 }
286 }
287 startTime := time.Now()
288 shell := shell.GetPersistentShell(config.WorkingDirectory())
289 stdout, stderr, exitCode, interrupted, err := shell.Exec(ctx, params.Command, params.Timeout)
290 if err != nil {
291 return ToolResponse{}, fmt.Errorf("error executing command: %w", err)
292 }
293
294 stdout = truncateOutput(stdout)
295 stderr = truncateOutput(stderr)
296
297 errorMessage := stderr
298 if interrupted {
299 if errorMessage != "" {
300 errorMessage += "\n"
301 }
302 errorMessage += "Command was aborted before completion"
303 } else if exitCode != 0 {
304 if errorMessage != "" {
305 errorMessage += "\n"
306 }
307 errorMessage += fmt.Sprintf("Exit code %d", exitCode)
308 }
309
310 hasBothOutputs := stdout != "" && stderr != ""
311
312 if hasBothOutputs {
313 stdout += "\n"
314 }
315
316 if errorMessage != "" {
317 stdout += "\n" + errorMessage
318 }
319
320 metadata := BashResponseMetadata{
321 StartTime: startTime.UnixMilli(),
322 EndTime: time.Now().UnixMilli(),
323 }
324 if stdout == "" {
325 return WithResponseMetadata(NewTextResponse(BashNoOutput), metadata), nil
326 }
327 return WithResponseMetadata(NewTextResponse(stdout), metadata), nil
328}
329
330func truncateOutput(content string) string {
331 if len(content) <= MaxOutputLength {
332 return content
333 }
334
335 halfLength := MaxOutputLength / 2
336 start := content[:halfLength]
337 end := content[len(content)-halfLength:]
338
339 truncatedLinesCount := countLines(content[halfLength : len(content)-halfLength])
340 return fmt.Sprintf("%s\n\n... [%d lines truncated] ...\n\n%s", start, truncatedLinesCount, end)
341}
342
343func countLines(s string) int {
344 if s == "" {
345 return 0
346 }
347 return len(strings.Split(s, "\n"))
348}