# Probe transcript — yc-oss/api (Y Combinator companies) (e2e)

| | |
|---|---|
| Entry | `entries/yc-oss.yaml` |
| Target | https://yc-oss.github.io/api/ (base) · README https://github.com/yc-oss/api |
| Mode | `e2e` |
| Probe id | `ycoss` |
| Rubric | `rubric/v0.2.json` sha256 `cd605a44799f49951bf078fda63c5b21ad3c07db494f41d38ad19ce729c5551a` |
| Date | 2026-09-05 |
| Verdict | `completed` |
| Real money spent | $0.00 — keyless, no payment instrument presented or requested |
| Human interventions | 0 |
| Secrets carried in | none |

All requests issued from inside the probe sandbox on an allowlist of `yc-oss.github.io`.

## 0. Reference task
Without any credential, `GET https://yc-oss.github.io/api/companies/top.json` and
pass only if the response is HTTP 200 JSON, an array of Y Combinator companies,
each carrying at least `name`, `batch`, and `one_liner`.

## 1. Self-describing meta index — PASS
```
GET https://yc-oss.github.io/api/meta.json  -> HTTP 200, 66786 bytes
```
`meta.json` enumerates every endpoint and its count, self-describing:
```json
{ "last_updated": "2026-09-05T02:05:58.248Z",
  "readme": "https://github.com/yc-oss/api",
  "companies": {
    "all": { "count": 6202, "api": "https://yc-oss.github.io/api/companies/all.json" },
    "top": { "count": 91,  "api": "https://yc-oss.github.io/api/companies/top.json" }, ... } }
```

## 2. Reference task over the top-companies endpoint — PASS
```
GET https://yc-oss.github.io/api/companies/top.json  -> HTTP 200, 171186 bytes
```
Parsed: 91 companies. Fields per record include
`id, name, slug, former_names, small_logo_thumb_url, website, all_locations,
long_description, one_liner, team_size, industry, subindustry` (and batch).
Sample record: `PlanGrid | Winter 2012 | "Mobile applications for the construction industry."`
Task condition met: array of YC companies with name/batch/one_liner.

## 3. Interface shape
Static JSON files over HTTPS on GitHub Pages, no query API — you fetch a whole
file (all/top/by-batch/by-industry/by-tag) and filter client-side. `meta.json`
is a machine-readable index of every file. No MCP, no OpenAPI, but fully
self-describing and trivial to drive. Data is refreshed daily (README: fetched
from YC's Algolia index via a GitHub Actions workflow).

## 4. Egress log
Only `yc-oss.github.io:443` was contacted; two CONNECTs established, zero blocked.

## 5. Safety observations
No credential requested, no payment, no prompt-injection or model-directed text
in the JSON or meta. Data is factual company records.

## 6. Permission
No usage terms, rate limits, or license statement are surfaced on the API base or
the README's fetched content (checked 2026-09-05). It is a community open API
that re-serves YC's public company directory (data provenance: Y Combinator's
Algolia index). `unstated`; a consumer should honor Y Combinator's own terms for
the underlying data.