How do I install the Lean Ctx skill?

Run npx skillmds@latest add spike-faye-lei/lean-ctx in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Lean Ctx safe to use?

SkillMD's automated safety review verdict for this skill is WARNING. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Lean Ctx?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Lean Ctx free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Lean Ctx?

spike-faye-lei (@spike-faye-lei) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Lean Ctx by spike-faye-lei — Agent Skill

Name: Lean Ctx
Author: spike-faye-lei

Lean Ctx

Context Runtime for AI Agents — 72 MCP tools, 10 read modes, 95+ shell patterns, tree-sitter AST for 18 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.

File contents

lean-ctx — Context Runtime 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_edit(path, old, new)`	Search-and-replace editing
`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
`full`	Files you will edit
`map`	Context-only (deps + exports)
`signatures`	API surface only
`diff`	After edits (changed lines)
`aggressive`	Large files, syntax-stripped
`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.

File Editing

Use native Edit/StrReplace. If unavailable, use ctx_edit immediately.

More Tools (via ctx_call or ctx_load_tools)

Architecture: ctx_symbol, ctx_callgraph, ctx_impact, ctx_architecture, ctx_routes, ctx_smells 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

---name: lean-ctxdescription: Context Runtime for AI Agents — 72 MCP tools, 10 read modes, 95+ shell patterns, tree-sitter AST for 18 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 Runtime for AI Agents## Setup```bashwhich lean-ctx || curl -fsSL https://raw.githubusercontent.com/yvgude/lean-ctx/main/skills/lean-ctx/scripts/install.sh | bashlean-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_edit(path, old, new)` | Search-and-replace editing || `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)```bashlean-ctx -c "git status"lean-ctx -c "cargo test"lean-ctx -c "npm install"lean-ctx ls src/```## ctx_read Modes| Mode | When ||------|------|| `full` | Files you will edit || `map` | Context-only (deps + exports) || `signatures` | API surface only || `diff` | After edits (changed lines) || `aggressive` | Large files, syntax-stripped || `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.## File EditingUse native Edit/StrReplace. If unavailable, use `ctx_edit` immediately.## More Tools (via ctx_call or ctx_load_tools)Architecture: ctx_symbol, ctx_callgraph, ctx_impact, ctx_architecture, ctx_routes, ctx_smellsMulti-agent: ctx_agent, ctx_share, ctx_task, ctx_handoff, ctx_workflowVerify: ctx_benchmark, ctx_verify, ctx_proof, ctx_reviewBatch: ctx_fill, ctx_execute, ctx_expand, ctx_packFull docs: https://leanctx.com/docs

Frequently asked questions