The "upstream_is_stream" JSON key flows from the AI execution report
context producer (aether-ai-serving::report_context) through several
consumers — usage runtime metadata copy/move, gateway watchdog, sync
execution decision, observability handlers, and the per-driver usage
repositories. Each site spelled the key as a bare string literal, so a
producer-side rename would silently degrade every consumer to its
fallback (typically assuming streaming) with no compile-time signal.
Introduce a single pub const UPSTREAM_IS_STREAM_KEY in
aether-ai-formats (the lowest crate every consumer already depends on),
re-export from the crate root, and route producer + all map-style
consumers through it. The change is purely a string-literal → constant
swap; behaviour is identical.
Sites left as literals (intentional):
- `json!({"upstream_is_stream": ...})` macro keys, which must be string
literals at the macro layer; these are also API-response payload
field names (an external contract that should not silently track
internal report-context renames).
- SQL column accessors (`try_get::<...>("upstream_is_stream")`), which
refer to the database schema column, not the JSON key.
- Test fixtures and assertions, which validate the on-the-wire contract
and should keep verifying the actual string.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
