vibe

Mistral Vibe CLI Delegation Skill

Delegate simple, well-defined coding tasks to Mistral's Vibe CLI agent (powered by Devstral 2.1) to save Claude tokens for harder problems. Vibe runs non-interactively via --prompt and returns results that Claude summarizes for the user.

Prerequisites

• vibe CLI installed and on PATH (install: curl -LsSf https://mistral.ai/vibe/install.sh | bash)
• Mistral API key configured (~/.vibe/.env or MISTRAL_API_KEY env var)
• Confirm installation: vibe --version; resolve any errors before using this skill

If vibe is not installed or not configured, inform the user and provide the installation instructions above. Do NOT attempt to run vibe commands if the prerequisites are not met.

How It Works

1. Claude evaluates the user's request
2. If the task is simple/mechanical, Claude delegates to Vibe via a shell command
3. Vibe runs non-interactively with --prompt, auto-approving tool executions
4. Claude reads the output and summarizes results back to the user
5. If Vibe's output is insufficient or incorrect, Claude can either retry with a refined prompt or fall back to handling the task itself

Task Routing Guidelines

Delegate to Vibe (cheap, fast)

• Boilerplate generation (new files, structs, interfaces, CRUD endpoints)
• Simple refactors (rename, extract function, move code between files)
• Test scaffolding and simple test writing
• Documentation and comment generation
• Formatting, linting fixes, import sorting
• Dependency version bumps
• Mechanical find-and-replace across files
• Adding error handling to straightforward functions
• Generating type definitions or interfaces from existing code
• Simple bug fixes where the issue is clearly identified

Keep in Claude (complex, nuanced)

• Architectural decisions or design pattern selection
• Security-sensitive code review or vulnerability analysis
• Complex multi-step debugging requiring deep reasoning
• Performance optimization requiring profiling analysis
• Tasks requiring understanding of the full project context across many files
• Anything the user explicitly wants Claude to handle

When in doubt

Ask the user: "This looks like it could be delegated to Vibe (Devstral 2.1) to save tokens. Want me to handle it myself or delegate?"

CLI Usage

Basic non-interactive execution

vibe --prompt "<task description>" --max-turns <N> --max-price <dollars> 2>/dev/null

Flags reference

Flag	Description	Default in --prompt mode
--prompt "<task>"	Run non-interactively with this prompt	Required
--max-turns N	Limit assistant turns	No limit
--max-price N	Cost cap in USD	No limit
--enabled-tools TOOL	Restrict to specific tools (can repeat)	All tools enabled

Important notes

• --prompt mode automatically enables auto-approve (no user confirmation needed)
• Stderr contains thinking tokens / debug output — suppress with 2>/dev/null to avoid bloating Claude Code's context window
• If the user explicitly asks to see Vibe's thinking/reasoning, omit the 2>/dev/null
• Vibe requires a trusted folder — run from the project's working directory

Execution Patterns

Pattern 1: Simple task delegation (most common)

For a contained, single-purpose task:

cd /path/to/project && vibe --prompt "Add JSDoc comments to all exported functions in src/utils.ts" --max-turns 10 --max-price 0.50 2>/dev/null

Pattern 2: Read-only analysis

For tasks that only need to read code (no writes):

cd /path/to/project && vibe --prompt "List all API endpoints in this project with their HTTP methods and paths" --enabled-tools read_file --enabled-tools grep --max-turns 8 --max-price 0.30 2>/dev/null

Pattern 3: Scoped file edits

For edits limited to specific files:

cd /path/to/project && vibe --prompt "Refactor the error handling in src/api/client.rs to use thiserror instead of manual impl. Only modify files in src/api/." --max-turns 15 --max-price 1.00 2>/dev/null

Pattern 4: Test generation

cd /path/to/project && vibe --prompt "Generate unit tests for the functions in src/auth/token.go. Use the standard testing package. Place tests in src/auth/token_test.go" --max-turns 12 --max-price 0.50 2>/dev/null

Prompt Engineering for Vibe

When constructing the --prompt string for Vibe, follow these guidelines:

1. Be specific and self-contained — Vibe does not have the conversation context that Claude has. Include all relevant details: file paths, function names, expected behavior, constraints.

2. Specify scope explicitly — Tell Vibe which files/directories to work in and which to avoid.

3. State the expected output — "Create a new file at X", "Modify function Y in file Z", "Print a summary to stdout".

4. Include language/framework context — "This is a Rust project using Actix-web", "This is a SvelteKit app with TypeScript".

5. Set boundaries — "Do not modify any files outside src/api/", "Do not add new dependencies".

Handling Vibe Output

After Vibe completes:

1. Read the stdout output — This contains Vibe's actions and results
2. Verify the changes — Check modified files if needed (use git diff or read the files)
3. Summarize for the user — Tell them what Vibe did, what files changed, and whether the task completed successfully
4. Handle failures gracefully — If Vibe failed or produced incorrect results:
   • For minor issues: retry with a more specific prompt
   • For fundamental failures: fall back to handling the task directly with Claude
   • Always inform the user what happened

Cost Management

Devstral 2.1 pricing: $0.40/M input tokens, $2.00/M output tokens. For simple tasks, set conservative limits:

Task type	Suggested --max-turns	Suggested --max-price
Boilerplate / scaffolding	8-10	$0.30
Simple refactor	10-15	$0.50
Test generation	10-15	$0.50
Multi-file mechanical change	15-20	$1.00
Read-only analysis	5-8	$0.20

Example Workflow

User says: "Add error handling to the API calls in src/services/"

Claude's process:

1. Recognizes this as a mechanical task suitable for Vibe
2. Constructs a specific prompt with project context
3. Runs:

cd /path/to/project && vibe --prompt "Add proper error handling (try/catch or Result types as appropriate) to all API call functions in the src/services/ directory. Preserve existing function signatures. Use the project's existing error handling patterns." --max-turns 15 --max-price 0.50 2>/dev/null

4. Reads output, verifies changes with git diff --stat
5. Reports to user: "Vibe updated 4 files in src/services/ — added error handling to 12 API calls. Here's a summary of changes: ..."