# Understudy docs full export

> Docs for the Understudy LLM gateway, control plane, capture pipeline, routing, managed models, Desktop, and open-source agent tools.

Source: https://docs.understudylabs.com
Compact map: https://docs.understudylabs.com/llms.txt

## Product summary

Understudy is a gateway for production LLM traffic. It is a drop-in replacement for Anthropic and OpenAI API endpoints that can forward requests, capture request/response evidence by project and workload, and route measured slices of traffic to managed model supply. The docs also cover the dashboard-backed control plane, Understudy Desktop, portable local task models, and the MIT-licensed agent tools that help coding agents collect evidence and run optimization loops locally.

## Canonical routes

- https://docs.understudylabs.com
- https://docs.understudylabs.com/quickstart
- https://docs.understudylabs.com/workspace
- https://docs.understudylabs.com/authentication
- https://docs.understudylabs.com/tutorials/first-captured-request
- https://docs.understudylabs.com/tutorials/replace-a-model
- https://docs.understudylabs.com/tutorials/build-an-eval-set
- https://docs.understudylabs.com/concepts/architecture
- https://docs.understudylabs.com/concepts/projects-and-workloads
- https://docs.understudylabs.com/concepts/modes
- https://docs.understudylabs.com/concepts/routing
- https://docs.understudylabs.com/concepts/capture
- https://docs.understudylabs.com/guides/route-a-workload
- https://docs.understudylabs.com/guides/scope-with-projects
- https://docs.understudylabs.com/guides/tag-requests
- https://docs.understudylabs.com/reference/proxy-endpoints
- https://docs.understudylabs.com/reference/request-headers
- https://docs.understudylabs.com/reference/response-headers
- https://docs.understudylabs.com/reference/errors
- https://docs.understudylabs.com/reference/control-plane
- https://docs.understudylabs.com/reference/control-plane/keys
- https://docs.understudylabs.com/reference/control-plane/projects
- https://docs.understudylabs.com/reference/control-plane/workloads-routing
- https://docs.understudylabs.com/reference/control-plane/captures
- https://docs.understudylabs.com/reference/control-plane/evaluations
- https://docs.understudylabs.com/reference/control-plane/reporting
- https://docs.understudylabs.com/open-source/agent-tools
- https://docs.understudylabs.com/open-source/cli
- https://docs.understudylabs.com/open-source/desktop-task-models
- https://docs.understudylabs.com/open-source/task-model-format

## Getting started

### Introduction

URL: https://docs.understudylabs.com
Summary: What Understudy is, what the gateway does, and how these docs are organized.
Use this page when you need the overall product model and reading order.

### Quickstart

URL: https://docs.understudylabs.com/quickstart
Summary: From an sk_* key to a captured request in five minutes — both connection paths.
Use this page when you need the first gateway request or SDK setup.

### Your workspace

URL: https://docs.understudylabs.com/workspace
Summary: What signup creates for you, and a map of the dashboard's pages.
Use this page when you need what signup creates and where dashboard pages live.

### Authentication

URL: https://docs.understudylabs.com/authentication
Summary: Understudy keys: how to send them, where they work, how to manage them.
Use this page when you need credential placement and auth behavior.

## Tutorials

### First captured request

URL: https://docs.understudylabs.com/tutorials/first-captured-request
Summary: Zero to a recorded request/response pair you can read in the dashboard.
Use this page when you need a step-by-step workflow from setup through captures and replacement.

### Replace a model on live traffic

URL: https://docs.understudylabs.com/tutorials/replace-a-model
Summary: The whole loop: isolate a call site, baseline it, route 5%, compare, ratchet.
Use this page when you need a step-by-step workflow from setup through captures and replacement.

### Build an eval set from captures

URL: https://docs.understudylabs.com/tutorials/build-an-eval-set
Summary: Use tags and sampling so the captures you collect become a dataset, not a pile.
Use this page when you need a step-by-step workflow from setup through captures and replacement.

## Concepts

### Architecture

URL: https://docs.understudylabs.com/concepts/architecture
Summary: The data plane, the control plane, and the five-phase request pipeline.
Use this page when you need the mental model behind gateway behavior.

### Projects & workloads

URL: https://docs.understudylabs.com/concepts/projects-and-workloads
Summary: The two-level scoping model that organizes traffic, captures, and routing.
Use this page when you need the mental model behind gateway behavior.

### Modes: BYO & managed

URL: https://docs.understudylabs.com/concepts/modes
Summary: Whose credential pays for the upstream call, and what each mode permits.
Use this page when you need the mental model behind gateway behavior.

### Routing

URL: https://docs.understudylabs.com/concepts/routing
Summary: Passthrough, model routes, traffic percentages, the catalog arm, and fallback.
Use this page when you need the mental model behind gateway behavior.

### Capture

URL: https://docs.understudylabs.com/concepts/capture
Summary: What the gateway records, how sampling works, and what the envelope contains.
Use this page when you need the mental model behind gateway behavior.

## Guides

### Route a workload

URL: https://docs.understudylabs.com/guides/route-a-workload
Summary: Shift a slice of live traffic onto a managed model, verify, and ratchet up.
Use this page when you need operational instructions for a specific production workflow.

### Scope with projects

URL: https://docs.understudylabs.com/guides/scope-with-projects
Summary: Keep environments and product surfaces isolated using scoping headers.
Use this page when you need operational instructions for a specific production workflow.

### Tag requests

URL: https://docs.understudylabs.com/guides/tag-requests
Summary: Attach your own dimensions to captures with x-understudy-tags.
Use this page when you need operational instructions for a specific production workflow.

## Gateway API

### Proxy endpoints

URL: https://docs.understudylabs.com/reference/proxy-endpoints
Summary: The OpenAI- and Anthropic-compatible surface at api.understudylabs.com.
Use this page when you need gateway API contracts, headers, endpoints, or errors.

### Request headers

URL: https://docs.understudylabs.com/reference/request-headers
Summary: Every x-understudy-* header you can send, with limits.
Use this page when you need gateway API contracts, headers, endpoints, or errors.

### Response headers

URL: https://docs.understudylabs.com/reference/response-headers
Summary: The legibility headers that tell you how each request resolved.
Use this page when you need gateway API contracts, headers, endpoints, or errors.

### Errors

URL: https://docs.understudylabs.com/reference/errors
Summary: The error envelope and every error type the gateway returns.
Use this page when you need gateway API contracts, headers, endpoints, or errors.

## Control plane API

### Overview

URL: https://docs.understudylabs.com/reference/control-plane
Summary: Auth, conventions, and the path families behind the dashboard and the CLI.
Use this page when you need dashboard-backed API routes and response shapes.

### API keys

URL: https://docs.understudylabs.com/reference/control-plane/keys
Summary: List, create, and revoke sk_* keys programmatically.
Use this page when you need dashboard-backed API routes and response shapes.

### Projects

URL: https://docs.understudylabs.com/reference/control-plane/projects
Summary: Create, list, rename, and soft-delete projects; ensure the default.
Use this page when you need dashboard-backed API routes and response shapes.

### Workloads & routing

URL: https://docs.understudylabs.com/reference/control-plane/workloads-routing
Summary: Workload CRUD, the model catalog, and the route write endpoints.
Use this page when you need dashboard-backed API routes and response shapes.

### Captures

URL: https://docs.understudylabs.com/reference/control-plane/captures
Summary: List capture objects and fetch a single envelope by request id.
Use this page when you need dashboard-backed API routes and response shapes.

### Evaluations & cohorts

URL: https://docs.understudylabs.com/reference/control-plane/evaluations
Summary: Select redacted workload captures, freeze a cohort, and materialize it locally with audited short-lived exports.
Use this page when you need dashboard-backed API routes and response shapes.

### Reporting & health

URL: https://docs.understudylabs.com/reference/control-plane/reporting
Summary: Routing status, provider health metrics, and compact status summary — self-service diagnostics.
Use this page when you need dashboard-backed API routes and response shapes.

## Open source

### Agent tools

URL: https://docs.understudylabs.com/open-source/agent-tools
Summary: The MIT-licensed local client: skills for coding agents plus a thin CLI.
Use this page when you need local agent tooling and CLI behavior.

### CLI reference

URL: https://docs.understudylabs.com/open-source/cli
Summary: Every understudy command in the public CLI, with the first hosted journey.
Use this page when you need local agent tooling and CLI behavior.

### Desktop & local task models

URL: https://docs.understudylabs.com/open-source/desktop-task-models
Summary: Install a portable classifier, satisfy its base-model dependency, and test new examples locally.
Use this page when you need local agent tooling and CLI behavior.

### .understudy-model format

URL: https://docs.understudylabs.com/open-source/task-model-format
Summary: The versioned manifest, files, integrity rules, and runtime contract for portable task models.
Use this page when you need local agent tooling and CLI behavior.

## API hosts

- Gateway data plane: https://api.understudylabs.com
- Dashboard and control plane UI: https://app.understudylabs.com
- Docs: https://docs.understudylabs.com

## Authentication summary

Use an Understudy sk_* key for gateway traffic, control-plane API calls, and the agent CLI. Anthropic-shaped requests can send the Understudy key in x-api-key. OpenAI-shaped requests use Authorization: Bearer. Bring-your-own-provider-key requests attach the provider credential in x-understudy-upstream-key for that single upstream call.