Agentmixer is a provider-neutral foundation for applications that give an agent a small, explicit tool surface. Its first consumer is Textbutler. The package's public contract and provider qualification are still being developed; see the qualification limits below before relying on any provider adapter.
Free and MIT licensed. Bun 1.3.14 or newer, or Node 22.13 or newer. First AgentMixer release in preparation.
const profile = createCapabilityProfile({
id: "notes", version: 1,
tools: [{
name: "notes.write",
description: "Replace the bound workspace's note.",
inputSchema: { /* bounded schema */ },
parseInput(input) { /* trusted parser */ },
execute(input, context) {
context.assertActive();
notes.set(context.workspaceId, input);
return { stored: true };
},
}],
});
const broker = createCapabilityBroker({
profile, workspaceId: "workspace-1", runId: "run-1",
isActive: () => hostState.active,
});
await broker.invoke("notes.write", { text: "First note." });AgentMixer supplies the execution seam: routing, custody, and a closed tool surface. Everything the agent can touch is declared by the host and bounded before the run begins.
Claude SDK, Claude API, and Codex adapters sit behind one runtime interface. An adapter stays disabled until the host proves the exact runtime, tool inventory, and confinement it claims.
Provider accounts are opaque host bindings on shared SQLite leases with generation fencing. A failed or ambiguous call retains its lease; recovery needs independent proof the old process stopped.
One workspace and one run get a closed set of file, public-web, and messaging operations. There is no shell, executable, or arbitrary RPC operation for a model to reach for.
Classifier output is strictly validated and models are selected from a fresh, host-observed catalog — never from a stale index or a model's own claims.
Applications define their own tools with createCapabilityProfile() and bind them per workspace and run. The host supplies every descriptor, parser, and handler.
createPublicWeb() admits bounded HTTPS GETs only: address pinning, per-redirect validation, no ambient credentials, a 15-second deadline, and a 256 KiB text cap.
The runtime, the broker, and the adapters share one qualification contract. There is no agent-only path behind the declared one.
Route one qualified agent run with an explicit request: route, account, profile, model, effort, and limits.
import { AgentMixer } from "@hraness/agentmixer";
const mixer = new AgentMixer({ adapters, catalog });
const result = await mixer.run(request, broker);Define application-owned tools and bind them to one workspace and run, with host-supplied parsers and handlers.
const broker = createCapabilityBroker({
profile, workspaceId, runId, isActive,
});
await broker.invoke("notes.write", input);
await broker.close();Claude SDK, Claude API, and Codex adapters behind explicit runtime qualification.
The first AgentMixer release is in preparation.
AgentMixer refuses to let model output become authority, and refuses to let a lease lapse become a takeover.
These rules are enforced by the runtime, the broker, and their tests — not by convention.
First AgentMixer release in preparation
AgentMixer is being prepared for its first release. Check published releases or read the documentation.
A provider-neutral TypeScript package for applications that run coding agents. It supplies the adapter interface, account-lease custody, model selection, and a scoped tool broker; the application supplies workspaces, credentials, and authorization.
Claude through the Agent SDK and a direct API adapter, and Codex through managed account, task, and session adapters. Every adapter must pass explicit runtime qualification before it can run — an unqualified adapter stays disabled.
Textbutler, the macOS message-butler daemon, is the first consumer. Its contact-confined workspace and brokered messaging are built on these contracts.
There is no shell, no arbitrary process execution, no plugin loading, and no RPC escape hatch. Messaging ports stage recipient-bound proposals and return an intent ID; only the application's dispatch boundary can send.
Each release is an immutable GitHub Release with a packing receipt, checksums, and signed provenance. The same archive bytes are published to npm from the tag workflow through OIDC trusted publishing.
Ben Guo, a musician and builder, formerly a founder and engineering leader at companies including Venmo and Stripe, now building from Puerto Rico. AgentMixer is published by Hraness under the MIT license.
AgentMixer is built by Ben Guo, a musician and builder, formerly a founder and engineering leader at companies including Venmo and Stripe, now building from Puerto Rico. It is published by Hraness under the MIT license.
Add the package, bind one capability profile, and qualify the exact runtime before anything runs.
Free and MIT licensed. Bun 1.3.14 or newer, or Node 22.13 or newer. First AgentMixer release in preparation.