Is this URL in the index?

get /why_not

Request

curl \
  -H "x-api-key: $UNLOB_API_KEY" \
  "https://api.unlob.com/why_not?url=<url>"

Behaviour

Answers one of three things. `present` returns the hit. `removed` names the reason — redundant, superseded, stale, access-starved, lost-replacement, or tombstoned-source — and, where one exists, the passage that superseded it. `unknown` means it was never admitted, or was never seen.

Use it before concluding the web is silent on something: an absent URL and an absent topic are different findings.

Parameters

Name	Type	Description
`url`required	string	The URL to ask about.

Responses

Status	Meaning
`200`	present, removed (with a reason), or unknown.
`401`	Missing, unknown or revoked key. A key minted moments ago can answer 401 until it propagates to the serving fleet.
`429`	Over the per-minute rate, or past a hard-capped monthly quota. `retry-after` is present on the rate-limit case only.

The same call over MCP is a tool with these parameter names unchanged. See Errors for what to do with each status.