Replit MCP Server

run_repl

Start or run a Replit workspace to execute code and manage development environments directly from AI assistants.

Instructions

Start/run a Replit workspace

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "run_repl"
  }
}

Input Schema

Name	Required	Description	Default
`replId`	No	Optional repl ID (uses active repl if not specified)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jan 10, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden but offers minimal behavioral insight. It implies a state-changing action ('Start/run') but doesn't disclose what happens during execution, whether it's reversible, if it requires specific permissions, or what the expected outcome is. This is inadequate for a tool that likely initiates a workspace process.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise with a single, direct phrase that efficiently communicates the core action. There's no wasted language or unnecessary elaboration, making it easy to parse and understand at a glance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool that likely initiates a workspace execution (implied by 'Start/run'), the description is insufficient given no annotations or output schema. It doesn't explain what 'running' entails, success indicators, error conditions, or how this interacts with other tools like 'stop_repl'. More context is needed for safe and effective use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with the single parameter 'replId' documented as optional and defaulting to the active repl. The description adds no additional parameter context beyond what the schema provides, so it meets the baseline for high schema coverage without compensating value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Start/run') and resource ('a Replit workspace'), making the purpose immediately understandable. However, it doesn't differentiate this tool from sibling 'stop_repl' or explain what 'run' means in this context versus other execution-related tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided about when to use this tool versus alternatives like 'create_repl' or 'fork_repl'. The description doesn't mention prerequisites (e.g., needing an active or specified repl) or typical use cases, leaving the agent to infer context from sibling tool names alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.