Framework-free AI agents built with bash, curl, and jq

llayer is an experiment in applying the Unix philosophy to large language model orchestration. Everything is handled through a suite of small, single-purpose commands interfacing over standard text pipes to produce a REPL-style agent loop.

Why?

Agent frameworks can be state-heavy and hard to reason about. llayer deconstructs the agent lifecycle into fundamentals:

• State & Memory: An append-only .jsonl history file (like .bash_history).
• Context Window: A functional jq stream reducer.
• Agent Loop: A standard bash while loop.

Because the entire architecture is a stateless text pipeline, it unlocks neat capabilities, such as:

• ⏱️ Time-Travel Debugging: instantly rewind the agent's memory by slicing the history file (e.g., head -n 20 .llayer_history).
• 🛠️ Zero Abstraction Tooling: add tools using pure Bash functions where stdout directly becomes the agent's input.
• 🚀 Native Pipelining: intercept the agent's stream with standard POSIX tools - e.g. filter PII data with grep before it hits the model, or natively benchmark token streaming speeds using pv.

Quick Start

To get started: clone this repo, start a local model server (Ollama) with docker compose, then call agent:

% docker compose up --detach
...
 ✔ Container llayer-ollama-1 Started
% ./agent 
> Hello there, good morning 
Good morning to you as well! How's your day starting out so far?

Alternatively, try out the individual commands. For example, a stateless, context-free call is simply a chain of commands:

% echo "Hello, world" | ./ll-read | ./ll-context | ./ll-eval | ./ll-print
Hello! It's nice to meet you. Is there something I can help you with or would you like to chat?

The Stateful Agent: a REPL

graph LR
    User

    subgraph READ
        ll-read
        History
        ll-context
    end

    subgraph EVAL
        ll-eval
        ll-dispatch
        Model
        Tools
    end

    subgraph PRINT
        ll-print
    end

    User -->|read| ll-read
    ll-read -->|append| History
    History -->|pipe| ll-context
    ll-context -->|pipe| ll-eval
    ll-eval -->|append| History
    ll-eval -->|pipe| ll-dispatch
    ll-dispatch <-->|call|Tools
    ll-dispatch -->|append| History
    ll-eval -->|pipe| ll-print
    ll-eval <-->|http| Model
    ll-print -->|print| User

    style ll-read fill:#4A90E2
    style ll-context fill:#4A90E2
    style ll-eval fill:#4A90E2
    style ll-dispatch fill:#4A90E2
    style ll-print fill:#4A90E2

The agent script combines the standalone components to form a read-eval-print loop (REPL) that largely resembles an AI agent:

1. ll-read user input and append a corresponding event to the history file.
2. Build ll-context from history to produce the model context and ll-eval the model.
3. If necessary, ll-dispatch to supported tools and append the result to the history; repeat step 2.
4. Append model output as events to history then ll-print to display messages to the user.

Power of Pipes

Caling specific components of the agent is straightforward. Examples include inspecting and adding to the context passed into the model:

(cat .llayer_history && echo "Print some digits of PI" | ./ll-read) | ./ll-context | jq -c '.[]'

Or replaying agent messages from history:

cat .llayer_history | ./ll-print --debug

Or directly inspect streamed model outputs:

echo "ping! just reply pong" | ./ll-read | ./ll-context | ./ll-eval            

Or pipe to a downstream tool to measure how quickly the model is streaming responses back, and buffer all of the output before printing the responses:

echo "How much wood could a woodchuck chuck?" | ./ll-read | ./ll-context | ./ll-eval | pv --line-mode | sponge | ./ll-print

Implementation

Append-Only State

An append-only history file stores all of the state. Each line is an event JSON object describing either a user input, a token emitted by the model, a completed message, or a tool call/result. Motivations and goals of this design:

• Immutability: all events, down to individual tokens, are preserved for auditing, debugging, and replayability.
• Simplicity: using append-only text to store state is robust and aligns with the minimalist philosophy.
• Composability: downstream tools can consume, filter, and transform the event stream without modifying state.

Context Building

ll-context compacts the canonical event history to build the context for each model call. Its main purposes are:

• Scoping: the command filters history down to relevant events, groups tokens into higher-level messages, and applies configurable heuristics (e.g. keep last N turns, strip tool-call payloads, collapse tokens into a single assistant message) so the model receives concise context.
• Reduction: the original history is never rewritten or deleted; the command reduces the history down to a filtered, model-friendly sequence derived from events that fall within a user-defined window.

Schema

The individual components utilize a DSL that follows minimal, explicit JSONL shapes where each line contains a type, source, and payload. The basic event schema is as follows:

{"type": "error",            "source":"system",     "payload": {"test": "..."}}
{"type": "message",          "source": "user",      "payload": {"text": "..."}}
{"type": "message_complete", "source": "system",    "payload": {}}
{"type": "token",            "source": "assistant", "payload": {"text": "..."}}
{"type": "tool_call",        "source": "assistant", "payload": {}}
{"type": "tool_result",      "source": "tool",      "payload": {}}