- Media store: reject malformed redirect `Location` headers as media-download failures instead of letting URL parsing escape the async response callback.

- ClickClack: skip malformed realtime websocket frames instead of stopping the channel monitor on a single bad JSON event.

- Browser tool: treat malformed node proxy `payloadJSON` responses as browser proxy failures instead of leaking raw JSON parser errors.

- Gateway HTTP: match models, session kill, and session history route paths without trusting malformed Host headers, avoiding pre-auth 500s on those endpoints.

- Models config/auth: stop inferring provider env-var markers from broad `^[A-Z_][A-Z0-9_]*$` strings, and resolve config-backed provider `apiKey` values only through structured env SecretRefs (`secrets.providers[id]` / `secrets.defaults`), so unrelated env vars cannot accidentally become provider credentials. Thanks @sallyom.

- Media fetch: skip allocating and buffering the response body for bodyless media responses (HEAD probes and 204-style empty bodies), avoiding wasted heap on streams that carry no payload. Thanks @shakkernerd.

- CLI/onboarding: forward provider-specific auth flags (e.g. `--openai-api-key`) through the onboarding wizard so they reach provider auth methods via `ctx.opts`, letting `--openai-api-key "$OPENAI_API_KEY"` skip the redundant "use existing env var?" prompt in non-interactive harnesses. (#81669) Thanks @sjf.