edgecrab-core

Why this crate? Reasoning + tools alone don't make an agent. You need a loop that knows
when to call a tool, when to stop, how to compress a 200-message history without losing
context, and which of 14 LLM providers to route to. edgecrab-core is that loop — the
orchestration brain that turns raw LLM calls and tool results into coherent, goal-directed
behaviour.

Part of EdgeCrab — the Rust SuperAgent.

What's inside

Module	Responsibility
`agent.rs`	`AgentBuilder` + `Agent` — hot-swap model, streaming, session binding
`conversation.rs`	`execute_loop()` — the ReAct tool-call loop (max 90 iterations)
`prompt_builder.rs`	System prompt assembly from ~12 sources (identity, memory, skills, AGENTS.md …)
`compression.rs`	Context compression: structural fallback + LLM-based summarisation
`model_catalog.rs`	13 providers × 200+ models — single source of truth, user-overridable YAML
`model_router.rs`	Provider factory + smart routing
`pricing.rs`	Token cost calculation per provider
`sub_agent_runner.rs`	Sub-agent delegation runner

Add to your crate

[dependencies]
edgecrab-core = { path = "../edgecrab-core" }

Simple usage

use edgecrab_core::{AgentBuilder, Agent};
use edgecrab_tools::ToolRegistry;

let registry = ToolRegistry::default();  // all built-in tools
let agent: Agent = AgentBuilder::new("anthropic/claude-opus-4.6")
    .tools(registry)
    .build()?;

// One-shot chat
let reply: String = agent.chat("Refactor this function for clarity").await?;
println!("{reply}");

Streaming usage

use edgecrab_core::StreamEvent;
use tokio::sync::mpsc;

let (tx, mut rx) = mpsc::unbounded_channel::<StreamEvent>();
agent.chat_streaming("Explain the ReAct loop", tx).await?;

while let Some(event) = rx.recv().await {
    match event {
        StreamEvent::Token(t) => print!("{t}"),
        StreamEvent::ToolCall { name, .. } => println!("\n[tool: {name}]"),
        StreamEvent::Done => break,
    }
}

ReAct loop in brief

while turns < max_iterations && budget.ok() {
    if context > threshold → compress_with_llm()
    response = provider.chat(model, messages, tools)
    if response.has_tool_calls()  → dispatch tools → push results
    else                          → return final text
}

Prompt caching note

The system prompt is assembled once per session and cached.
Do not rebuild or mutate it mid-conversation — this invalidates Anthropic's prompt cache and multiplies costs. The only sanctioned mid-session mutation is /compress.

Model catalog

# ~/.edgecrab/models.yaml  (user overrides — merged on top of defaults)
providers:
  - name: anthropic
    models:
      - id: claude-opus-4.6
        context_window: 200000
        cost_per_1m_input: 15.00
        cost_per_1m_output: 75.00

Full docs, guides, and release notes → edgecrab.com

edgecrab-core 0.3.4