Inspect VRs and transfer syntaxes

Prefer structured encoding tools over broad prose search when the question matches a Value Representation or Transfer Syntax.

Look up a Value Representation

EDITION=2025e  # Replace with your concrete edition.
uv run dicom-kb lookup vr PN \
  --edition "$EDITION"

The result can include:

• the two-letter VR;
• its name;
• a parsed value-representation class;
• length notes;
• padding behavior;
• character-repertoire notes;
• a binary-or-text classification;
• a PS3.5 source reference.

Malformed VR input returns validation_error; an unknown valid two-letter code returns not_found.

Look up a Transfer Syntax

Use a UID, name, or keyword:

EDITION=2025e  # Replace with your concrete edition.
uv run dicom-kb lookup transfer-syntax ExplicitVRLittleEndian \
  --edition "$EDITION"

The result combines PS3.6 UID metadata with parsed PS3.5 encoding facts:

• UID value, name, and keyword;
• explicit or implicit VR behavior when resolved;
• endian behavior;
• encapsulation;
• compression family;
• retired status;
• bounded encoding notes.

Inspect null fields and warnings rather than inferring missing properties.

Request a cited explanation

EDITION=2025e  # Replace with your concrete edition.
uv run dicom-kb explain encoding 'Explicit VR Little Endian' \
  --edition "$EDITION"

An encoding explanation contains a summary, structured facts, optional bounded text excerpt, references, and explanatory evidence classification.

Use this after the structured lookup when a human-readable explanation is needed. Do not treat the explanation as a new independently parsed normative rule.

Recommended workflow

1. Resolve the transfer syntax by UID or keyword.
2. Inspect its structured encoding fields and retirement state.
3. Follow the returned references.
4. Request an encoding explanation only when prose is useful.
5. Fall back to general cited text search when the specialized resolver does not cover the topic.
6. Preserve warnings and null fields in downstream code.

Agent-routing example

For a transfer-syntax question, call dicom_lookup_transfer_syntax first.
Call dicom_explain_encoding_rule only to add a cited explanation. Do not infer
encoding properties that are null or absent from the structured result.

See MCP tools for matching tool arguments and Structured lookup and text fallback for the evidence hierarchy.