remove

name	remove
description	Remove elements from a threat model with dependency checking
agent	threat-modeler
argument-hint	[element reference]

Remove elements from a Dethernety threat model with dependency checking.

Steps

1. Resolve Model

Use the Model Resolution Protocol to identify the target model. Read current model files from disk (structure.json, dataflows.json, data-items.json).

2. Identify Element

From $ARGUMENTS or conversation, identify the element to remove. Match by name (case-insensitive) or by ID.

If ambiguous (e.g., multiple components named "API Server"), list all matches and ask the user to specify:

Found 2 matches for "API Server":
  1. [PROCESS] API Server — in DMZ boundary
  2. [PROCESS] API Server — in Internal Network boundary
Which one? (1 or 2)

3. Check Dependencies

Before removal, scan for elements that depend on the target:

Component dependencies:

• Data flows where this component is source or target
• Data items associated with those flows
• Attribute file at attributes/components/<id>.json

Boundary dependencies:

• Child components within this boundary
• Child sub-boundaries
• Data flows that cross this boundary

Data flow dependencies:

• Data items attached to this flow
• Attribute file at attributes/dataFlows/<id>.json

Data item dependencies:

• Attribute file at attributes/dataItems/<id>.json

4. Show Dependencies and Confirm

Crown-jewel pre-check. Before drafting the dependency table, check whether the element is tagged as a crown jewel. For a component, that is crownJewel === true on the component in structure.json. For a non-component element (data flow / data item / boundary), it is crown_jewel === true in its attribute bag (attributes/<kind>/<id>.json, top-level or nested attributes.crown_jewel — a local-only mark). If tagged, elevate the prompt:

Removing [STORE] "Customer DB" — this element is tagged as a CROWN JEWEL.

Removing it from the model means the threat-modeling output will no
longer treat it as a security-critical asset. Confirm only if the asset
has genuinely been retired or relocated, not because it became
inconvenient to model.

Proceed? (yes / no)

If the user declines on the crown-jewel prompt, stop without showing dependencies — the safety prompt is the gate. If the user accepts (or the element is untagged), continue with the dependency table below. The dependency-removal cascade still applies for tagged elements once the crown-jewel prompt is accepted.

If dependencies exist, show them before proceeding:

Removing [PROCESS] "API Server" will also affect:

  Data flows (will be removed):
    - "Client → API Server" (HTTP requests)
    - "API Server → Database" (SQL queries)
    - "API Server → Redis" (Cache lookups)

  Data items (orphaned — flows removed):
    - "User Credentials" on "Client → API Server"

  Attribute files (will be deleted):
    - attributes/components/abc123.json

Proceed? (yes / no / remove component only)

• yes — remove the element and all dependent elements
• no — cancel
• remove component only — remove the component but leave flows (they become orphaned and are flagged for review)

If no dependencies exist, confirm with a simpler prompt:

Remove [STORE] "Redis Cache" from Data Tier? (yes / no)

5. Remove Element

Remove from the appropriate model file:

• structure.json for components and boundaries
• dataflows.json for data flows
• data-items.json for data items

Delete associated attribute files from the attributes/ directory.

If removing a boundary, relocate orphaned child components to the parent boundary (don't delete them silently).

6. Handle State Regression

If the model is at ENRICHING or later state, a structural change triggers backward transition:

1. Revert currentState to STRUCTURE_COMPLETE in .dethereal/state.json
2. Delete .dethereal/quality.json (forces recomputation)
3. Clear model_signed_off from state.json if present
4. Remove deleted element IDs from staleElements[] if present. If dependent elements were modified (e.g., orphaned flows reconnected, child components relocated), add those modified element IDs to staleElements[]
5. Warn the user: "Removing elements reverted state from [previous] to STRUCTURE_COMPLETE."

7. Validate and Footer

Call mcp__plugin_dethereal_dethereal__validate_model_json to check structural validity after removal.

[done] Removed [PROCESS] "API Server" and 3 dependent data flows. Quality: X/100.
[next] /dethereal:view (review updated model) or /dethereal:add (add replacements)