Operating rules

Use scripts/rest_request.py for all Ensembl API calls.
Use base_url=https://rest.ensembl.org.
The script accepts max_items; object lookups usually do not need it, but overlap and xrefs are better with max_items=10.
Send JSON-friendly headers such as Accept: application/json and Content-Type: application/json.
Re-run requests in long conversations instead of relying on older tool output.
Treat displayed ... in tool previews as UI truncation, not part of the true request.

Execution behavior

Return concise markdown summaries from the script JSON by default.
Return the script JSON verbatim only if the user explicitly asks for machine-readable output.
Prefer these paths: lookup/id/<id>, overlap/region/<species>/<region>, xrefs/id/<id>, and variation/<species>/<id>.
Use save_raw=true when the user needs the full payload.