Configuration

spr needs no configuration to run. Everything below has a working default.

Global flags

Flag	Default	Meaning
--pace	2s	Interval between requests to one host. Never goes below 1s, whatever you pass.
--timeout	30s	Per request timeout
--retries	2	Retries on a transport error or a 5xx. Never on a challenge.
--cache	platform cache dir	Where responses are stored
--no-cache	off	Fetch fresh and store nothing
--mailto	none	Contact address for the Crossref and OpenAlex polite pools
--debug	off	One line per request on stderr
-o, --output	text	text or json
--help		Help for any command
--version		Print the version

The pace floor

--pace sets the gap between requests to a single host, and one second is a floor. Passing --pace 100ms gets you one second and a line on stderr saying so. There is no flag, environment variable or config file that lowers it, and that is deliberate: it is the one setting where the person running the tool and the site serving it want different things.

The search surface gets its own five second bucket, because it is the one that trips. Raising --pace above five seconds raises search with it.

The cache

Responses are cached for 24 hours, keyed on the url you asked for. spr cache shows the directory, how many responses are in it and how much room they take; spr cache --clear empties it. XDG_CACHE_HOME moves the default location.

A challenge and a 404 are both cached. A work that does not exist still does not exist five minutes later, and asking again for a challenge is how you get another one.

There is no user agent flag

Three user agents were measured against the search challenge, including a current Chrome string, and it treated all three exactly the same. A flag that does nothing is worse than no flag.

Environment variables

Variable	Meaning
XDG_CACHE_HOME	Moves the default cache directory