---
title: "Changes to Read Chart Preview"
method: POST
path: "/api/v1/charts/preview"
---

# Changes to Read Chart Preview

`POST /api/v1/charts/preview`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 1 of 77 revisions.

- **2026-10-16** `1a8ee9358d81`: 30 breaking, 7 info

## Changes

- **2026-10-16** `1a8ee9358d81`: 30 breaking, 7 info
  - removed the enum value `completion_cost` of the request property `chart/series/items/metric`
  - removed the enum value `completion_tokens` of the request property `chart/series/items/metric`
  - removed the enum value `completion_tokens_p50` of the request property `chart/series/items/metric`
  - removed the enum value `completion_tokens_p99` of the request property `chart/series/items/metric`
  - removed the enum value `cost_p50` of the request property `chart/series/items/metric`
  - removed the enum value `cost_p99` of the request property `chart/series/items/metric`
  - removed the enum value `error_rate` of the request property `chart/series/items/metric`
  - removed the enum value `feedback` of the request property `chart/series/items/metric`
  - removed the enum value `feedback_score_avg` of the request property `chart/series/items/metric`
  - removed the enum value `feedback_values` of the request property `chart/series/items/metric`
  - removed the enum value `first_token_p50` of the request property `chart/series/items/metric`
  - removed the enum value `first_token_p99` of the request property `chart/series/items/metric`
  - removed the enum value `latency_avg` of the request property `chart/series/items/metric`
  - removed the enum value `latency_p50` of the request property `chart/series/items/metric`
  - removed the enum value `latency_p99` of the request property `chart/series/items/metric`
  - removed the enum value `median_tokens` of the request property `chart/series/items/metric`
  - removed the enum value `prompt_cost` of the request property `chart/series/items/metric`
  - removed the enum value `prompt_tokens` of the request property `chart/series/items/metric`
  - removed the enum value `prompt_tokens_p50` of the request property `chart/series/items/metric`
  - removed the enum value `prompt_tokens_p99` of the request property `chart/series/items/metric`
  - removed the enum value `run_count` of the request property `chart/series/items/metric`
  - removed the enum value `streaming_rate` of the request property `chart/series/items/metric`
  - removed the enum value `tokens_p99` of the request property `chart/series/items/metric`
  - removed the enum value `total_cost` of the request property `chart/series/items/metric`
  - removed the enum value `total_tokens` of the request property `chart/series/items/metric`
  - the `chart/series/items/metric` request property type changed from `string` to no type
  - the `detail/items/` response's property type changed from `object` to `string` for status `422`
  - removed the required property `detail/items/loc` from the response with the `422` status
  - removed the required property `detail/items/msg` from the response with the `422` status
  - removed the required property `detail/items/type` from the response with the `422` status
  - added the new optional request property `chart/series/items/filter_definition`
  - added the new optional request property `chart/series/items/group_by_definitions`
  - added the new optional request property `chart/series/items/metadata`
  - added the new optional request property `chart/series/items/metric_definition`
  - added `#/components/schemas/CustomChartMetric, subschema #2` to the `chart/series/items/metric` request property `anyOf` list
  - the request property `chart/series/items/metric` became optional
  - added the new `run_queue_wait_time` enum value to the request property `chart/series/items/project_metric/anyOf[subschema #1: HostProjectChartMetric]/`

---

[Operation](https://skmtc.dev/langchain-ai/apis/langsmith/docs/api/v1/charts/preview/post.md) - [API](https://skmtc.dev/langchain-ai/apis/langsmith.md) - [Page](https://skmtc.dev/langchain-ai/apis/langsmith/changes/api/v1/charts/preview/post)