LangBot/docs/architecture/certified-plugins.md

Certified Plugins

Admission boundary

Core verifies a plugin archive before artifact storage, PluginSetting persistence, or a Plugin Runtime apply request. It calls the SDK public langbot_plugin.certification.verify_archive() API, which reads the strict certificate envelope from the ZIP comment and verifies the signed normalized ZIP digest without extracting the payload.

Core retains the artifact SHA-256, normalized digest (normalized_zip_digest()), verification state, declared shared-runtime profile, stateless-v1 component model, key ID, selected admission profile, and stable admission code in the durable plugin install_info._certification record. The record belongs to the installation row; no schema migration is needed for this additive JSON metadata.

Trusted issuer configuration

Configure the non-secret Ed25519 public-key ring in data/config.yaml:

plugin:
  certification:
    trusted_public_keys:
      issuer-2026-q3: "<base64 encoded 32-byte Ed25519 public key>"

Key IDs must match the SDK envelope. Values are standard base64 raw public keys, not private/signing keys. An invalid key-ring configuration is rejected rather than weakening verification. Keep active issuer keys during a rotation until archives signed by retired IDs are no longer installed.

The ring may also be supplied out-of-band, which is how hosted deployments provision it:

PLUGIN__CERTIFICATION__TRUSTED_PUBLIC_KEYS_JSON='{"ed25519:issuer":"<base64>"}'

An empty ring is a supported state, not a misconfiguration. OSS defaults to it, so a self-hosted instance that has not provisioned any issuer key still installs packages (see the admission matrix below). Configure the ring to grant the shared-runtime profile; leave it empty to keep every package on the dedicated profile.

Admission matrix

Deployment	SDK verification	Explicit administrator_force	Result
Cloud	valid envelope declaring shared-runtime-v1 + stateless-v1	any	admitted to the shared singleton profile
Cloud	no signature	any	install on dedicated worker, without shared eligibility
Cloud	malformed, untrusted, invalid, or non-shared declaration	any	reject before storage with CERTIFIED_PLUGIN_CLOUD_CERTIFICATE_INVALID; do not treat a broken signature as unsigned
OSS	absent legacy envelope	any	admitted to the dedicated profile
OSS	valid envelope declaring shared-runtime-v1 + stateless-v1	any	selected shared singleton profile
OSS	declaration signed by a key this instance resolves	false	reject with CERTIFIED_PLUGIN_OSS_FORCE_REQUIRED
OSS	declaration signed by a key this instance resolves	true	admitted to the dedicated profile
OSS	declaration this instance cannot resolve (empty ring)	any	admitted to the dedicated profile

The OSS row that matters for availability is the last one. Marketplace packages are signed by the marketplace issuer and declare shared-runtime-v1, while OSS ships an empty key ring by default. Treating that as a rejection made every certified marketplace package uninstallable with CERTIFIED_PLUGIN_OSS_FORCE_REQUIRED before artifact storage. Because the certificate is signed by an issuer the instance does not declare trusted, no shared-runtime privilege may be granted, so admission degrades the install to the existing oss_dev dedicated profile and records CERTIFIED_PLUGIN_OSS_UNTRUSTED_DEDICATED. This is not an escalation: it withholds the shared profile rather than granting it.

A declaration is "resolvable" only when its key_id is present in the configured ring. A parseable declaration from a resolved key that fails signature, digest, identity, profile, or component-model validation requires administrator_force in OSS. Malformed or unsupported envelopes without a resolved certificate identity are treated as untrusted and stay dedicated.

administrator_force is deliberately strict: it is recognized only when the install request carries boolean true. The local upload endpoint accepts the multipart field administrator_force=true; GitHub and marketplace install payloads carry the same field. The existing resource-manage authorization fence protects those endpoints. A force never creates a Cloud dedicated fallback.

Runtime and logs

The first stateless-compatible SDK release will carry the v2 certificate and singleton component contract; its final version is assigned only at release. Core must pin that release before sending or selecting the new contract. Core selects shared-runtime-v1 only when the persisted certification record says verification was valid, both the certificate and admission profiles are shared-runtime-v1, the admission code is shared-eligible, and the record's artifact SHA-256 exactly matches the installation row. Missing, malformed, stale, invalid, or dedicated admission facts select dedicated. Install, upgrade, configuration revision, restart, and reconnect all use this same persisted-fact derivation.

The certificate must also bind component_model=stateless-v1. This profile creates one BasePlugin and one instance of each component per digest Worker. Installation slots contain immutable config snapshots and authority only; task-local invocation context selects the active slot. Older certificates that do not bind the component model are not eligible for shared placement. Their source packages remain compatible on dedicated Workers under OSS policy.

The existing public plugin-log boundary already applies the immutable installation binding (including workspace UUID) through RuntimeConnectionHandler.installation_scope() before requesting logs. This is the actual tenant exposure boundary, so valid shared certificates use that binding-scoped transport; Core does not invent a second log stream or expose process-wide log output. Dedicated and invalid/legacy installations use the same existing installation scope.

SDK versioning

Ship in dependency order: SDK v2 certificate support, then Core exact pin and lockfile, then Space signing, then Runtime/Core rollout. Legacy v1 envelopes remain verifiable but do not carry stateless-v1, so they never select shared singleton placement without re-review and v2 re-signing.