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Sem MCP

Semantic version control on top of Git — see which functions, classes and methods changed, what depends on them, and what breaks.

by Ataraxy-Labs ↗Code Intelligence & Repository IndexingCommunity

LABSCO SUMMARY

One name collision to check before you install.

GNU Parallel ships its own sem binary at /usr/bin/sem; if you have both, run sem --version to see which one wins and fix your PATH or alias. Past that, the argument for wiring it into an agent is token cost — asking what breaks if submitOrder changes gets a precise answer from the dependency graph instead of reading files until the agent is confident.

What it is

A Rust CLI that parses your code with tree-sitter, extracts every function, class and method as an entity, and diffs at that level rather than by lines. sem mcp starts an MCP server over stdin/stdout so a coding agent can ask those questions while it works.

What you get

  • Six entity-level tools for agents — sem_impact, sem_context, sem_diff, sem_entities, sem_blame, sem_log
  • What breaks if an entity changes, from a cross-file dependency graph, narrowable to direct dependencies, direct dependents or affected tests — sem_impact
  • Just the context needed to refactor one function, instead of reading whole files — sem_context
  • Entity-level diffs with rename detection, structural hashing and word-level inline highlights, over working changes, staged changes, a commit or a range — sem_diff
  • Entity-level blame showing who last touched each function, class or method — sem_blame
  • One entity's history through git, so you can see how a single function evolved — sem_log
  • The same operations from the CLI with plain, JSON and Markdown output, plus comparison of two files with no git repo at all

Requirements

The binary — install script, brew install sem-cli, winget, Scoop, npm install --save-dev @ataraxy-labs/sem, cargo install, a GitHub release, or Docker. sem mcp ships in the same binary, so there is nothing extra to install; register it with claude mcp add sem -- sem mcp or point any mcpServers config at the sem command. The SQLite entity cache lives outside the repository under the OS cache directory, overridable with SEM_CACHE_DIR. Cloud-backed queries are opt-in per repo — logging in does not upload a repo or send a query. Version 0.16.2, MIT licensed.

Setup effort

One command — curl -fsSL https://raw.githubusercontent.com/Ataraxy-Labs/sem/main/install.sh | sh

See installation options