langchain-fundamentals SKILL.md skillA
langchain-fundamentals from akillness/jeo-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add akillness/jeo-skills/langchain-fundamentals@git:20260919.9f2a908Pins git:20260919.9f2a908 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- akillness/jeo-skills
- Path
.agent-skills/langchain-fundamentals/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260919.9f2a908, committed Sep 19, 2026
- Size
- 12,524 bytes
- Repository stars
- 52
- License
- none declared
Create LangChain agents with create_agent, define tools, and use middleware for human-in-the-loop and error handling.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
<oneliner>
Build production agents using `create_agent()`, middleware patterns, and the `@tool` decorator / `tool()` function. When creating LangChain agents, you MUST use create_agent(), with middleware for custom flows. All other alternatives are outdated.
</oneliner>
<create_agent>
## Creating Agents with create_agent
`create_agent()` is the recommended way to build agents. It handles the agent loop, tool execution, and state management.
### Agent Configuration Options
| Parameter | Purpose | Example |
|-----------|---------|---------|
| `model` | LLM to use | `"anthropic:claude-sonnet-4-5"` or model instance |
| `tools` | List of tools | `[search, calculator]` |
| `system_prompt` / `systemPrompt` | Agent instructions | `"You are a helpful assistant"` |
| `checkpointer` | State persistence | `MemorySaver()` |
| `middleware` | Processing hooks | `[HumanInTheLoopMiddleware]` (Python) / `[humanInTheLoopMiddleware({...})]` (TypeScript) |
</create_agent>
<ex-basic-agent>
<python>
```python
from langchain.agents import create_agent
from langchain_core.tools import tool
@tool
def get_weather(location: str) -> str:
"""Get current weather for a location.
Args:
…Read the whole file at its exact version.
How to install
mdr add akillness/jeo-skills/langchain-fundamentals@sha256:00dc50a19d6eec30The line at the top of this page pins the label git:20260919.9f2a908, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_lrjz3erhdc2w6azl)
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Versions
The registry has recorded 1 version of this file, committed on Sep 19, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12524 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
akillness/jeo-skills · 52 stars · license none declared · pushed 2026-11-05 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_lrjz3erhdc2w6azl GET https://markdownregistry.com/api/v1/resolve?ref=akillness/jeo-skills/langchain-fundamentals GET https://markdownregistry.com/api/v1/blob/00dc50a19d6eec308e3c4a5b8ca237fdddeb00195e7e29d009049f5d0566f5c2
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.