Graph explanation artifacts

Composer can attach a small, interactive subgraph to a response by writing a JSON file with the .mgraph extension and citing it as an agent file:

@cite/agent_files/user@example.com/ran-hcc1937.mgraph

Selecting the citation hydrates any missing points, focuses their map, reveals the edges in rank order on the default WebGL map, and attaches the explanation to the focal point’s flashcard. Selecting it again or opening another citation clears the temporary overlay. It does not create or modify persisted map links.

Version 1

{
  "schema": "mantis.graphical-explanation/v1",
  "map_id": "map-uuid",
  "title": "RAN essentiality in HCC1937",
  "focal_point_id": "ran-idea-uuid",
  "links": [
    {
      "id": "ran-nemp2-attribution",
      "subject_idea_id": "ran-idea-uuid",
      "object_idea_id": "nemp2-idea-uuid",
      "predicate_name": "protein_protein_interaction",
      "description": "Top integrated-gradient attribution",
      "properties": {
        "integrated_gradient": 0.42,
        "pruning_delta": -0.18
      },
      "produced_by": "HIDRA",
      "display": {
        "rank": 1,
        "weight": 0.42
      }
    }
  ],
  "card": {
    "title": "Why RAN is essential in HCC1937",
    "summary": "The model relies on a nuclear-transport neighborhood.",
    "metrics": {
      "predicted_fitness": -3.21,
      "observed_fitness": -4.56
    },
    "caveats": [
      "This is a model attribution, not a causal mechanism."
    ]
  },
  "provenance": {
    "checkpoint": "abl_ESS_only_hero_v2/i1-s1-l1-a1-m1"
  }
}

Each entry in links uses the ordinary Mantis Link fields. The optional display object is artifact-only: rank controls reveal order and weight controls relative line width. point_ids may include unlinked contextual points. The client accepts at most 100 links, 200 total points, and a 2 MiB file.

The same projected SVG layer renders ordinary persisted Links when they are loaded for a hovered or selected point, bounded to 1,000 visible links. Dense points, picking, and LOD remain inside the custom WebGL renderer; sparse links and cards use its public world-to-screen projection.