---
title: "Runtime conformance"
description: "The executable vectors a runtime must pass, the checklist behind them, what the suite does not cover yet, and how to run it against your driver."
canonical: https://harnesscontextprotocol.io/docs/runtimes/conformance
---

# Runtime conformance

> The executable vectors a runtime must pass, the checklist behind them, what the suite does not cover yet, and how to run it against your driver.

A runtime conforms when it passes the vectors and meets the checklist, and both
are executable. Point the vectors at your own driver, work through the checklist
for what they do not test yet, then report the result.

## Vectors

The protocol's vectors ship in the SDK and use `transit` and `ledger` as
fixtures:

```bash
cd hcp/packages/sdk && bun test src/conformance.test.ts
```

| Vector | Passes when |
|--------|-------------|
| Lint | `transit`, `ledger`, and the composite `echo` lint clean |
| Read | `transit find` runs through the sandboxed runtime and returns the stop it resolved |
| Confirm | `transfer` without `confirm` → `{ ok: false, error: "confirm required" }`; with `confirm: true` → `ok: true` |
| Grant deny | With no grants, a read → `ok: false`, error contains `denied` |

The suite does not yet compare the twin faces, run a bin that is not
allow-listed, or lint a `wrap` with neither named commands nor `pass_through`.
The checklist still requires all three; the
[twin-face check](/docs/packs/check#the-twin-face-check) and the
[sandbox deny](/docs/packs/check#sandbox-deny) show how to test them.

## Running them against your driver

Pointing `Hcp` at your driver runs the same tests:

```ts
import { Hcp, loadPackFromDir } from '@harnesscontextprotocol/sdk'

const packs = await Promise.all([loadPackFromDir(transitDir), loadPackFromDir(ledgerDir)])
const hcp = await Hcp.create({ runtime: createAcmeRuntime({ packs, … }), grants })
await hcp.activate(['transit', 'ledger'])

expect((await hcp.exec('ledger', 'transfer', { amount: '2.80', payee: 'demo-transit' })).error).toBe('confirm required')
```

## Runtime checklist

### Loading

- [ ] Loads `surface.json`, `policy.json`, `HARNESS.md` from a directory
- [ ] Rejects a pack with any lint issue at install
- [ ] Checks `id` = `surface_id` = `pack_id`
- [ ] Rejects an unsupported `hcp` protocol affinity and reports it

### Authorisation

- [ ] Exactly one Principal per exec, from the session
- [ ] Five capability axes; none collapsed in multi-tenant deployments
- [ ] `brain` land requires project scope
- [ ] Tenant never taken from envelope args
- [ ] Denials carry a reason string
- [ ] No default-allow path

### Gates and Binding

- [ ] `confirm: true` enforced before any adapter; `confirm` / `apply` in args satisfies it
- [ ] `confirm: "always"` gated at least like `confirm: true` (draft RFC 0006)
- [ ] Mint fail-closed; no env-token fallback
- [ ] `mock` only when explicit in the envelope
- [ ] `mothership` Binding unreachable from a non-operator Principal without an elevation grant
- [ ] `connect` requires `pack.connect`, not `verb.exec.write`

### Execution

- [ ] Wrap argv rendered from `cli[]` / `argv_template`; no shell interpolation
- [ ] The JSON flag appended (`--json` unless `json_flag` says otherwise); result parsed when possible
- [ ] Non-zero exit → `ok: false` with stderr or `exit N`
- [ ] Sandbox default; unknown bin denied; cwd fixed
- [ ] `native-local` requires explicit opt-in

### Reporting

- [ ] Availability per pack: `installed`, `activated`, `connected`
- [ ] Availability per command: `executable` with `reason` when false
- [ ] Skill exposed on activate (copied to `skills/<id>/SKILL.md` or equivalent)

### Sense (if implemented)

- [ ] Activation independent of Execute
- [ ] `sense.enable` checked before any sink write; off → drop
- [ ] Undeclared refs dropped and reported
- [ ] Sink records inert and attributable
- [ ] Wake path goes through Execute grants
- [ ] `binding.degraded` produced by the hub

### Audit

- [ ] Writes attributed with `Principal + tenant (+ project) + Binding + pack_id + verb_key + operation`

## Reporting conformance

State the protocol version (`HCP/1.1`), the vector suite commit, and which
optional parts you implement (Sense, MCP export, the `openapi` adapter), then
follow [Implementations](/docs/community/implementations) to be listed.

## Related

- [Specification: Conformance](/docs/specification/conformance): the normative checklist for packs, runtimes, and hosts

## Sitemap

- [Documentation](https://harnesscontextprotocol.io/docs)
- [Packs](https://harnesscontextprotocol.io/packs)
- [Glossary](https://harnesscontextprotocol.io/docs/reference/glossary)
- [llms.txt](https://harnesscontextprotocol.io/llms.txt)
- [llms-full.txt](https://harnesscontextprotocol.io/llms-full.txt)
- [OpenAPI](https://harnesscontextprotocol.io/openapi.json)
- [MCP](https://harnesscontextprotocol.io/mcp)