KARTA — spend control for AI agents
Task envelope, budget ledger, kill switch and signed receipts for agents that pay.
使うべきか
品質と安全性
ツール定義とプロトコルへの準拠に関する自動分析に基づいています。
コンテキストコスト
これは、サーバーのツールがモデルのコンテキストに読み込まれるたびに消費されるおおよそのトークン数です。数が多いほど、ほかのタスクに使える注意が減ります。
インストール
ワンクリックインストール
これを `claude_desktop_config.json` ファイルに追加してください:
{
"mcpServers": {
"guard": {
"url": "https://karta.rta.lat/mcp"
}
}
}リモートエンドポイント
https://karta.rta.lat/mcpstreamable-httpできること
ツール一覧
ツール（6）
🟢check_spend(envelope, amount, payee, calls_so_far, spent_so_far, ...)
Check whether a proposed agent spend is inside a task envelope. Returns verdict, rule, reason, counterfactual and next. No state is stored.
入力スキーマ
{
"type": "object",
"properties": {
"envelope": {
"additionalProperties": true,
"title": "Envelope",
"type": "object"
},
"amount": {
"title": "Amount",
"type": "string"
},
"payee": {
"title": "Payee",
"type": "string"
},
"calls_so_far": {
"default": 0,
"title": "Calls So Far",
"type": "integer"
},
"spent_so_far": {
"default": "0",
"title": "Spent So Far",
"type": "string"
},
"is_subscription": {
"default": false,
"title": "Is Subscription",
"type": "boolean"
}
},
"required": [
"envelope",
"amount",
"payee"
],
"title": "check_spendArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "check_spendOutput"
}🟡open_envelope(budget_total, per_call_max, calls_max, allowlist, allow_subscriptions, ...)
Create a signed budget envelope for one task: total budget, per-call cap, call count, allowlisted payees, subscription rule, expiry. Stores it in this server's local ledger (no funds move, no keys). Returns the envelope id. Capped at 30 envelopes/hour per server.
入力スキーマ
{
"type": "object",
"properties": {
"budget_total": {
"title": "Budget Total",
"type": "string"
},
"per_call_max": {
"title": "Per Call Max",
"type": "string"
},
"calls_max": {
"title": "Calls Max",
"type": "integer"
},
"allowlist": {
"anyOf": [
{
"items": {
"type": "string"
},
"type": "array"
},
{
"type": "null"
}
],
"default": null,
"title": "Allowlist"
},
"allow_subscriptions": {
"default": false,
"title": "Allow Subscriptions",
"type": "boolean"
},
"allow_new_payee": {
"default": false,
"title": "Allow New Payee",
"type": "boolean"
},
"approval_threshold": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
],
"default": null,
"title": "Approval Threshold"
},
"ttl_hours": {
"default": 24,
"title": "Ttl Hours",
"type": "integer"
}
},
"required": [
"budget_total",
"per_call_max",
"calls_max"
],
"title": "open_envelopeArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "open_envelopeOutput"
}🟢get_envelope(envelope_id)
Return an envelope's state: budget, per-call cap, calls used, spent, remaining, allowlist and expiry. Read-only.
入力スキーマ
{
"type": "object",
"properties": {
"envelope_id": {
"title": "Envelope Id",
"type": "string"
}
},
"required": [
"envelope_id"
],
"title": "get_envelopeArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "get_envelopeOutput"
}🔴kill_envelope(envelope_id, reason)
Stop one task envelope immediately: no further spend is approved for it, the reason is recorded with a timestamp. Idempotent — the first reason wins.
入力スキーマ
{
"type": "object",
"properties": {
"envelope_id": {
"title": "Envelope Id",
"type": "string"
},
"reason": {
"default": "owner stop",
"title": "Reason",
"type": "string"
}
},
"required": [
"envelope_id"
],
"title": "kill_envelopeArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "kill_envelopeOutput"
}🟢envelope_evidence(envelope_id)
Return an evidence bundle for one envelope: state, every recorded spend, the stop record and a sha256 of the whole pack that anyone can recompute. Read-only.
入力スキーマ
{
"type": "object",
"properties": {
"envelope_id": {
"title": "Envelope Id",
"type": "string"
}
},
"required": [
"envelope_id"
],
"title": "envelope_evidenceArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "envelope_evidenceOutput"
}🟢policy_rules
List the deterministic rules a spend is checked against (E01-E08) with the order they are applied and the meaning of each. Read-only, no state.
入力スキーマ
{
"type": "object",
"properties": {},
"title": "policy_rulesArguments"
}出力スキーマ
{
"type": "object",
"properties": {
"result": {
"title": "Result",
"type": "string"
}
},
"required": [
"result"
],
"title": "policy_rulesOutput"
}コミュニティ
エビデンス