| name | lean-ctx |
| description | Context Engineering for AI Agents — 81 MCP tools, 10 read modes, 95+ shell patterns, tree-sitter AST for 27 languages. Compresses LLM context by up to 99%. Use when reading files, running shell commands, searching code, or exploring directories. Auto-installs if not present. |
lean-ctx — Context Engineering for AI Agents
Setup
which lean-ctx || curl -fsSL https://raw.githubusercontent.com/yvgude/lean-ctx/main/skills/lean-ctx/scripts/install.sh | bash
lean-ctx setup
Core Tools (10 always visible)
| Tool | Purpose |
|---|
ctx_read(path, mode) | Read file with compression and caching |
ctx_search(pattern, path) | Search code with compressed results |
ctx_shell(command) | Run shell with compressed output |
ctx_tree(path, depth) | Directory listing |
ctx_patch(path, ops) | Anchored editing (line+hash, no old-text echo) |
ctx_session(action) | Session state and persistence |
ctx_knowledge(action) | Project knowledge across sessions |
ctx_overview(task) | Task-relevant project map |
ctx_graph(action) | Code relationships and impact |
ctx_call(name, args) | Invoke any tool by name |
Shell Hook (use instead of raw exec)
lean-ctx -c "git status"
lean-ctx -c "cargo test"
lean-ctx -c "npm install"
lean-ctx ls src/
ctx_read Modes
| Mode | When |
|---|
anchored | Files you will edit (full text + N:hh| anchors for ctx_patch) |
full | Verbatim cached read |
map | Context-only (deps + exports) |
signatures | API surface only |
diff | After edits (changed lines) |
aggressive | Large files, syntax-stripped; JSON arrays row-deduped (lossless) |
entropy | Shannon filtering |
task | Task-relevant lines |
lines:N-M | Specific range |
auto | System selects optimal |
Re-reads cost ~13 tokens. fresh=true bypasses cache.
Redundant JSON (arrays of like objects) is crushed losslessly into a compact
_defaults + per-row form; if a slice was dropped, recover it with
ctx_expand(id, json_path=… | search=…).
File Editing
Anchored editing saves output tokens: ctx_read(mode="anchored") → ctx_patch(path, op, line, hash, new_text).
Never reproduce old text byte-for-byte; batch via ops:[…]; op=create writes new files.
Stale anchor → CONFLICT with fresh anchors (retry once). Native Edit/StrReplace stay fine;
ctx_edit (str_replace) is the legacy fallback via ctx_call/power profile.
More Tools (via ctx_call or ctx_load_tools)
Architecture: ctx_symbol, ctx_callgraph, ctx_impact, ctx_architecture, ctx_routes, ctx_smells, ctx_quality
↳ "What breaks if I change this file/class/type?" → ctx_impact (file-level blast radius; resolves same-package/namespace type usage with no import for C#, Java, Go and Kotlin). "Who calls this function?" → ctx_callgraph (symbol-level). "How navigable / how much is complexity costing me?" → ctx_quality (navigability score + token quality tax).
Multi-agent: ctx_agent, ctx_share, ctx_task, ctx_handoff, ctx_workflow
Verify: ctx_benchmark, ctx_verify, ctx_proof, ctx_review
Batch: ctx_fill, ctx_execute, ctx_expand, ctx_pack
Full docs: https://leanctx.com/docs
