chio-test-harness

Shared live-daemon harness consumed by the chio plugin smoke tests (ST.2.x: chio-claude-code-plugin, chio-open-code-plugin, chio-codex-plugin) and the @chio/bridge live integration test (bun run test:live).

The harness boots real chio subprocesses:

Service	Port	Command
trust plane	8940	chio trust serve --listen 127.0.0.1:8940 --service-token ...
MCP edge	8931	chio mcp serve-http ... -- node hello-mcp/server.mjs

No mocks. Every call to the harness exercises the same binaries a production chio bond deployment would hit.

Prerequisites

• chio binary on PATH, or set CHIO_BIN=/path/to/chio. The harness falls back to ../arc/target/release/chio if present.
• node >= 22.
• bun (only needed to install hello-mcp/ dependencies).
• Ports 8931 and 8940 free.

First-time install

cd chio-test-harness/hello-mcp && bun install

Smoke-test-agent usage

# 1. Bring the harness up. Prints READY when both services are healthy.
bash bin/start.sh

# 2. Source the env vars every smoke test expects.
source bin/env.sh

# 3. Drive the plugin under test. Every plugin smoke test reads:
#    - $CHIO_TRUST_URL     (http://127.0.0.1:8940)
#    - $CHIO_MCP_URL       (http://127.0.0.1:8931)
#    - $CHIO_TOKEN         (bearer for both services)
#    - $CHIO_POLICY        (path to policy/canonical.yaml)
#    - $CHIO_BIN           (absolute path to chio)
#    - $CHIO_HARNESS_DIR   (this directory)

# 4. Tear everything down.
bash bin/stop.sh

start.sh is idempotent: re-invoking it while the daemons are alive prints READY and exits 0 without restarting. To force a clean start, call stop.sh first.

Layout

bin/
  start.sh        spins trust + edge, waits for readiness
  stop.sh         kills PIDs, removes pid files, keeps logs
  wait-ready.sh   polls /health and MCP initialize until both 200
  env.sh          source-able CHIO_* env vars

policy/
  canonical.yaml     HushSpec 0.1.0 reference policy for happy-path tests
  tiny-budget.yaml   same shape with a 3-invocation velocity window
  extensions.yaml    extensions.chio.* passthrough exercises

hello-mcp/
  server.mjs         stdio MCP server with echo / delete_file / paid_action
  package.json       pinned to @modelcontextprotocol/sdk 0.6.0 (see caveat)

var/                 runtime state (pid files, logs, tokens) — gitignored

MCP SDK pin caveat

chio mcp serve-http forwards the client's capabilities.sampling.tools: true down to the wrapped MCP subprocess. @modelcontextprotocol/sdk >= 0.7 rejects that input as "unknown field" and returns JSON-RPC -32603 on initialize. We pin 0.6.0 here so the edge boots cleanly; once chio's adapter gates this behind a protocol negotiation, the pin can relax. See /Users/connor/Medica/backbay/standalone/arc/crates/chio-mcp-adapter/src/transport.rs:982 for the forwarded capabilities shape.

Canonical policy caveats

The canonical policy intentionally avoids two fields that otherwise make the happy path impossible against a bare chio check / chio mcp serve-http:

• human_in_loop.approve_above — compiles to Constraint::RequireApprovalAbove on every tool grant, which fail-closes when a governed_intent is absent. Smoke tests that need to exercise HIL threshold semantics must mint their own policy and drive chio through bridge.check({ governed_intent: ... }) (not yet surfaced on @chio/bridge@0.1.0 — see VERIFY.md).
• rules.velocity.max_spend_per_window — the velocity guard fail-closes when the matched grant lacks max_cost_per_invocation. chio check's synthetic grant does not carry that field, so the canonical policy uses max_invocations_per_window instead. The spend-window path exists in the Rust guard but requires a policy + capability combo that carries per-tool cost ceilings.

Both limits are tracked in the parent VERIFY.md so the wave-2 plugin-rewrite agents can code around them.

What to assert in downstream smoke tests

Minimum coverage every plugin smoke test (ST.2.x) must assert:

1. bond({ policyPath: "$CHIO_POLICY" }) returns a did:chio: subject and a non-empty capabilityId.
2. check({ tool: "echo", params: { msg: "hi" } }) returns decision: "allow".
3. check({ tool: "delete_file", params: { path: "/etc/hosts" } }) returns decision: "deny".
4. At least one receipt is returned from receipts({ since: T0 }) after a successful echo call, and every receipt passes verifyReceipt() (ed25519 signature valid).
5. Plugin-specific CLI surface (claude chio bond, opencode plugin chio ..., codex chio ...) is exercised end-to-end against the running harness — no stubbed ChioBridge allowed.

See /tmp/chio-debate/SMOKE_HARNESS_VERIFY.md for the reference run.

CI

Workflow: .github/workflows/ci.yml. Runs lint/typecheck (non-blocking in Wave 5.1), unit tests, and a chio-backed smoke pass. Swap owner/... once the GitHub org is live.