Variable	Default	Purpose
`MUSICAT_DB`	`musicat.db`	Badger directory
`MUSICAT_JETSTREAM_HOST`	`https://jetstream.us-east.bsky.network`	Jetstream v2 host
`MUSICAT_WINDOW_DAYS`	`90`	Window served and retained
`PORT`	`8000`	Listen port
`JETSTREAM_API_KEY`		Bearer key for the metered replay endpoints

API #

Route	Returns
`GET /`	Demo page (embedded)
`GET /health`	`200` while the process runs
`GET /ready`	`200` on the live tail, `503` while backfilling
`GET /<DID or HANDLE>`	What the account has been listening to

/<DID or HANDLE> answers with the account's listening (last 90 days) as JSON:

[
  {name: string, image?: string},
  ...
]

Adding ?format= renders the template instead:

$ curl "localhost:8000/did:plc:…?format=Listening%20to%20{name1}%20and%20{name2}"
Listening to Sabrina Carpenter and Elza Soares.

Adding ?days= narrows the window, from 1 to MUSICAT_WINDOW_DAYS:

$ curl "localhost:8000/did:plc:…?days=7"

Placeholders are {name1}..{name10} and {image1}..{image10}; one with no entry is a 422.
Substitution is raw, not HTML-escaped.
image is omitted when there is no cover.

Musicat #