# Expr-Lang

> Use this tool when you need to perform complex data manipulations, such as evaluating mathematical expressions, transforming arrays and objects, or applying conditional logic, directly within a conversation interface. It solves problems related to data analysis, calculations, and transformations, providing a simple and powerful expression evaluation engine. With support for various operations, from basic arithmetic to complex data sorting and filtering, Expr-Lang is ideal for users who require advanced data processing capabilities without leaving their AI assistant environment.

Canonical page: https://skillsregistry.net/skills/ivan-saorin-expr-lang  
JSON: https://api.skillsregistry.net/v1/skills/ivan-saorin-expr-lang

## Description

MCP Expr-Lang provides a powerful expression evaluation tool for Claude Desktop, integrating the expr-lang engine for complex data manipulations directly within Claude conversations. Developed by Ivan Saorin, this Go-based server enables users to evaluate mathematical expressions, transform arrays and objects, perform string operations, and apply conditional logic through a simple interface. The implementation supports a wide range of operations from basic arithmetic to complex data sorting and filtering, making it particularly useful for data analysis, calculations, and transformations without leaving the AI assistant environment.

## Trust

- **Trust score (0–1):** 0.99
- **Verification tier:** verified
- **Last scanned:** 2026-09-19

## Facts

- **Version:** 1.0.0
- **Skill type:** atomic
- **Execution layer:** mcp-remote
- **Runtime environment:** api
- **Category:** other
- **Updated:** 2026-09-19

## Source

- **Source listing:** [PulseMCP](https://www.pulsemcp.com/servers/ivan-saorin-expr-lang)
- **Repository:** <https://github.com/ivan-saorin/mcp-expr-lang>

## Use it

Resolve this record through the SkillsRegistry MCP server (no auth, read-only):

```
claude mcp add --transport http --scope user skillsregistry https://api.skillsregistry.net/mcp
```

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_skill",
    "arguments": {
      "slug": "ivan-saorin-expr-lang"
    }
  }
}
```

REST: `GET https://api.skillsregistry.net/v1/skills/ivan-saorin-expr-lang` · pull for local use: `GET https://api.skillsregistry.net/v1/skills/ivan-saorin-expr-lang/pull`

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SkillsRegistry indexes agent skills from public registries and GitHub. Skills we have analysed are scanned with Circle-IR and scored on six dimensions; each listing states its scan coverage. More: https://skillsregistry.net/llms.txt