PCB Design Rule Editing (DRC)

Inspect native PCB design rules, create named rule profiles, and update active board rules through a two-phase Prepare → Approve → Confirm → Readback workflow.

Version Requirement

Requires MCP server >= 1.1.0, extension >= 0.2.0, and an active PCB tab (documentType: 3) in EasyEDA Pro. See Upgrading & Compatibility.

Two-Phase Edit Workflow

sequenceDiagram
    participant U as Human
    participant A as AI Client
    participant S as MCP Server
    participant E as EasyEDA Extension (eda.pcb_Drc)

    A->>S: 1. easyeda_get_drc_rules({ scope: "current" })
    S->>E: getDrcRules
    E-->>A: Raw rule JSON + target identity + capabilities
    A->>S: 2. easyeda_prepare_drc_edit({ operation })
    S->>E: prepareDrcEdit (no write)
    E-->>A: editId + preview (before, requestedAfter, changedKeys)
    A->>U: 3. Show preview & ask approval for editId
    U-->>A: Approve editId
    A->>S: 4. easyeda_confirmed_action({ action: "editDrcRules", params: { editId }, confirmation })
    S->>E: Verify target/rules unchanged -> write -> native readback
    E-->>A: status: "applied" (documentSaved: false)

Supported Operations

Pass one operation to easyeda_prepare_drc_edit:

operation.type	Payload Fields	Scope & Effect
createConfiguration	configurationName: string, config: object	saved_rule_configuration — Creates a new named rule profile with allowOverwrite: false (never overwrites existing/system profiles).
updateCurrentConfiguration	config: object	active_pcb — Replaces the active PCB's rule configuration ({ name, config }.config).
replaceNetRules	rules: object[]	active_pcb — Replaces the entire per-net rule table ([] clears the table).
replaceNetByNetRules	rules: object	active_pcb — Replaces the net-by-net rule object keyed by category ({} clears categories).
replaceRegionRules	rules: object[]	active_pcb — Replaces the entire region rule table ([] clears the table).

Preserving Editor Units & Structure

easyeda_get_drc_rules with scope: "current" returns { name, config } using the editor's native structure and units (mm or mil). When calling createConfiguration or updateCurrentConfiguration, copy the inner config object, modify the desired fields, and pass config (not the { name, config } wrapper).

Example Payloads

1. Prepare Profile Creation

{
  "operation": {
    "type": "createConfiguration",
    "configurationName": "JLCPCB-2Layer-0.15mm",
    "config": {
      "Safe Spacing": {},
      "Track": {},
      "Via Size": {}
    }
  }
}

2. Confirm Prepared Edit

{
  "action": "editDrcRules",
  "params": {
    "editId": "bd549553-e96d-4c9b-bb1f-f8e8ac28cf89"
  },
  "confirmation": "CONFIRM editDrcRules bd549553-e96d-4c9b-bb1f-f8e8ac28cf89"
}

Safety Guarantees & Error Recovery

• Dual confirmation gate: Both the MCP server and the browser extension verify CONFIRM editDrcRules <editId> before touching eda.pcb_Drc.
• Stale-state protection: Before writing, the extension re-verifies the PCB documentId, projectId, tabId, WebSocket session generation, and current rule state. Any change returns stale_edit without writing.
• Expiration & single execution: Previews expire after 15 minutes (edit_expired) and can only be executed once (edit_already_started).
• Full readback verification: An edit is marked applied only if eda.pcb_Drc returns true and a subsequent native readback matches the requested JSON.
• Explicit PCB save: Applying DRC rules sets documentSaved: false. Saving the PCB requires a separate easyeda_confirmed_action (action: "save").

Handling Timeouts (drc_edit_outcome_unknown)

If the WebSocket times out or disconnects after a DRC write was dispatched, the server returns error: "drc_edit_outcome_unknown" with retryable: false. Never automatically replay the mutation. Call easyeda_get_drc_edit_result with the same editId to check whether the write completed.

Official EasyEDA Pro API References

• PCB_Drc · saveRuleConfiguration · overwriteCurrentRuleConfiguration
• overwriteNetRules · overwriteNetByNetRules · overwriteRegionRules
• EDMT_EditorDocumentType (PCB = 3, SCHEMATIC_PAGE = 1, SYMBOL = 2, FOOTPRINT = 4)