tai42-skeleton

The open-source implementation of tai42-contract — the extended MCP server that hosts tools, agents, extensions, connectors, hooks, and storage for the TAI ecosystem. It provides the concrete TaiMCP server and the runtime engines (tool registry and adapters, the agent registry, the OAuth connector engine, the access-control middleware, the hooks router, the template/storage manager, the manifest loader, and the transport layer) that implement the protocols declared in tai42-contract.

Providers — OAuth connectors, storage backends, config providers, worker backends, monitoring — ship as separate plugins that register through the tai42_app contract handle when the manifest loads them; no plugin imports the skeleton.

Position in the ecosystem

TAI is an open-source runtime for MCP tools, agents, and workflows — the server that hosts a capability and supplies the operational layer around it (manifest loading, access control, OAuth connectors, background execution, monitoring, storage, and human-in-the-loop steps).

Three packages; each depends only on the ones to its left:

tai42-contract  <--  tai42-kit  <--  tai42-skeleton
(interfaces)      (helpers)     (the server)

tai42-skeleton is the server at the end of the chain: it depends on only tai42-contract (the pure interface package) and tai42-kit (generic leaf helpers). It is the runnable body every plugin plugs into.

Install

Requires Python 3.13+. Install from PyPI into the environment that runs the server:

uv add tai42-skeleton

Or from source:

git clone https://github.com/tai42ai/tai42
cd core/skeleton
uv venv --python 3.13
uv pip install --no-sources --editable .

Add the toolbox extra for batteries — it pulls in the tai42-toolbox contrib package, whose composition tool extensions (chain, batch) and generic tool collection load from the manifest (see examples/toolbox):

uv add "tai42-skeleton[toolbox]"                      # from PyPI
uv pip install --no-sources --editable ".[toolbox]"   # from a source checkout

Run it

The hello-world app in examples/hello registers one local greet tool and needs no services to stand up. From the repo root:

ACCESS_CONTROL_ENABLE=false \
PYTHONPATH=examples/hello \
uv run --no-sync tai serve --manifest-path examples/hello/manifest.yml --port 8765

The MCP endpoint is then http://127.0.0.1:8765/mcp, and it lists 94 tools, not one: alongside greet the server projects 93 operation tools from its own management operations, because the manifest's api_tools block is on by default. Set api_tools: {enabled: false} to switch that projection off and leave greet on its own. The server also polls the marketplace for security advisories on a timer — that is its one outbound call, and MARKETPLACE_ADVISORIES_POLL=false turns it off.

tai backend runs the agent/worker backend process and tai metrics serves the Prometheus endpoint; the full command surface is in the CLI reference below.

tai serve, tai backend, and tai metrics form one run family over a single shared Prometheus multiprocess directory (PROMETHEUS_MULTIPROC_DIR, default a fixed absolute path under the host temp dir; any override must be absolute). Point all three at the same directory and restart them together: tai serve clears the directory once at boot, so restarting it mid-run while a backend worker is still writing orphans that worker's counters until the whole family restarts. examples/README.md walks through the examples, and examples/manifest.yml is the commented manifest reference.

The worker bus

When a deployment runs more than one process — several tai serve workers, a tai backend runtime alongside the server, or multiple pods sharing one config — a manifest edit on one process must reach the others, or siblings serve stale state. The worker bus is how every process converges: each subscribes to one Redis channel at startup, a mutation applies locally and is then broadcast, and the response carries a per-origin report of how every worker fared.

The bus is internal app infrastructure, like the reload gate — it is NOT a plugin. Nothing about it is registrable, swappable, or user-selectable; there is exactly one bus and no manifest field chooses an implementation. It is configured only by environment: set TAI_BUS_REDIS_URL (plus the optional TAI_BUS_* knobs) to turn it on. A single-worker, file-mode, no-backend deployment needs no bus and runs on a no-op local variant; a multi-worker, backend-bearing, or k8s-mode boot refuses to start without one, naming TAI_BUS_REDIS_URL. On a shared Redis, TAI_BUS_NAMESPACE must diverge per stack — Redis pub/sub is server-global, so co-tenant deployments would otherwise cross-talk.

Development

Set up the dev venv and run the gates. --no-sources ignores the workspace-source overrides in [tool.uv.sources], so the dev deps come from PyPI and the clone stands alone; --no-sync runs each gate against that environment instead of re-resolving:

uv venv --python 3.13
uv pip install --no-sources --editable ".[dev]"
uv run --no-sync ruff check .
uv run --no-sync ruff format --check .
uv run --no-sync pyright
uv run --no-sync pytest --cov --cov-report=term-missing

See CONTRIBUTING.md for the rules.

Documentation

The whole platform — the quickstart, concepts, guides, and the generated reference — lives in the unified documentation site:

• Getting started & install: https://tai42.ai/getting-started/installation
• Quickstart: https://tai42.ai/getting-started/quickstart
• Concepts: https://tai42.ai/concepts
• Guides: https://tai42.ai/guides
• Built-in tools & extensions: https://tai42.ai/concepts/tools-and-extensions
• Reference (HTTP API, CLI, Python SDK): https://tai42.ai/reference/cli

License

Apache-2.0. See LICENSE and NOTICE.