agent-stack

Six small, single-concern reliability libraries for production LLM agents — published independently to npm, PyPI, and the Model Context Protocol registry. Each library is zero-dependency, under 500 LOC, and addresses one specific failure mode that production agent teams have to handle.

Paper

Backed by a peer-reviewable artifact paper with a DataCite DOI:

• DOI: 10.5281/zenodo.20074702
• Title: Six Reliability Primitives for LLM Agents: An Artifact Pattern for Stackable, Single-Concern Libraries
• Status: Under review at ASE 2026 Tools track.

The six primitives

Library	Concern	Failure mode it addresses
AgentFit	Context-window fitting	Token-aware truncation with multiple strategies. Pluggable tokenizers for OpenAI / Anthropic / open models.
AgentGuard	Network egress allowlisting	Blocks the "agent suddenly POSTs PHI / secrets to attacker.com" failure mode.
AgentSnap	Snapshot tests for tool-call traces	Catches silent regressions when a model's tool-call shape changes between deploys.
AgentVet	Tool-arg validation	Throws a ToolArgError carrying an LLM-friendly retry hint, so the next turn can self-correct.
AgentCast	Structured-output validate-and-retry	Bring-your-own-LLM JSON validator + retry loop.
AgentBudget	Per-run token + dollar caps	Hard cap with hook for early termination. Prevents runaway loops billing $1000 on a single query.

Each ships in three runtime forms: TypeScript on npm, Python on PyPI, and an MCP-server variant callable from Claude Desktop, Cursor, Continue, or any MCP client.

Install

TypeScript (npm)

npm i @mukundakatta/agentvet @mukundakatta/agentguard @mukundakatta/agentbudget

Python (PyPI)

pip install agentvet agentguard agentbudget

MCP server (Claude Desktop config)

{
  "mcpServers": {
    "agentvet": { "command": "npx", "args": ["-y", "@mukundakatta/agentvet-mcp"] },
    "agentguard": { "command": "npx", "args": ["-y", "@mukundakatta/agentguard-mcp"] }
  }
}

Source

Umbrella repo: github.com/MukundaKatta/agent-stack

Per-library repositories (TS + Python + MCP variants) — search GitHub topic agent-stack for the full list.

Why it exists

Reliability concerns for LLM agents are typically bundled into one heavy framework that asks you to adopt prompting, tool routing, and runtime governance as a single dependency. agent-stack inverts that: each concern is a separate library you can adopt à la carte without buying into a programming model.

The artifact paper documents the six primitives, the cross-cutting invariants the design enforces, the trade-offs of single-concern packaging, and the operational questions that emerge when reliability is split across many small dependencies.

Citation

@misc{katta2026agentstack,
  author       = {Katta, Mukunda Rao},
  title        = {Six Reliability Primitives for LLM Agents:
                  An Artifact Pattern for Stackable, Single-Concern Libraries},
  year         = {2026},
  publisher    = {Zenodo},
  doi          = {10.5281/zenodo.20074702},
  url          = {https://doi.org/10.5281/zenodo.20074702}
}

License

MIT.