engram

engram-ccode

A Claude Code plugin that adapts Engram's identity-aware compression to reduce context window token usage in coding sessions.

What It Does

Every Claude Code session re-reads the same CLAUDE.md files describing your project's conventions. engram-ccode compresses that project identity into a compact key=value format at session start — typically reducing 150–200 tokens of prose to 30–40 tokens — and monitors for redundant identity reinforcement throughout the session.

Example compression:

# CLAUDE.md prose (~187 tokens):
"This is a Go server using structured logging with slog.
Error handling returns errors wrapped with fmt.Errorf.
Every public function takes context.Context as first param.
Tests are table-driven using testify..."

# Compressed (~34 tokens):
[identity]
arch=modular_monolith concurrency=errgroup_ctx_cancel err_style=wrap_errorf
lang=go logging=slog pkg_style=no_circular testing=table_driven_testify
[/identity]

Architecture

Three components work together:

Component	What It Does
MCP Server (server/index.mjs)	stdio-based server exposing 5 compression tools
Hooks (hooks/)	SessionStart compresses identity; PostToolUse detects redundancy
Skills (skills/)	/report, /codebook, /config slash commands

MCP Tools

Tool	Purpose
derive_codebook	Extract structured dimensions from CLAUDE.md via pattern matching
compress_identity	Serialize dimensions to deterministic key=value format
check_redundancy	Compare tool output against active codebook
get_stats	Return session token accounting
generate_report	Produce markdown savings report

Detected Dimensions

Auto-derived from CLAUDE.md without LLM calls:

lang · framework · build · testing · err_style · logging · arch · concurrency · transport · pkg_style

Override any dimension via .engram-codebook.yaml in your project root.

Skills

Skill	Description
/engram-ccode:report	Generate a token savings report for the session
/engram-ccode:codebook	Show, diff, init, or validate the active codebook
/engram-ccode:config	Manage redundancy threshold, pricing, and notification settings

Per-Project Files

<project-root>/
├── .engram-codebook.yaml     # optional dimension overrides
└── .engram/
    ├── codebook-cache.json   # SHA-256-invalidated codebook cache
    ├── config.yaml           # plugin settings
    └── savings-log.csv       # cross-session savings history

Design Constraints

• No LLM calls during compression — pure pattern matching
• Never modifies tool output — PostToolUse hook is passive/observational only
• Local only — no network calls, no telemetry
• Deterministic — same CLAUDE.md always produces same codebook

Requirements

• Node.js 20+
• Claude Code with plugin support

Installation

See INSTRUCTIONS.md.

License

MIT © 2026 Erik Meyer