Eval runs

Mint a model lease for MCPJam-hosted inference

How an SDK eval running OUTSIDE the platform (local dev, CI) uses MCPJam-hosted inference on the organization’s credits, with no provider key of its own. Authenticate like any other /api/v1 route (typically an sk_ key).

The lease is strictly narrower than the key used to get it: one organization, one project, one model, one proxy host, about 30 minutes, a per-lease spend and call cap, and revocable by runId.

The {projectId} segment declares which project’s organization pays, and always wins over any projectId in the body. The literal default resolves to the key org’s Default project — the zero-config CI case, and the same resolution the eval-ingest routes use, so a lease and the results it produces land in the same project.

POST

projects

{projectId}

model-leases

Mint a model lease for MCPJam-hosted inference

curl --request POST \
  --url https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "anthropic/claude-sonnet-4.5",
  "runId": "<string>",
  "maxOutputTokens": 123
}
'

import requests

url = "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases"

payload = {
    "model": "anthropic/claude-sonnet-4.5",
    "runId": "<string>",
    "maxOutputTokens": 123
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({model: 'anthropic/claude-sonnet-4.5', runId: '<string>', maxOutputTokens: 123})
};

fetch('https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'anthropic/claude-sonnet-4.5',
    'runId' => '<string>',
    'maxOutputTokens' => 123
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases"

	payload := strings.NewReader("{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}"

response = http.request(request)
puts response.read_body

{
  "lease": "<string>",
  "protocol": "anthropic",
  "proxyBaseUrl": "<string>",
  "expiresAt": 123,
  "runId": "<string>",
  "model": "<string>"
}

Authorizations

Authorization

string

header

required

MCPJam API key (sk_…). Create one at Settings → API keys. Guest sessions cannot use the API, and API keys cannot manage other API keys.

Path Parameters

projectId

string

required

Project id, or the literal default for the key org's Default project.

Body

application/json

model

string

required

Canonical model id. Only anthropic/claude-* and openai/gpt-5* are served, and only if the model has a gateway pricing row.

Example:

"anthropic/claude-sonnet-4.5"

runId

string

Caller-chosen id to revoke by. Generated if omitted.

maxOutputTokens

integer

Per-call output ceiling, clamped to the server maximum.

Response

A short-lived lease and the proxy to present it to.

lease

string

required

Present it as the x-mcpjam-harness-lease header on requests to proxyBaseUrl. Never as a bearer token, and never sent to any other host.

protocol

enum<string>

required

Which vendor wire format proxyBaseUrl speaks, derived from the model's vendor prefix.

Available options:

anthropic,

openai

proxyBaseUrl

string<uri>

required

Base URL for the metered model proxy. Anthropic leases accept POST /v1/messages; OpenAI leases accept POST /v1/responses.

expiresAt

integer

required

Epoch milliseconds. Mint a new lease before this; the proxy fails an expired one closed.

runId

string

required

Pass to the revoke operation to kill this lease early.

model

string

required

⌘I

Mint a model lease for MCPJam-hosted inference

curl --request POST \
  --url https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "anthropic/claude-sonnet-4.5",
  "runId": "<string>",
  "maxOutputTokens": 123
}
'

import requests

url = "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases"

payload = {
    "model": "anthropic/claude-sonnet-4.5",
    "runId": "<string>",
    "maxOutputTokens": 123
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({model: 'anthropic/claude-sonnet-4.5', runId: '<string>', maxOutputTokens: 123})
};

fetch('https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'anthropic/claude-sonnet-4.5',
    'runId' => '<string>',
    'maxOutputTokens' => 123
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases"

	payload := strings.NewReader("{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.mcpjam.com/api/v1/projects/{projectId}/model-leases")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"anthropic/claude-sonnet-4.5\",\n  \"runId\": \"<string>\",\n  \"maxOutputTokens\": 123\n}"

response = http.request(request)
puts response.read_body

{
  "lease": "<string>",
  "protocol": "anthropic",
  "proxyBaseUrl": "<string>",
  "expiresAt": 123,
  "runId": "<string>",
  "model": "<string>"
}

API Guides

Endpoints

Mint a model lease for MCPJam-hosted inference

Authorizations

Path Parameters

Body

Response