Perseus
Perseus (legal name Efficient Systems Inc.) is an applied AI lab focused on semantic search in latent spaces, founded by Samrath Chadha and backed by Y Combinator (Fall 2025 batch). Its first product is a retrieval engine that grounds coding agents in real code: developers and agents describe the code they are looking for in plain English and Perseus returns ranked file:line results with snippets in seconds, indexing the working tree (including uncommitted edits) so models like Claude Code, Cursor, and Codex can find the right context before editing. Rather than a public REST API, Perseus ships a first-party CLI (installed via a curl/PowerShell one-liner, as a PyInstaller binary or uv wheel), a provider-published Agent Skill, and a Factory Droid plugin, all under the efficientsystemsinc GitHub organization. The developer surface — docs, console, pricing, and blog — is live; there is no OpenAPI, MCP server, or /.well-known discovery document published as of this pass.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles Perseus the way a machine reads it — 2 machine-readable artifacts, 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 — Perseus scores 23.9/100 (emerging), with a separate agent-readiness read of 14/100 (human only). 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.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Perseus
Each block below is one kind of artifact we hold for Perseus. 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.
Security 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.
Resources
Every other property we hold for Perseus — 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 1
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Build 3
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 2
The organization behind the API
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