agentkit

The agent reliability stack in one install. Five small, focused, zero-dep libraries that fix the boring problems every long-running agent eventually hits.

npm install @mukundakatta/agentkit

import { fit, firewall, expectSnapshot, vet, cast } from '@mukundakatta/agentkit';

What's in the box

| Symbol | From | What it does | |---|---|---| | fit, count, OverBudgetError | agentfit | Fit messages into a token budget | | firewall, wrapFetch, policy, check, PolicyViolation | agentguard | Network-egress firewall for tools | | record, traceTool, expectSnapshot, diff | agentsnap | Snapshot tests for tool-call traces | | vet, validate, vetAdapters, ToolArgError | agentvet | Validate tool args before execution | | cast, extractJson, castAdapters, CastError | agentcast | Structured-output enforcer |

adapters is re-exported as vetAdapters and castAdapters to avoid the name collision. For the full surface of any one library, use the subpath import:

import * as fitLib from '@mukundakatta/agentkit/fit';
import * as guardLib from '@mukundakatta/agentkit/guard';
// ...

Pipeline

The libraries compose into a natural agent reliability pipeline — fit → guard → snap → vet → cast:

fit messages       → fit a chat history into the model's budget
firewall fetches   → block tool fetches outside the allowlist
expectSnapshot     → diff this run's tool calls against a baseline
vet args           → validate args before each tool runs
cast output        → validate the model's structured response

You don't have to use all five — pick the ones you need. They share no state and are deliberately uncoupled.

Why a meta-package

Every individual library is one npm install away too. agentkit exists because the typical real-world setup uses three or more of them, and a single package makes the dependency story cleaner: one row in package.json, one import line, one version to bump.

Sibling MCP servers

Each library also ships as an MCP server so Claude Desktop, Cursor, Cline, Windsurf, and Zed can call them mid-conversation:

npx -y @mukundakatta/agentfit-mcp
npx -y @mukundakatta/agentguard-mcp
npx -y @mukundakatta/agentsnap-mcp
npx -y @mukundakatta/agentvet-mcp
npx -y @mukundakatta/agentcast-mcp

License

MIT