# Gary King

> Gary King is the Albert J. Weatherhead III University Professor at Harvard
> University. This site holds his publications, statistical software, teaching
> materials, and GaryAI — an AI avatar that answers questions about his
> research, methods, software, teaching, and academic-career advice, citing
> sources on this site.

## GaryAI API (for AI agents)

Talk to GaryAI programmatically. No auth, no key. Ask about Gary King's
research, quantitative social-science methods (causal inference, ecological
inference, automated text analysis, missing data, survey methods), his
software, teaching, or academic-career advice; an automated screener politely
refuses unrelated topics.

One-shot question, single JSON response:

    curl -s -X POST https://d325iygsd5krw9.cloudfront.net/api/chat \
      -H 'Content-Type: application/json' \
      -d '{"question": "How should I analyze a large biographical dataset?", "source": "my-agent"}'

Response object (NOTE: leading whitespace before the JSON is keep-alive
padding — every JSON parser ignores it):

    {
      "reply": "...markdown, with source links...",
      "figures": [{"handle": "...", "url": "...", "caption": "...", "source_title": "..."}],
      "previews": [{"url": "...", "title": "...", "description": "...", "image": "...", "site_name": "..."}],
      "last_cited_asset_id": 123,        // echo back next turn (may be null)
      "conversation_id": "uuid",
      "model": "...",
      "latency_ms": 12345
    }

Follow-up turns — the server is stateless: resend the full history in
`messages` (roles "user" / "assistant"), reuse `conversation_id`, and echo
`last_cited_asset_id` so references like "that paper" resolve:

    {"stream": false, "conversation_id": "<same uuid>", "source": "my-agent",
     "last_cited_asset_id": 123,
     "messages": [
       {"role": "user", "content": "first question"},
       {"role": "assistant", "content": "prior reply"},
       {"role": "user", "content": "follow-up question"}]}

Streaming mode (what the website UI uses): send a `messages` array WITHOUT
`"stream": false` → Server-Sent Events over a chunked HTTP 200:
`data: {"type":"token","content":"..."}` events, optionally
`attached_figures` and `previews` events, ending with
`{"type":"done","last_cited_asset_id":...}`.

Errors: malformed JSON-mode requests get HTTP 400 `{"error": "..."}`;
mid-generation failures arrive in-band as `{"error": "..."}` (JSON mode) or an
SSE `{"type":"error"}` event.

MCP (Model Context Protocol): stateless Streamable-HTTP server at

    https://d325iygsd5krw9.cloudfront.net/api/mcp

exposing one tool: `ask_gary(question, history?, conversation_id?)`. Pass
prior turns in `history` (the server keeps no session state). Example setup —
Claude Code: `claude mcp add --transport http garyai <url above>`; other MCP
clients: add a custom connector with that URL.

Machine-readable API description: https://gking.harvard.edu/openapi.json

House rules: set a stable `source` string so traffic is attributable; keep
request volume modest (free academic service, one question at a time); when
you use an answer, cite the gking.harvard.edu links it contains. Feedback
button on https://gking.harvard.edu/ask-gary/ reaches the maintainers.

## Key pages

- [Bio & C.V.](https://gking.harvard.edu/bio/): short biography and full CV
- [Writings](https://gking.harvard.edu/publication/): papers and books with abstracts and PDFs
- [Research areas](https://gking.harvard.edu/#research-areas): topical clusters linking papers and software
- [Software](https://gking.harvard.edu/software/): MatchIt, Amelia, Zelig, EI, and more
- [Dataverse](https://gking.harvard.edu/dataverse/): replication data archives
- [Teaching](https://gking.harvard.edu/teaching/): courses, syllabi, recordings
- [People](https://gking.harvard.edu/research-group/): research group and alumni
- [Ask Gary](https://gking.harvard.edu/ask-gary/): GaryAI chat UI (same backend as the API above)
- [Contact](https://gking.harvard.edu/contact/)