---
title: "Get tool call histogram"
method: GET
path: "/v1/projects/{projectSlug}/tools/histogram"
tags: ["Tools"]
---

# Get tool call histogram

`GET /v1/projects/{projectSlug}/tools/histogram`

Returns per-bucket call counts over the range. Omit `toolName` to aggregate across every tool in the project; pass it to scope the histogram to a single tool.

## Path parameters

- `projectSlug` string, required — Project slug (human-readable identifier)

## Query parameters

- `fromIso` string, date-time — Lower bound (inclusive) of the time range. Defaults to 7 days before `toIso`.
- `toIso` string, date-time — Upper bound (inclusive) of the time range. Defaults to now.
- `toolName` string — Tool name. URL-encode names containing special characters.
- `bucketSeconds` integer — Bucket width in seconds. Derived from the range (~30 buckets) when omitted.
- `errorsOnly` 'true' | 'false' — When `true`, scope every aggregate to failed calls only.

## Response `200`

Call histogram

- ToolHistogramResponse
  - `items` ToolCallHistogramBucket[], required — Call buckets across the range, oldest first.
    - `bucketStart` string, required — ISO-8601 UTC timestamp of the bucket's start.
    - `calls` integer, required — Number of calls in this bucket.
    - `errors` integer, required — Number of errored calls in this bucket.
    - `p50DurationNs` number, required — Median call duration in this bucket, in nanoseconds.

## Other responses

- `400` — Validation error
- `401` — Unauthorized
- `404` — Not found

---

[API](https://skmtc.net/latitude-dev/apis/latitude.md) · [All operations](https://skmtc.net/latitude-dev/apis/latitude/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/latitude-dev/latitude/versions/6a8789c59a5c/schema)