Get a Session's context ledger

curl --request GET \
  --url https://api.checkfu.com/v1/sessions/{id}/ledger \
  --header 'Authorization: Bearer <token>' \
  --header 'checkfu-version: <checkfu-version>'

import requests

url = "https://api.checkfu.com/v1/sessions/{id}/ledger"

headers = {
    "checkfu-version": "<checkfu-version>",
    "Authorization": "Bearer <token>"
}

response = requests.get(url, headers=headers)

print(response.text)

const options = {
  method: 'GET',
  headers: {'checkfu-version': '<checkfu-version>', Authorization: 'Bearer <token>'}
};

fetch('https://api.checkfu.com/v1/sessions/{id}/ledger', 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://api.checkfu.com/v1/sessions/{id}/ledger",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "checkfu-version: <checkfu-version>"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://api.checkfu.com/v1/sessions/{id}/ledger"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("checkfu-version", "<checkfu-version>")
	req.Header.Add("Authorization", "Bearer <token>")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://api.checkfu.com/v1/sessions/{id}/ledger")
  .header("checkfu-version", "<checkfu-version>")
  .header("Authorization", "Bearer <token>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.checkfu.com/v1/sessions/{id}/ledger")

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

request = Net::HTTP::Get.new(url)
request["checkfu-version"] = '<checkfu-version>'
request["Authorization"] = 'Bearer <token>'

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

{
  "session_id": "<string>",
  "current_definition_version": 1,
  "current_context_tokens": 1,
  "cumulative_tokens": 1,
  "loaded_capabilities": [
    {
      "kind": "tool",
      "ref": "<string>"
    }
  ],
  "compactions": [
    {
      "event_id": "<string>",
      "seq": 1,
      "strategy": "native",
      "tokens_before": 1,
      "tokens_after": 1,
      "created_at": "<string>"
    }
  ],
  "last_event_seq": 1,
  "condensations": [
    {
      "event_id": "<string>",
      "seq": 1,
      "through_sequence": 1,
      "condensed_user_messages": 1,
      "condensed_agent_messages": 1,
      "created_at": "<string>"
    }
  ]
}

{
  "error": {
    "type": "validation.malformed",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-malformed"
  }
}

{
  "error": {
    "type": "auth.invalid_key",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-invalid-key"
  }
}

{
  "error": {
    "type": "auth.disabled_tenancy",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-disabled-tenancy"
  }
}

{
  "error": {
    "type": "validation.not_found",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-not-found"
  }
}

{
  "error": {
    "type": "budget.exceeded",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#budget-exceeded"
  }
}

{
  "error": {
    "type": "runtime.internal",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#runtime-internal"
  }
}

Get a Session's context ledger

Reads the Session’s context ledger: the admitted definition version, current_context_tokens (which follows compaction resets), never-decreasing cumulative_tokens, the loaded tool and skill capabilities by reference, every compaction, and each platform-authored condensation with the through_sequence it covered. It answers what is loaded and what it has cost, rather than what happened, and is derived from the authoritative event ledger on every read. It carries no prompts, messages, or argument content, so it is shareable where a transcript is not.

Checkfu support posture: alpha; hosted. Required evidence journey: session-turn. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities.

GET

sessions

{id}

ledger

Get a Session's context ledger

curl --request GET \
  --url https://api.checkfu.com/v1/sessions/{id}/ledger \
  --header 'Authorization: Bearer <token>' \
  --header 'checkfu-version: <checkfu-version>'

import requests

url = "https://api.checkfu.com/v1/sessions/{id}/ledger"

headers = {
    "checkfu-version": "<checkfu-version>",
    "Authorization": "Bearer <token>"
}

response = requests.get(url, headers=headers)

print(response.text)

const options = {
  method: 'GET',
  headers: {'checkfu-version': '<checkfu-version>', Authorization: 'Bearer <token>'}
};

fetch('https://api.checkfu.com/v1/sessions/{id}/ledger', 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://api.checkfu.com/v1/sessions/{id}/ledger",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "checkfu-version: <checkfu-version>"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://api.checkfu.com/v1/sessions/{id}/ledger"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("checkfu-version", "<checkfu-version>")
	req.Header.Add("Authorization", "Bearer <token>")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://api.checkfu.com/v1/sessions/{id}/ledger")
  .header("checkfu-version", "<checkfu-version>")
  .header("Authorization", "Bearer <token>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.checkfu.com/v1/sessions/{id}/ledger")

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

request = Net::HTTP::Get.new(url)
request["checkfu-version"] = '<checkfu-version>'
request["Authorization"] = 'Bearer <token>'

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

{
  "session_id": "<string>",
  "current_definition_version": 1,
  "current_context_tokens": 1,
  "cumulative_tokens": 1,
  "loaded_capabilities": [
    {
      "kind": "tool",
      "ref": "<string>"
    }
  ],
  "compactions": [
    {
      "event_id": "<string>",
      "seq": 1,
      "strategy": "native",
      "tokens_before": 1,
      "tokens_after": 1,
      "created_at": "<string>"
    }
  ],
  "last_event_seq": 1,
  "condensations": [
    {
      "event_id": "<string>",
      "seq": 1,
      "through_sequence": 1,
      "condensed_user_messages": 1,
      "condensed_agent_messages": 1,
      "created_at": "<string>"
    }
  ]
}

{
  "error": {
    "type": "validation.malformed",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-malformed"
  }
}

{
  "error": {
    "type": "auth.invalid_key",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-invalid-key"
  }
}

{
  "error": {
    "type": "auth.disabled_tenancy",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-disabled-tenancy"
  }
}

{
  "error": {
    "type": "validation.not_found",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-not-found"
  }
}

{
  "error": {
    "type": "budget.exceeded",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#budget-exceeded"
  }
}

{
  "error": {
    "type": "runtime.internal",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#runtime-internal"
  }
}

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

checkfu-version

enum<string>

required

Available options:

2026-08-27

Path Parameters

string

required

Pattern: ^sess_[0-9a-f]{32}$

Response

Success

session_id

string

required

Pattern: ^sess_[0-9a-f]{32}$

current_definition_version

integer | null

required

Required range: x > 0

current_context_tokens

integer

required

Required range: x >= 0

cumulative_tokens

integer

required

Required range: x >= 0

loaded_capabilities

object[]

required

Show child attributes

compactions

object[]

required

Show child attributes

last_event_seq

integer

required

Required range: x >= 0

condensations

object[]

Show child attributes

Developer tools

Canonical tables

Author protocols

Generated HTTP API

Get a Session's context ledger

Authorizations

Headers

Path Parameters

Response