Composition and dependencies · cApp Developer Docs

Reviewed devnet payment

Your application — owns the order and stable operation ID
        |
        v
      Edge — coordinates the reviewed lifecycle
        +-- Circuit   — identity, reservation and retained attempts
        +-- Sentinel  — policy and exact-byte preflight
        +-- Latch     — wallet approval and signing
        +-- Dispatch  — bounded submission of the recorded attempt
        +-- Witness   — observation and receipts
        +-- Conduit   — configured RPC transport

Compass — optional intent/request shaping
Arena   — explicit simulation, never a hidden devnet fallback

Select uk.capp.sidecar.solana-edge and the six packages below in the same application's target configuration. Library selection is explicit: a dependency description does not install a peer for you. Recompile/repackage the application when changing the packaged selection or permissions, then test the package actually installed.

Package suffix after `uk.capp.sidecar.solana-`	Devnet configuration	Check before use
`edge`	`providerMode: devnet`, `compositionMode: auto`	The required graph is configured, not bundled simulation.
`conduit`	`direct-rpc` or `external-adapter`; `network: devnet`; `allowWriteMethods: true`	Verify observed genesis. Keep `verifyDevnet` enabled for the intended guarded connection.
`circuit`	`local-store` or an independently qualified external adapter	Saved state is readable and has capacity; an external field alone is not a working ledger.
`sentinel`	`conduit-peer`, `network: devnet`	Exact-transfer policy, simulation, fee/amount ceilings and allowed programs match the intended payment.
`latch`	Compatible devnet device/test-wallet or qualified external/native authority	The actual saved payer can approve; a declared `native-mwa` mode is not proof that this installation supplies its native bridge.
`dispatch`	`conduit-peer`, `network: devnet`, `allowSubmission: true`	Submission is enabled independently of Conduit's transport write gate.
`witness`	`conduit-peer`, `network: devnet`	Requested commitment and exact-transaction observations are available.

For a first local devnet integration, device-wallet retains a recoverable test wallet. devnet-test-wallet uses a temporary process-local key and is not a substitute for a saved wallet backup. See Latch before choosing an authority provider.

Inspect the graph without starting a payment

Copy the portable client module beside this example. Loading the module performs no network, wallet or ledger action. Call the inspector from a setup screen, then call the connection check deliberately. It returns a small display model instead of exporting raw provider configuration.

import {createSolanaClient} from './solana-client.mjs';
const client = createSolanaClient(() => window.capp?.solana);
const required = ['conduit', 'circuit', 'sentinel', 'latch', 'dispatch', 'witness'];

export async function inspectDevnetSetup() {
  const status = await client.call('edge', 'status');
  const nodes = status.composition?.nodes ?? {};
  const peers = required.map(name => {
    const node = nodes[name];
    return {
      name, selected: node?.selected === true, loaded: node?.loaded === true,
      ready: node?.status?.ready === true,
      mode: String(node?.status?.providerMode ?? 'unavailable')
    };
  });
  return {
    configuredForDevnet: status.mode === 'devnet' && status.ready === true &&
      peers.every(peer => peer.selected && peer.loaded && peer.ready),
    peers,
    issues: (Array.isArray(status.issues) ? status.issues : []).map(issue => ({
      component: String(issue.component ?? ''), message: String(issue.message ?? '')
    }))
  };
}

export async function verifyPaymentConnection() {
  const setup = await inspectDevnetSetup();
  if (!setup.configuredForDevnet) throw new Error('Resolve the selected devnet composition first');
  const observed = await client.call('conduit', 'verifyNetwork');
  return {network: observed.network, genesisHash: observed.genesisHash, verifiedAt: observed.verifiedAt};
}

Render messages as text. configuredForDevnet describes local configuration/availability: it is not evidence of funds, an unlocked wallet, a successful simulation or a successful send. verifyNetwork() makes a real provider read and can fail on a valid-looking endpoint. None of these calls creates or selects a wallet.

Useful smaller compositions

Need	Start with	Boundary
Balance, token-account or activity view	Conduit	Bounded RPC observations, not a complete indexer.
Portable payment request	Compass in `local-intent`, or the payment helper	Request terms, not signing or durable invoice storage.
Pending-operation ledger	Circuit in `local-store`	App/origin-scoped persistence, not a distributed lock.
Local metadata-policy rehearsal	Sentinel in `local-policy`	A metadata decision is not exact transaction approval.
Deterministic execution	Arena in `deterministic-local`	Simulation without custody or real trading settlement.
Simulated submission/receipt	Dispatch and Witness in `arena-peer`, plus Arena	Observe the same simulated attempt; keep simulation flags visible.
Collective-review rehearsal	Accord in `local-control`	Local reviewer labels are not authenticated threshold signatures.
Position allocation	Switchyard in `local-allocation`	Moving a record does not move funds.
Shared sampled charts	Market Pulse	Price quality/freshness is separate from transaction authority.

Edge demo auto uses selected compatible peers and internal simulation only where a peer is absent. A selected-but-unavailable peer fails. bundled-arena is an explicit choice to bypass peer composition for a demo. Neither establishes the live devnet path. The built-in payment flow does not automatically apply Accord or Switchyard policy simply because those packages are selected.

Selected but unavailable is an error

Missing selection, loaded-but-not-ready, wrong mode and unreachable provider are different faults. Preserve those distinctions in the UI. Never turn a disabled or failing selected provider into a new instance configured from application defaults.

External modes need their own implementation, authentication, network binding, durable state and conformance tests. The shared adapter schema does not cover every component that declares an external mode; see provider configuration before choosing it. Do not infer that an adapter URL names an existing hosted service.

Qualify the composition you will ship

Test one missing required peer, a wrong network, disabled writes, disabled Dispatch submission, declined approval and interrupted observation. Check that a selected unavailable peer is not replaced, a changed request under the same ID is rejected, and recovery does not need a newly created payer. Source/browser fixtures do not replace a rebuilt installed-device check.

Continue with the payment recipe, recovery and the individual Sidecar references.