---

name: sandy description: MCP action building blocks - Replay tool sequences to save tokens. Use for: (1) Full automation when all steps are deterministic, (2) Micro patterns like click-and-wait or scroll-and-wait where Sandy executes actions, then LLM calls screenshot for visual analysis. allowed-tools: Bash, Read, Write, Glob

Sandy - Deterministic MCP Scenario Replay

Sandy replays MCP tool call sequences without LLM inference. When you identify a repeatable workflow, create a scenario to accelerate future executions.

On Invocation

When /sandy is called, immediately analyze the current session:

1. Review tool calls made in this session (both mcp__* and claude__* tools)
2. Identify patterns - Are there repeatable sequences? (e.g., navigate → click → extract, or read → edit → bash)
3. Check for micro-pattern opportunities:
   • If using browser/UI tools (chrome-devtools, computer-use, etc.)
   • And similar actions will likely repeat
   • → Suggest short Sandy sequences (click-screenshot, scroll-screenshot)
4. Check existing scenarios - Search .sandy/scenarios/ for matches
5. Suggest actions:
   • If a reusable pattern exists → Offer to save as scenario
   • If a micro-pattern fits → Suggest hybrid approach (Sandy for actions, LLM for judgment)
   • If a matching scenario exists → Offer to replay it
   • If no patterns found → Explain Sandy's purpose and wait for user direction

Supported tool prefixes:

• mcp__<server>__<tool> - MCP server tools (e.g., mcp__chrome-devtools__click)
• claude__<tool> - Claude Code native tools (see list below)
• sandy__<tool> - Sandy built-in tools (e.g., sandy__wait, sandy__log)

Supported Claude native tools:

Tool	Description
claude__read	Read file contents
claude__write	Write file contents
claude__edit	Edit file with string replacement
claude__glob	Find files by pattern
claude__grep	Search file contents with regex
claude__bash	Execute shell commands
claude__web_fetch	Fetch URL contents
claude__notebook_edit	Edit Jupyter notebooks

Example response:

"I found a repeating pattern in this session: claude__glob → claude__read → claude__edit. Would you like to save this workflow as a scenario?"

Why Sandy

Benefit	Description
Token cost	Zero LLM tokens for replay
Speed	Direct MCP calls, no reasoning overhead
Consistency	Identical execution every time

Usage Patterns

Full Automation (Best Fit)

All steps are deterministic, no intermediate judgment needed.

• Data collection, form filling, batch operations
• CI/CD pipelines, scheduled tasks
• Results saved to file for later review

Hybrid Pattern

Sandy handles actions, LLM handles judgment between sequences.

• Works when judgment points are infrequent
• Less effective if judgment needed after every action

When NOT to Use

• One-time operations
• Immediate visual judgment required after each action (e.g., UI inspection where every screenshot needs analysis)
• Tasks where Sandy→LLM→Sandy switching adds more overhead than direct MCP calls

Key question: Can results be batched for later review, or is immediate judgment needed?

• Batch review possible → Sandy fits well
• Immediate judgment needed → Direct MCP may be simpler

Micro Patterns (Building Blocks)

Short sequences combined with LLM judgment for complex tasks.

Note: Sandy CLI cannot return images visually. Screenshot should be called directly by LLM after Sandy execution.

Pattern	Sandy Steps	Then LLM
click-and-check	click → wait	screenshot (direct call)
scroll-and-check	scroll → wait	screenshot (direct call)
type-submit	fill → click	-
navigate-and-check	navigate → wait	screenshot (direct call)

Micro Pattern example:

{
  "version": "2.1",
  "metadata": { "name": "click-and-wait", "description": "Click then wait for render" },
  "variables": { "UID": "" },
  "steps": [
    { "step": 1, "id": "click", "tool": "mcp__chrome-devtools__click", "params": { "uid": "{{UID}}" } },
    { "step": 2, "id": "wait", "tool": "sandy__wait", "params": { "duration": 0.5 } }
  ]
}

Hybrid workflow:

1. LLM: Analyze page → identify element UID
2. Sandy: Execute `click-and-wait`
3. LLM: Call screenshot directly → visual analysis
4. Repeat...

When to Save a Scenario

Save when any of these apply:

• Same MCP tool sequence used 2+ times
• User mentions "repeat", "daily", "automate"
• Clear workflow pattern emerges (navigate → scrape → save)

Variables to Extract

When saving, parameterize:

Type	Example	Variable
User inputs	Issue title, search terms	{{TITLE}}
Identifiers	Repo name, PR number	{{REPO}}, {{PR_NUMBER}}
URLs	Target pages	{{TARGET_URL}}
Output paths	File destinations	{{OUTPUT_PATH}}

Finding Existing Scenarios

Location: .sandy/scenarios/ (project-local)

Search workflow:

1. Use Glob to find scenarios:

   Glob pattern: .sandy/scenarios/**/*.json
   

2. Read each file and check:

   • metadata.name - Scenario name
   • metadata.description - What it does
   • steps - MCP tool sequence

3. Match against current task requirements

Bundled examples: ${CLAUDE_PLUGIN_ROOT}/assets/examples/

Creating Scenarios

Workflow

1. Execute - Perform the workflow using actual MCP tools
2. Track - Note which tools were called and with what parameters
3. Parameterize - Identify values that should become variables
4. Write - Create scenario JSON based on the executed workflow
5. Save - Write to .sandy/scenarios/<name>.json
6. Verify - Run with --dry-run to validate

Important: Always test the workflow first before writing the scenario.

Minimal Schema

{
  "version": "2.1",
  "metadata": { "name": "...", "description": "..." },
  "variables": { "VAR_NAME": "default" },
  "steps": [
    {
      "step": 1,
      "id": "unique_id",
      "tool": "mcp__server__tool",
      "params": { "key": "{{VAR_NAME}}" },
      "output": { "field": "$.json.path" }
    }
  ]
}

Full schema: See ${CLAUDE_PLUGIN_ROOT}/references/schema.md

Tool Naming

Format: mcp__<server>__<tool_name>

Examples:

• mcp__github__create_issue
• mcp__chrome-devtools__click
• mcp__supabase__query

Executing Scenarios

python3 ${CLAUDE_PLUGIN_ROOT}/scripts/play.py <scenario.json> [options] --json

Options

Option	Description
--start N	Start from step N
--end N	End at step N
--var KEY=VALUE	Set variable (repeatable)
--env FILE	Load variables from .env
--dry-run	Validate without executing
--debug	Enable debug output
--json	Output as JSON

Partial Execution

Run only specific steps when reusing part of a workflow:

# Steps 1-3 only (e.g., navigate and scrape, skip save)
python3 ${CLAUDE_PLUGIN_ROOT}/scripts/play.py scenario.json --start 1 --end 3 --json

Error Handling

Result Interpretation

Success:

{ "success": true, "passed_steps": 3, "total_steps": 3 }

Failure:

{ "success": false, "failed_step": 2, "error": "Element not found" }

Recovery Strategy

1. Analyze error (MCP response + step context)
2. Determine cause:
   • Transient: Retry with --start <failed_step>
   • Structural: Page/API changed, scenario needs update
3. Fix and re-run, or report to user

Per-Step Error Modes

Mode	Behavior
"stop"	Stop execution (default)
"skip"	Continue to next step
"retry"	Retry with exponential backoff

Sandy Built-in Tools

Tools with sandy__ prefix don't require MCP servers.

Tool	Purpose
sandy__wait	Wait for duration (no MCP timeout limit)
sandy__log	Log message to output
sandy__append_file	Save data to file (jsonl/csv/json)
sandy__wait_for_element	Wait for CSS selector
sandy__wait_until	Wait for JS expression to be true

Details: See ${CLAUDE_PLUGIN_ROOT}/references/schema.md#sandy-internal-tools

Reference

• Schema: ${CLAUDE_PLUGIN_ROOT}/references/schema.md
• Examples: ${CLAUDE_PLUGIN_ROOT}/assets/examples/
• Scenario storage: .sandy/scenarios/ (project-local)