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.

Perseus is profiled on the APIs.io network. Tagged areas include Company, Artificial Intelligence, Developer Tools, Code Search, and Semantic Search.

Perseus’ developer surface includes documentation, getting-started guide, pricing, engineering blog, signup flow, support, CLI, and 7 more developer resources.

🌐 Visit website 📡 Source on GitHub

22.9/100 emerging ▬ flat Agent 6/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

0 APIs

Company Artificial Intelligence Developer Tools Code Search Semantic Search Coding Agents AI AgentsLatent SpaceCLI Agent Skills Y Combinator

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 22.9/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 12.9 / 20

Access Clarity 4.7 / 20

Operational Transparency 0.3 / 13

Contract Governance 0.0 / 12

Discoverability 5.0 / 10

Agent readiness — 6/100 · agent aware

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/perseus: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Perseus Authentication

token · 1 scheme

SECURITY

Perseus Domain Security

TLSv1.3

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

DeveloperPortal

DeveloperPortal

SignUp

SignUp

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgentSkill

AgentSkill

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

CLI

CLI

Packages

Packages

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: perseus
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/perseus.png
name: Perseus
description: '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.'
url: https://raw.githubusercontent.com/api-evangelist/perseus/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
tags:
- Company
- Artificial Intelligence
- Developer Tools
- Code Search
- Semantic Search
- Coding Agents
- AI Agents
- Latent Space
- CLI
- Agent Skills
- Y Combinator
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 6
  pass: local-v1
apis: []
common:
- type: Website
  url: https://perseus.computer
- type: Documentation
  url: https://perseus.computer/docs
- type: GettingStarted
  url: https://perseus.computer/docs
- type: DeveloperPortal
  url: https://perseus.computer/console
- type: Pricing
  url: https://perseus.computer/pricing
- type: Blog
  url: https://perseus.computer/blog
- type: SignUp
  url: https://perseus.computer/console/onboarding?plan=developer_monthly
- type: Support
  url: mailto:hello@perseus.computer
- type: GitHubOrganization
  url: https://github.com/efficientsystemsinc
- type: CLI
  url: cli/perseus-cli.yml
- type: AgentSkill
  url: skills/perseus-code-search.md
- type: Packages
  url: packages/perseus-packages.yml
- type: Authentication
  url: authentication/perseus-authentication.yml
- type: DomainSecurity
  url: security/perseus-domain-security.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io

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