<!-- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -->

Local override: $TIKA_SKILLS_LOCAL/metadata-schema/LOCAL.md (default ~/.tika-skills), read after this file, wins on conflict.

Metadata Key Registry & Schema Skill

Working with tika-metadata-schema, the committed, build-gated registry of Tika's metadata keys. File structure and the CLOSED/OPEN/TEMPLATE/UNKNOWN classification are in that module's README.md; this covers conventions, regeneration, and the traps.

The three registries

Under tika-metadata-schema/src/main/resources/org/apache/tika/metadata/:

• metadata-keys.json, closed set: every Property constant + the synthesized tk:digest:* cross-product.
• metadata-open-namespaces.json, KeyPrefix prefixes for runtime-minted names (html:, message:raw-header:, mdb-prop:).
• metadata-key-fields.json, TIKA-4797 {class, field, key} table for field-identity migration.

Committed on purpose: they are the reviewable audit trail of the key space (a rename or a dropped key shows up as a diff). Don't switch to build-time-only generation, that loses the review signal.

Regenerate (after adding/changing a Property or KeyPrefix)

tika-metadata-schema/regen.sh