c2pa-kg

name	c2pa-kg
description	Query the C2PA specification knowledge graph. Use when: implementing C2PA, checking spec requirements, looking up entity definitions, finding validation rules, comparing spec versions, or answering questions about C2PA data structures. TRIGGER when: user asks about C2PA entities, manifests, claims, assertions, ingredients, validation, trust model, or spec changes between versions.
argument-hint	[query or entity name, e.g. 'ClaimMap properties' or 'diff 2.2 2.4']
allowed-tools	Read, Bash, Glob, Grep, Agent

C2PA Knowledge Graph Query

You have access to a machine-readable knowledge graph derived from the C2PA specification. Use it to answer questions about C2PA data structures, validation rules, and version changes with precision rather than relying on training data.

Data sources

The knowledge graph is generated from the C2PA specs-core repository and stored as JSON artifacts. Check for pre-generated artifacts in this order:

1. MCP tools (if c2pa-knowledge-graph MCP server is running): use query_entity, query_validation_rules, diff_versions, or search_entities tools directly.
2. Local artifacts: look for output/<version>/metadata.json in the c2pa-knowledge-graph repo directory. If found, read and parse the JSON.
3. Generate on demand: if no artifacts exist and the user has specs-core cloned locally, run uv run c2pa-kg generate --spec-source <path> --version <version> --output-dir ./output.

How to answer queries

Entity lookup

When asked about a C2PA entity (e.g., "what properties does a Claim have?"):

1. Load metadata.json for the requested version (default: latest, currently 2.4).
2. Look up the entity in the entities dict. Entity names are CamelCase (e.g., ClaimMap, ClaimMapV2, ActionItemsMap, IngredientMapV3).
3. Report the entity's properties (name, type, required, cardinality, description), relationships (target entity, relationship type), and whether it is deprecated.
4. If the entity name is ambiguous, search across all entity names and suggest matches.

Validation rules

When asked about validation requirements:

1. Load validation rules from metadata.json -> validation_rules.
2. Filter by phase if specified: structural, cryptographic, trust, semantic, assertion, ingredient, timestamp, signature, content.
3. Report rules with their severity (must/shall/should/may), description, and referenced entities.
4. Cross-reference with status codes from status_codes when relevant.

Version comparison

When asked "what changed between X and Y":

1. Load metadata.json for both versions.
2. Compare entity sets: report added, removed, and modified entities.
3. For modified entities, compare properties: added/removed/changed fields.
4. Compare validation rule sets: added and removed rules.
5. Compare enum types: added/removed values.

Search

When the user's question is open-ended:

1. Search entity names and descriptions for keyword matches (case-insensitive).
2. Search validation rule descriptions for the query terms.
3. Report matching entities and rules with their definitions.

Known spec versions

Version	Date	Tag
2.4	2026-04-01	2.4
2.3	2025-12-01	38e492b0 (tag missing upstream)
2.2	2025-09-22	2.2
2.1	2024-09-26	2.1
2.0	2024-01-24	2.0
1.4	2023-11-06	1.4
1.3	2023-03-30	1.3
1.2	2022-11-15	1.2
1.1	2022-09-12	1.1
1.0	2021-12-24	1.0
0.8	2021-11-11	0.8
0.7	2021-09-12	0.7

Version 2.3 (December 2025) covers live video and unstructured text. The upstream c2pa-org/specs-core repo is missing the 2.3 tag due to a process gap; this tool targets the merge commit 38e492b0 directly.

Output format

• Report entity definitions as structured tables (name, type, required, description).
• Report validation rules grouped by phase with severity indicators.
• Report version diffs as categorized lists (added, removed, modified).
• Always cite the spec version number in your response.
• Use precise C2PA terminology: manifests, claims, assertions, ingredients, trust anchors.

Critical distinction

C2PA (the standard) defines document-level provenance. Entity definitions in this knowledge graph describe the C2PA standard's data structures. Do not confuse C2PA standard capabilities with any proprietary extensions built on top of C2PA.