MCP server

rift-mcp serves a diff to an MCP client, so the client reads a few kilobytes about two huge files instead of the files.

rift-mcp is a separate program, released next to rift. It speaks MCP over standard input and output.

Install

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/rubtsov-stan/rift/releases/latest/download/rift-mcp-installer.sh | sh

Or build it from the repository:

cargo build --release -p rift-mcp

The binary is target/release/rift-mcp.

{
  "mcpServers": {
    "rift": { "command": "/path/to/rift-mcp" }
  }
}

All three take the two paths a and b and an optional mem (64M by default, at most 256M).

Tool	What it returns
`summary`	Line and byte counts, segments by status, the first 20 differing ranges, and the memory the diff holds.
`hunks_at(line, context?, max_lines?)`	The change in or next to a line of A, as unified diff text. Defaults are 3 lines of context and 100 lines; the limits are 20 and 500. Text is also capped at 64 KiB and each line at 256 bytes.
`next_difference(after_line)`	The first differing range that starts after a line of A. Pass a returned `a.start` to step forward.

It opens regular files read-only, and refuses symbolic links, directories, devices and pipes.
It keeps the diff of each pair of files between calls, so only the first call scans them. A changed file is a new pair.
At most 4 diffs are alive, and their mem adds up to at most 512 MiB. A new pair evicts the least recently used diff that no call is using, and a diff idle for 5 minutes is dropped.