Devre

Studio concept by Minimolo

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Agents read freely. Writes wait for you.

Devre puts a switch in the circuit between an agent and its tools. Checking stock and drafting a reorder run on their own. The one call that changes the ledger stops at the gate until a person approves the exact payload.

Local deterministic simulation: inventory, no external system, no real orders.

Open the console
Devre tool circuit The agent connects through one bus to four tools. read_stock, draft_reorder and request_approval are wired straight through. commit_reorder sits behind a switch that closes only when a person approves. delete_item has no route and is denied. agent studio-supply waiting for you read_stock read / allow called draft_reorder draft / allow called request_approval draft / allow called approval gate commit_reorder write / require approval held at gate delete_item not on allowlist / deny no route Devre tool circuit The agent connects through one bus to four tools. read_stock, draft_reorder and request_approval are wired straight through. commit_reorder sits behind a switch that closes only when a person approves. delete_item has no route and is denied. agent studio-supply waiting for you read_stock read / allow called draft_reorder draft / allow called request_approval draft / allow called approval gate commit_reorder write / approval held at gate delete_item not on allowlist no route
Call allowed Write held, switch open Blocked or rejected

Studio supply-room console

Six supply-room items. Pick a scenario, then step the agent through its tool calls and decide the write yourself.

Scenarios

  • A. Check paper levelsOnly read tools run.
  • B. Restock low itemsRead, draft, request approval, then the write stops at the gate.
  • C. Clear old stockThe agent asks for delete_item; policy denies it.

The console needs scripts to run. Shown below: scenario B held at the gate.

Example: scenario B, step 4 of 4, commit_reorder held at the gate.

Approval gate

Gate open, write held

commit_reorder is held at the gate. Approving writes 4 lines to on order and moves the ledger to v2.

Lines starting with - show the current value. Lines starting with + show the value after approval.

{  "draft_id": "DR-0001",  "ledger_version": 1,  "on_order": {-   "SR-101": 0,+   "SR-101": 6,-   "SR-103": 0,+   "SR-103": 13,-   "SR-105": 0,+   "SR-105": 3,-   "SR-106": 0+   "SR-106": 6  }}

Supply-room ledger

Ledger v1

Supply-room stock. Rows below their reorder point are flagged. Only the on order column can change.
SKUItemOn handReorder pointOn orderStatus
SR-101A3 matte paper, pack of 250240Below point
SR-102Fineliner 0.3, box of 12960OK
SR-103Foam board 5 mm, sheet380Below point
SR-104Archival tape, roll540OK
SR-105Cutting mat A2120Below point
SR-106Test-print film, pack of 20030Below point

Trace

local Example run

Run 1: Restock low items

  1. 1read_stockreadallowed

    Request

    { "below_reorder_point": true }

    Response

    {
  "ledger_version": 1,
  "items": [
    { "sku": "SR-101", "on_hand": 2, "reorder_point": 4, "on_order": 0 },
    { "sku": "SR-103", "on_hand": 3, "reorder_point": 8, "on_order": 0 },
    { "sku": "SR-105", "on_hand": 1, "reorder_point": 2, "on_order": 0 },
    { "sku": "SR-106", "on_hand": 0, "reorder_point": 3, "on_order": 0 }
  ]
}
  2. 2draft_reorderdraftallowed

    Request

    {
  "rule": "top up to 2 x reorder point",
  "lines": [
    { "sku": "SR-101", "quantity": 6 },
    { "sku": "SR-103", "quantity": 13 },
    { "sku": "SR-105", "quantity": 3 },
    { "sku": "SR-106", "quantity": 6 }
  ]
}

    Response

    { "draft_id": "DR-0001", "lines": 4, "ledger_changed": false }
  3. 3request_approvaldraftallowed

    Request

    { "tool": "commit_reorder", "draft_id": "DR-0001" }

    Response

    { "approval_id": "AP-0001", "status": "pending" }
  4. 4commit_reorderwriteheld at gate

    Request

    {
  "draft_id": "DR-0001",
  "ledger_version": 1,
  "lines": [
    { "sku": "SR-101", "add_on_order": 6 },
    { "sku": "SR-103", "add_on_order": 13 },
    { "sku": "SR-105", "add_on_order": 3 },
    { "sku": "SR-106", "add_on_order": 6 }
  ]
}

    Response

    none: not executed until a person decides

Tool schemas

The four tools the agent can see, written as MCP-style definitions. The side-effect class decides which policy applies.

read_stockread 
{
  "name": "read_stock",
  "description": "Return supply-room rows. No side effects.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "category": {
        "type": "string",
        "enum": ["paper", "drawing", "modelling", "conservation"]
      },
      "below_reorder_point": { "type": "boolean" }
    },
    "additionalProperties": false
  },
  "sideEffect": "read"
}
draft_reorderdraft 
{
  "name": "draft_reorder",
  "description": "Build a reorder draft in memory. The ledger is not touched.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "rule": { "type": "string" },
      "lines": {
        "type": "array",
        "items": {
          "type": "object",
          "properties": {
            "sku": { "type": "string" },
            "quantity": { "type": "integer", "minimum": 1 }
          },
          "required": ["sku", "quantity"]
        }
      }
    },
    "required": ["lines"]
  },
  "sideEffect": "draft"
}
request_approvaldraft 
{
  "name": "request_approval",
  "description": "Open an approval for one exact write payload.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "tool": { "type": "string", "enum": ["commit_reorder"] },
      "draft_id": { "type": "string" }
    },
    "required": ["tool", "draft_id"]
  },
  "sideEffect": "draft"
}
commit_reorderwrite 
{
  "name": "commit_reorder",
  "description": "Add quantities to the on order column of the ledger. Runs only after a person approves the matching payload.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "draft_id": { "type": "string" },
      "ledger_version": { "type": "integer" },
      "lines": {
        "type": "array",
        "items": {
          "type": "object",
          "properties": {
            "sku": { "type": "string" },
            "add_on_order": { "type": "integer", "minimum": 1 }
          },
          "required": ["sku", "add_on_order"]
        }
      }
    },
    "required": ["draft_id", "ledger_version", "lines"]
  },
  "sideEffect": "write"
}

Policy

Each tool call is checked against this table before it runs.

ToolClassAllowRequire approvalDeny
read_stockreadYesNoNo
draft_reorderdraftYesNoNo
request_approvaldraftYesNoNo
commit_reorderwriteHeldYes, at gateNo
delete_itemnot declaredNoNoYes

delete_item has no schema. Any call to a tool outside the allowlist is denied before it reaches the gate, so there is nothing for a person to approve.

How the gate is built

  • Allowlist by side effect

    Every tool is declared as read, draft or write. Reads and drafts pass. Anything undeclared is denied.

  • Approval covers one payload

    The person sees the exact lines and ledger version that will be written. The next write needs its own approval.

  • Append-only trace

    Calls, decisions and responses are added in order and never edited. Reset clears the trace and the ledger together.

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