Understudy Labs
Understudy Labs (YC S26) is an LLM gateway and model-optimization platform that helps teams move repeated production LLM workloads onto open-weight models they own. The Understudy gateway is a drop-in replacement for the Anthropic and OpenAI API endpoints that captures request/response traces by project and workload, routes measured slices of traffic to managed open models, and falls back safely. A REST control plane manages keys, projects, workloads, routing, captures, evaluation cohorts, and reporting, while the MIT-licensed understudy-agent-tools repo ships a CLI, a coding-agent skill library, a local MCP server, and Understudy Desktop with a documented loopback OpenAPI 3.1 contract.
Understudy Labs publishes 12 API contracts indexed on the APIs.io network, including Capabilities API, Conversations API, Downloads API, and 9 more. Tagged areas include Artificial Intelligence, LLM Gateway, Machine Learning, Open Source, and Model Routing.
The Understudy Labs catalog on APIs.io includes 1 Spectral governance ruleset.
Understudy Labs’ developer surface includes authentication, documentation, API reference, getting-started guide, support, engineering blog, CLI, and 22 more developer resources.
What this lets a business do 2
Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →
Kin Score
Markets this provider is in provisional
The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.
| Market | Position | Depth | Registered MCP server | Declares compatibility |
|---|---|---|---|---|
| Agent Skills (SKILL.md packages) | undeclared | - | - | 1 |
Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.
Standards implemented 4
Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.
APIs 12
Individual APIs this provider publishes, each with its own machine-readable definition.
Understudy Gateway API
Anthropic- and OpenAI-compatible LLM proxy at api.understudylabs.com. POST /v1/messages (Anthropic Messages), POST /v1/chat/completions (OpenAI Chat Completions), POST /v1/messa...
Understudy Control Plane API
REST surface behind the dashboard and CLI, served from the gateway host under /admin/v1 and /customer/v1, org-scoped and authenticated with sk_* bearer keys. Covers API key mint...
Understudy Labs Capabilities API
The Capabilities API from Understudy Labs — 1 operation(s) for capabilities.
Understudy Labs Conversations API
The Conversations API from Understudy Labs — 1 operation(s) for conversations.
Understudy Labs Downloads API
The Downloads API from Understudy Labs — 3 operation(s) for downloads.
Understudy Labs Feedback API
The Feedback API from Understudy Labs — 1 operation(s) for feedback.
Understudy Labs Metrics API
The Metrics API from Understudy Labs — 1 operation(s) for metrics.
Understudy Labs Models API
The Models API from Understudy Labs — 2 operation(s) for models.
Understudy Labs Residency API
The Residency API from Understudy Labs — 6 operation(s) for residency.
Understudy Labs Runs API
The Runs API from Understudy Labs — 2 operation(s) for runs.
Understudy Labs Status API
The Status API from Understudy Labs — 1 operation(s) for status.
Understudy Labs Supervision API
The Supervision API from Understudy Labs — 1 operation(s) for supervision.
Scroll for all 12
Open Collections 10
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Understudy Desktop Agent Capabilities API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Conversations API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Downloads API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Feedback API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Metrics API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Models API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Residency API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Runs API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Status API
OPEN COLLECTIONUnderstudy Desktop Agent Capabilities Supervision API
OPEN COLLECTIONScroll for all 10
Arazzo Workflows 1
Multi-step API workflows described with the Arazzo specification.
Download, warm, and chat with a local model on Understudy Desktop
The core Understudy Desktop journey over the loopback Agent API - pick a model from the catalog, start and track its download, add a residency slot, assign and warm the model in...
ARAZZOMCP Servers 1
Model Context Protocol servers that expose these APIs to AI agents.
Agent Skills 3
Packaged agent skills for driving this provider's APIs from an AI assistant.
Spectral Rules 1
Spectral governance rulesets for linting and validating these APIs.
Understudy Labs API Rules
SPECTRALOpenAPI Overlays 1
Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.
Security Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
Recommended x-agentic-access execution contracts for AI agents.
Resources
Get Started 3
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 6
Pagination, idempotency, versioning, errors, and events
Build 3
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Operate 2
Status, limits, changes, and where to get help
Commercial 2
Pricing, plans, and the legal terms of use
Company 2
The organization behind the API
Other 2
Properties that don't map to a standard resource type
Source (apis.yml)
Understudy Labs API — frequently asked questions
Does Understudy Labs have an API?
Yes. APIs.io lists 12 APIs from Understudy Labs, including Understudy Gateway API, Understudy Control Plane API and Understudy Labs Capabilities API, and 9 more.
Is there an OpenAPI specification for the Understudy Labs API?
Yes. APIs.io indexes 10 OpenAPI specifications for Understudy Labs, each linked for download from this page.
How do I authenticate with the Understudy Labs API?
Understudy Labs uses bearer-token authentication (apiKey/http · 5 schemes). The details are profiled on APIs.io as Understudy Labs Authentication.
Does Understudy Labs have an MCP server?
Yes. APIs.io lists 1 MCP server for Understudy Labs: Local (stdio) MCP server; 6 tools listed.
Is the Understudy Labs API ready for AI agents?
Understudy Labs has a Kin Score of 44.4 out of 100 (developing) and an Agent Readiness score of 29.4 (agent-ready), scored by API Evangelist on 2026-11-06.
Work with this as data
Every provider here is available over the APIs.io API and to AI agents over MCP.