Download plugins/social-readers/skills/yc-reader/SKILL.md from the publisher, or copy the path and open the repository. PlugMCP lists the skill and does not host the file.
Where does yc-reader live?
The publisher keeps it at https://github.com/himself65/finance-skills.
Which agents can use yc-reader?
Claude, Cursor, and Codex can read a SKILL.md you add from the publisher's repository.
>
name: yc-reader
description: >
Look up Y Combinator companies and batches from the public yc-oss API, a static JSON
dataset refreshed daily: company profiles, batch rosters (e.g. W25, S24), companies
by industry or tag, top companies, who is hiring, founder-diversity lists, and
overall YC stats. Use this skill whenever the user asks about YC-backed startups, a
YC batch, YC companies in a sector or tag or that are hiring, the Y Combinator
portfolio, or startup and venture research that draws on YC data. Read-only.
Y Combinator Reader (Read-Only)
Fetches Y Combinator company data from the yc-oss/api, an unofficial open-source API that indexes all publicly launched YC companies. The data is sourced from YC's Algolia search index and updated daily via GitHub Actions.
This is a read-only data source. It provides company profiles, batch listings, industry/tag breakdowns, hiring status, and diversity data. No write operations exist — the API serves static JSON files.
No authentication required. The API is public and free. Just use curl to fetch JSON endpoints.
Step 1: Verify Prerequisites
This skill only needs curl (to fetch data) and jq (to parse/filter JSON). Both are pre-installed on most systems.
Batches use {season}-{year} format: winter-2026, spring-2026, summer-2026, fall-2025. Older batches follow the same pattern back to summer-2005. The short form (w09, s21) also works for the per-company endpoint.
Industry and tag name format
Use lowercase with hyphens for multi-word names: real-estate, developer-tools, machine-learning.
Step 3: Execute the Request
Base URL
https://yc-oss.github.io/api/
General pattern
# Fetch and pretty-print
curl -s https://yc-oss.github.io/api/companies/top.json | jq .
# Count companies in a result
curl -s https://yc-oss.github.io/api/batches/winter-2025.json | jq length
# Filter by field (e.g., hiring companies in a batch)
curl -s https://yc-oss.github.io/api/batches/winter-2025.json | jq '[.[] | select(.isHiring == true)]'
# Extract specific fields
curl -s https://yc-oss.github.io/api/companies/top.json | jq '.[] | {name, one_liner, batch, team_size, website}'
# Search by name (case-insensitive)
curl -s https://yc-oss.github.io/api/companies/all.json | jq '[.[] | select(.name | test("stripe"; "i"))]'
Key rules
Use -s flag with curl to suppress progress output
Pipe through jq for readable output and filtering
Avoid fetching companies/all.json unless necessary — it's a large response (~5,700 companies). Prefer more specific endpoints (batches, industries, tags) when possible
Use jq select/filter to narrow results client-side when the API doesn't have a specific endpoint for what the user wants
Batch names are lowercase with hyphens — winter-2025 not Winter 2025 or W25
Tag and industry names are lowercase with hyphens — developer-tools not Developer Tools
Common jq filters
Filter
Purpose
jq length
Count results
jq '.[0]'
First company
jq '.[:10]'
First 10 companies
jq '[.[] | select(.isHiring == true)]'
Only hiring companies
jq '[.[] | select(.status == "Active")]'
Only active companies
jq '[.[] | select(.team_size > 100)]'
Companies with 100+ employees
jq '.[] | {name, one_liner, batch, website}'
Select specific fields
jq '[.[] | select(.name | test("query"; "i"))]'
Search by name
jq 'sort_by(-.team_size) | .[:10]'
Top 10 by team size
Step 4: Present the Results
Summarize rather than dump JSON. For each company, give the name, one-liner, batch, team size, status, hiring status (a growth signal), and website. For a batch, lead with its size and notable companies; for an industry or tag, the count and which companies are top or hiring; for research questions, aggregate stats such as counts, common industries, and team-size distribution. Mention that the dataset refreshes daily.
Step 5: Diagnostics
If a request fails:
Error
Cause
Fix
404 Not Found
Invalid batch, industry, or tag name
Check meta.json for valid names
Empty array []
No companies match the query
Broaden the search or check spelling
curl: Could not resolve host
No internet connection
Check network connectivity
Large/slow response
Fetching companies/all.json (5,700+ entries)
Use a more specific endpoint or add jq filters
To discover valid batch, industry, and tag names:
# List all batches
curl -s https://yc-oss.github.io/api/meta.json | jq '.batches[].name'
# List all industries
curl -s https://yc-oss.github.io/api/meta.json | jq '.industries[].name'
# List all tags (there are 333+)
curl -s https://yc-oss.github.io/api/meta.json | jq '.tags[].name'
Reference Files
references/api_reference.md — Complete endpoint reference with company schema, all endpoint URLs, and research workflow examples
Read the reference file when you need the exact company field schema, valid batch/industry/tag names, or detailed research workflow patterns.
How do I install yc-reader?
Download plugins/social-readers/skills/yc-reader/SKILL.md from the publisher, or copy the path and open the repository. PlugMCP lists the skill and does not host the file.
Where does yc-reader live?
The publisher keeps it at https://github.com/himself65/finance-skills.
Which agents can use yc-reader?
Claude, Cursor, and Codex can read a SKILL.md you add from the publisher's repository.