@nice-code/devtools-core

Docs: nicecode.io — guides, integrations, and the full API surface. Working with an AI assistant? Point it at nicecode.io/llms-devtools.txt (the devtools suite) or nicecode.io/llms.txt (the whole stack) — the complete, current docs flattened into plain text.

The framework-agnostic core of the nice-* devtools — no React, no DOM-only assumptions beyond runtime-guarded globals. It is what the devtools panels (nice-devtools-shared + the per-suite browser devtools), the relay (@nice-code/devtools-relay), and producers (app clients and backends) all build on, so a backend can stream its telemetry to a devtools window without pulling in React.

Contents:

• Transport seam — IDevtoolsTransport + createBroadcastChannelTransport, createWebSocketTransport (relay), createFanoutTransport (span both).
• Bridge / client — DevtoolsBridge (host/producer side: register snapshot & sample scopes, dial a transport) and DevtoolsWindowClient (consumer side: multi-client fan-out, createRemoteTrafficCore).
• Protocol — the versioned hello/ready/snapshot/sample/command/backfill envelope and devtoolsChannelName.
• Window presence — focusExistingDevtoolsWindow / serveDevtoolsOpenerFocus / serveDevtoolsWindowPresence (dedupe/focus an already-open window).
• Traffic metrics — TrafficMetricsCore + ITrafficSample/window types + frameByteSize.
• Event log — EventLogCore (window-side synthesis of "what caused traffic").
• Dev gate — isDevtoolsEnabled.
• Remote (deployed staging) — createRemoteSessionCarrier / remoteSessionJoinUrl (the producer/window side of an authenticated relay session; a production-declared producer never dials), normalizeBackendDialUrl (backend dial hygiene: coerces to ws(s)://, refuses plain ws:// off-machine), and summarizeShape (the shared shape-not-values redaction that streamContents: false gates action, state and realm through).

The React panels live in nice-devtools-shared, which depends on and re-exports this package.