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.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Understudy Labs the way a machine reads it — 28 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Understudy Labs scores 43.2/100 (developing), with a separate agent-readiness read of 29/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
Put this on your own site. The badge is drawn live from Understudy Labs's current Kin Score — paste it once and it updates itself every time the score is recomputed. It follows your visitor's light or dark setting, and it links back here so anyone who sees it can read the full breakdown.
<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/understudy-labs/"
title="Understudy Labs on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/understudy-labs.svg"
alt="Understudy Labs Kin Score — API readiness rating by API Evangelist" width="150" height="150" loading="lazy">
</a>[](https://providers.apievangelist.com/providers/understudy-labs/)<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/understudy-labs/"
title="Understudy Labs on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/understudy-labs/card.svg"
alt="Understudy Labs Kin Score — API readiness rating by API Evangelist" width="340" height="120" loading="lazy">
</a>More shapes, themes and sizes → · Score as JSON · How badges work
How we profile Understudy Labs
Each block below is one kind of artifact we hold for Understudy Labs. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 12
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
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 within the panel for all 12 ·
Open Collections 11
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
API Collection
OPEN COLLECTIONUnderstudy 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 within the panel for all 11 ·
Arazzo Workflows 1
Real integrations are rarely a single call. Arazzo describes the multi-step sequences — auth, then create, then confirm — so both a human and an agent can follow the choreography, not just the endpoints.
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 expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
Understudy Labs MCP Server
MCP SERVERSecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Understudy Labs — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
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 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/understudy-labs · machine-readable index on apis.io
This is an independent, third-party profile of Understudy Labs, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
info@apievangelist.com
·
Read the full data-sourcing policy →
On a security or compliance team? Put security in the subject line and
you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.