Erd

Generate or update Mermaid Entity-Relationship Diagrams from Salesforce object metadata. Reads .object-meta.xml files plus their field-meta.xml subdirectories, extracts relationships (Lookup, MasterDetail, Hierarchy), and emits a Mermaid ERD as Markdown. Useful for design reviews and onboarding.From its SKILL.md

Install

npx -y skills add vhmarquez/argo --skill erd

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

1 stars1 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

SKILL.md

5.2 KB, as published. Nobody here has run it

You are generating an ERD from local source metadata. You read the project's .object-meta.xml files and the per-field metadata under each object's fields/ directory, extract relationships, and emit one or more Mermaid erDiagram blocks.

Read Project Config First

source "${CLAUDE_PLUGIN_ROOT}/hooks/lib/config.sh"
APEX_SRC="$(sf_config_get '.paths.apexSource' "$ENV")"
# Objects live under <packageDir>/main/default/objects — derive from sfdx-project.json
# or accept --objects-path override.

Input

$ARGUMENTS:

(empty) — diagram every custom object + selected standard objects (Account, Contact, Case, Opportunity, Lead, User) where they're referenced by a custom object
<Object> — diagram one object's neighborhood (the object + everything it references and that references it, depth 1)
--depth <n> — relationship depth from the seed (default 1)
--scope custom|all — restrict to custom (default), or include all standard
--out <path> — output Markdown file (default docs/diagrams/erd.md; overwrites)
--objects-path <path> — override the default force-app/main/default/objects location

Steps

1. Discover objects in source

OBJECTS_PATH="${OBJECTS_PATH:-force-app/main/default/objects}"
[[ -d "$OBJECTS_PATH" ]] || { echo "[erd] objects path not found: $OBJECTS_PATH" >&2; exit 2; }
ls -1 "$OBJECTS_PATH"

2. Parse each object

For every directory under OBJECTS_PATH:

Read <Object>.object-meta.xml for label and shareability
Read each <Object>/fields/*.field-meta.xml for:
- <fullName> — field API name
- <type> — Lookup, MasterDetail, Hierarchy, plus regular types
- <referenceTo> — target object (only for Lookup / MasterDetail / Hierarchy)
- <required> — required flag
- <deleteConstraint> — Restrict / SetNull / Cascade

Build an in-memory model:

{
  "objects": {
    "Order__c": {
      "label": "Order",
      "fields": [{"name": "Customer__c", "type": "Lookup", "referenceTo": "Account", "required": true}]
    }
  }
}

3. Compute the diagram scope

If a seed object was given, walk relationships up to --depth and collect the closure. Otherwise include all custom objects.

4. Emit Mermaid

erDiagram
  Account ||--o{ Order__c : "Customer__c"
  Order__c ||--|{ Order_Item__c : "Order__c (master-detail)"
  Order_Item__c }o--|| Product2 : "Product__c"
  Order__c {
    string Name
    picklist Status__c
    currency Total_Amount__c
  }
  Order_Item__c {
    string Name
    number Quantity__c
    currency Unit_Price__c
    masterdetail Order__c
    lookup Product__c
  }

Cardinality rules (Mermaid erDiagram):

||--o{ — one-to-many, optional on the many side
||--|{ — one-to-many, required (master-detail with required)
}o--|| — many-to-one with required parent (lookup required)
}o--o| — optional both sides (rare)

5. Wrap in Markdown

# Entity-Relationship Diagram: <project.name>

Generated: 2026-04-28T11:30:00Z (`/argo:erd`)
Source: force-app/main/default/objects (27 custom + 4 standard referenced)
Depth from seed: <n> | Seed: <Object> or "(all custom)"

## Diagram

```mermaid
erDiagram
  ...

Object Index

Object	Custom	OWD	Fields	Relationships
Order__c	✅	Private	14	Lookup → Account, MD ← Order_Item__c
...


### 6. Output

Write to `--out` (default `docs/diagrams/erd.md`); create the directory if needed. Print a one-line summary on stdout: `[erd] Wrote 1 diagram with 12 objects to docs/diagrams/erd.md`.

CI mode: emit the JSON model on stdout, no Markdown side-effect.

### 7. Exit codes
- 0 — diagram emitted (or empty if no objects matched)
- 2 — input/path error

## Rules

- **Standard objects only when referenced.** Don't emit a node for `User` unless a custom object lookups to it. Reduces clutter
- **Honor master-detail visualization.** Use `||--|{` for required master-detail; the strong line communicates the cascade-delete semantic
- **Skip `OwnerId`, `CreatedById`, `LastModifiedById`** by default — they're noise on every diagram. `--include-system-fields` to opt in
- **Field labels**: show the API name + a short type marker (`string`, `picklist`, `number`, etc.) — full descriptions belong in the docs/apex-classes generated docs, not the ERD
- **Hierarchical fields** (`ParentId` on Account) — render as a self-loop with cardinality `||--o{`
- **Idempotent.** Re-running on the same source must produce the same Markdown bit-for-bit so `git diff` is meaningful

## Consumers

- `@architect` and `@data-architect` reference the latest ERD when designing changes
- `/argo:generate-docs` may include a snippet of the ERD in `docs/README.md`
- Visualizers: GitHub renders Mermaid in Markdown natively; VS Code with the Mermaid Preview extension; or paste into mermaid.live