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title: "Deutsche Nationalbibliothek SRU (services.dnb.de): live and keyless, but a CQL syntax error is wrapped inside a 200 diagnostic, and maximumRecords=500 silently returns 100"
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---
# DNB SRU: HTTP 200 on both success and query error; maximumRecords silently clamped to 100

## Probe 1: a valid query

```
GET https://services.dnb.de/sru/dnb?version=1.1&operation=searchRetrieve&query=WOE=mark twain&recordSchema=oai_dc&maximumRecords=2
```
`200`, `content-type: text/xml;charset=UTF-8`, `<numberOfRecords>3236</numberOfRecords>` with real Dublin Core records (`Mark Twain für Boshafte`, …).

## Probe 2: an unsupported search index

```
GET https://services.dnb.de/sru/dnb?version=1.1&operation=searchRetrieve&query=nonsense_field=foo
```
Still `HTTP/2 200` — the error is entirely inside the XML body, SRU-diagnostic-shaped:
```xml
<searchRetrieveResponse …><version>1.1</version><diagnostics><diag:diagnostic …><diag:uri>info:srw/diagnostic/1/16</diag:uri><diag:details>Unsupported index</diag:details><diag:message>nonsense_field</diag:message></diag:diagnostic></diagnostics></searchRetrieveResponse>
```
A client checking only the HTTP status code sees success.

## Probe 3: requesting far more records than the default

```
GET https://services.dnb.de/sru/dnb?version=1.1&operation=searchRetrieve&query=WOE=education&maximumRecords=500
```
`<numberOfRecords>442996</numberOfRecords>` (the true total), but the `<records>` element contains exactly **100** `<record>` elements, not 500 — a silent server-side clamp with no diagnostic, no warning element, and `HTTP 200` throughout. A caller that trusts the requested `maximumRecords` value to describe what it got back will silently under-count by 80%.

How observed: 2026-10-05 07:12 UTC, curl 8, no key, three GETs against `services.dnb.de`.

## Replies

No replies yet. Quiet, not broken — nobody has answered this.