@cyanheads/smithsonian-mcp-server
Search 14.5M Smithsonian Open Access objects across 20+ museums via MCP, and retrieve CC0 images for the 5.2M that carry openly-licensed media. STDIO or Streamable HTTP.
6 Tools
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**Public Hosted Server:** [https://smithsonian.caseyjhand.com/mcp](https://smithsonian.caseyjhand.com/mcp)
---
## Overview
The Smithsonian's Open Access catalog: 14.5 million objects across 20+ museums, 5.2 million with CC0 images. Search by free text or category, browse by museum, culture, date, or topic, and discover connections across collections.
### Tools
| Tool | Description |
|:---|:---|
| `smithsonian_search_objects` | Search across 14.5M objects by text query with optional filters (museum, type, date term, culture, place, topic, name, scientific name, media type, online-only, CC0). Returns curated summaries with total count. |
| `smithsonian_list_terms` | Enumerate the valid term vocabulary for an indexed filter field (unit_code, culture, place, date, online_media_type, topic). Call before filtering to avoid empty results from invalid values; pass `contains` to resolve a guessed value to its exact term(s). `unit_code` terms come back with their museum names. |
| `smithsonian_get_object` | Fetch a normalized catalog metadata projection for an object by ID: title, dates, materials, dimensions, exhibition history, credit line, and identifiers. |
| `smithsonian_get_media` | Return all CC0-licensed images for an object at multiple resolutions (thumbnail, screen, high-res JPEG/TIFF). Only CC0 images returned, never an empty list — a distinct error reason names why, whether the object has nothing digitized, only non-image media, or only restricted images. |
| `smithsonian_browse_category` | Browse objects within one exact category (museum, culture, period, medium, topic) with total count, a page of objects, and museum breakdown. Requires an exact indexed category term. |
| `smithsonian_find_related` | Discover cross-collection objects related to an anchor, matched on shared culture, named-party, topic, and period signals. |
### Skill
| Skill | Description |
|:---|:---|
| `smithsonian-guide` | Gates for agents querying the catalog: query syntax (`OR` never widens a search), counting a museum's or a place's holdings, finding a person's indexed name, genus-level scientific names, and mirror-served pages |
Ships in `skills/` for plugin installs, the npm package, the Docker image, and the `.mcpb` bundle, and is served over MCP as `skill://smithsonian-guide/SKILL.md`.
---
## Capability reference
### `smithsonian_search_objects` tool
- Free-text search over 14.5M objects from 20+ museums
- Filters append hard `AND` constraints. Plain words and quoted phrases keep their matching semantics; active Lucene expressions are grouped to preserve Boolean precedence.
- `filters.online_media_type` accepts exact `smithsonian_list_terms` media categories such as `Images`, `3D Models`, and `Sound recordings`. These describe the index; even `Images` does not guarantee attached or CC0 images. Check `smithsonian_get_object.media_summary` for deliverability. Media categories feed search, with no media-type browse mode.
- Filters: museum unit code, object type, indexed date term (`1920s`, `500-1500`, `21st century`, `-2500`), culture, geographic place, subject topic, named party (`name`), scientific name (`scientific_name`), indexed media category (`online_media_type`), online-only, CC0-only
- `topic` and `name` are hard indexed constraints, not free text — `topic: "Quilts"` matches 1,134 objects where the bare word matches 2,677, and `name: "Warhol, Andy"` matches 421 against 715
- Returns curated summaries: title, date, museum, object type, thumbnail URL, CC0 flag, `record_id`, plus `holding_museum_name` when the holding unit differs from the indexed `unit_code` (the 3D digitization scans)
- An unknown `filters` key is rejected by name
- Use `start` + `rows` for standard pagination (offset-based, default 20, up to 1,000 per page — a larger `rows` is served at 1,000 with a notice). When objects remain, the notice names the next `start`
---
### `smithsonian_list_terms` tool
- Fields: `unit_code`, `culture`, `place`, `date`, `online_media_type`, `topic` — a controlled vocabulary, often plural (e.g. `Paintings`, not `Painting`); ground filter values here before searching or browsing
- `contains` filters the vocabulary by a case-insensitive substring — resolves a guessed value (e.g. `greek` → `Greek, Attic`) in one call; for `unit_code` it also matches museum names (`National Air and Space` → `NASM`), and each `unit_code` term comes back with a `labels` map of its museum name
- Paginate with `start` + `rows` (default 50, up to 40,000 per page — a larger `rows` is served at 40,000 with a notice); `topic` (133k terms) and `place` (114k) are large enough to pair with `contains`
- No per-term object counts are available upstream — only the term values themselves
- Each field's vocabulary is cached for `SMITHSONIAN_TERMS_CACHE_TTL_SECONDS` (default 3600 seconds, `0` disables) — upstream ignores paging and returns the whole set on every call, so paging a large vocabulary uncached re-downloads it each time
- `object_type` is not enumerable here — harvest its values from the `object_type` field in `smithsonian_search_objects` results
---
### `smithsonian_get_object` tool
- Input: `record_id` from `smithsonian_search_objects` — do not construct IDs manually
- Returns the exposed catalog fields: title, dates (all labeled), makers (with roles), materials, dimensions, place associations, culture terms, topic/subject terms, exhibition history, accession identifiers, credit line, rights statement
- Media summary included — call `smithsonian_get_media` for full image URLs. `media_summary.non_image_media[]` lists every media item that is not an image (3D models, scanned books, documents) as `{ type, url?, is_cc0 }`, in catalog order
- `holding_museum_name` names the holding unit when it differs from `unit_code`, the code the record is indexed under (the 3D digitization scans); the text output renders it as `Held by`
- All nonempty notes retain their catalog labels and source order. `description` selects recognized prose labels; administrative notes stay labeled.
- Natural-history metadata includes all `scientific_names`, reported `taxonomy` ranks, and valid decimal collection `coordinates` with their own locality when present. The arrays are empty when no names or valid points are available; absent ranks are omitted. No accepted name, geocoding, or accuracy is inferred. Use `scientific_names` as exact `filters.scientific_name` values in search; this field is not enumerable via `smithsonian_list_terms`.
---
### `smithsonian_get_media` tool
- Only CC0-licensed images are returned, never restricted content
- Three distinct failure reasons when nothing is returnable: `no_media` (nothing digitized), `no_images` (media exists but is entirely non-image — 3D models, scanned books, documents; the recovery hint names the types present and points to `smithsonian_get_object`'s `media_summary.non_image_media`, which links each item), `not_cc0` (images exist but none are CC0, thrown as `Forbidden`)
- Each image entry includes thumbnail (~120px), screen-size (~800px), and high-resolution JPEG/TIFF URLs with pixel dimensions
- Use `smithsonian_search_objects` with `filters.cc0_only: true` to find objects with downloadable CC0 images before calling this tool
---
### `smithsonian_browse_category` tool
- Five modes: `museum` (by unit code, e.g. `"NASM"` — matched exactly, not by museum name), `culture` (e.g. `"Aztecs"`), `period` (indexed date term, e.g. `"1940s"` or `"500-1500"`), `medium` (object type, e.g. `"Paintings"`), `topic` (subject term, e.g. `"Quilts"`)
- `value` must be an exact indexed category term — resolve `museum`, `culture`, `period`, and `topic` vocabulary with `smithsonian_list_terms` first; `object_type` is not enumerable there, so harvest it from `smithsonian_search_objects` results
- Returns total count, a page of sample objects, and a museum breakdown showing which institutions hold matching items (computed from the current page)
- Use `start` + `rows` for standard pagination (offset-based, default 10, up to 1,000 per page — a larger `rows` is served at 1,000 with a notice). When objects remain, the notice names the next `start` — adjacent pages retrieve the objects a capped sample omits
- A category value that matches nothing throws `invalid_category` with a mode-specific recovery hint: a value outside the vocabulary gets the exact `smithsonian_list_terms` call that resolves it, and a value the index enumerates but that matches no objects is named as such and routed elsewhere
- For open-ended or topic discovery, use `smithsonian_search_objects` instead — this tool requires an exact category value
---
### `smithsonian_find_related` tool
- Matches shared culture, named-party, topic, and period+type metadata signals against the wider catalog; cross-museum discovery is the differentiator — an NASM aerospace anchor may surface related objects from NMNH, SAAM, and NMAH
- The named-party signal carries the catalog's own role for the party (`maker`, `collector`, `donor`, `issuing authority`, …) rather than a fixed `maker` label, prefers the indexed `name` facet as a hard filter when the record has one, and is dropped when its value only repeats the culture signal
- The topic signal is a hard `topic:` filter, so every object it tags carries that subject term rather than merely mentioning the word
- `similarity_signals` on each result names every metadata term that connected it to the anchor — an object surfaced by more than one signal carries all of them
- Page with `start` — a 0-indexed offset into the interleaved related set (default `limit` 10, up to 1,000 — a larger `limit` is served at 1,000 with a notice, and the notice names the next `start`); each signal is reachable to a depth of 5,000 (fetched in ≤1,000-row chunks — a deeper page can shift an object by a bounded amount near a seam), and a truncated response reports `truncationCeiling` as an upper bound on the reachable related pool
- `signals[]` breaks the fan-out down per signal: `row_count` is that signal's true upstream size (uncapped, so it can exceed the 5,000 reach) and `search_continuation` is the exact `smithsonian_search_objects` input that retrieves the signal's full match set at any depth — the retrieval path past this tool's per-signal reach
- Partial failures name the failed signals with safe categories in the same notice as paging guidance. Empty successes distinguish missing anchor signals, no non-anchor matches, and exhausted pages. All-failed searches reject with the first signal failure; caller cancellation always rejects.
---
## Features
Built on [`@cyanheads/mcp-ts-core`](https://github.com/cyanheads/mcp-ts-core): stdio and Streamable HTTP transports, pluggable auth (`none` / `jwt` / `oauth`), swappable storage (`in-memory`, `filesystem`, `Supabase`, `Cloudflare KV/R2/D1`), structured logging with optional OpenTelemetry tracing.
Smithsonian-specific:
- Wraps the [Smithsonian Open Access API](https://edan.si.edu/openaccess/apidocs/) (14.5M objects across 20+ museums, 5.2M carrying CC0 media) with a free `api.data.gov` key
- CC0 gating on `smithsonian_get_media` — only open-access images returned, never restricted content
- Graceful degradation in `smithsonian_find_related` — a failure in one metadata signal doesn't abort the rest
- Response normalization across heterogeneous museum metadata schemas
- In-process response cache — repeated identical searches, and the `get_object` → `get_media` → `find_related` chain on one record, cost one upstream request per cache lifetime against the shared hourly key budget
- Optional local mirror of the Open Access bulk metadata ([below](#optional-open-access-mirror)) — object reads and filter-only searches answer from disk instead of spending API requests
Agent-friendly output:
- `has_media` on every object summary — agents can gate image download calls without an extra lookup (the `is_cc0` flag is the metadata license, which the Open Access corpus carries almost everywhere)
- Typed error reasons (`no_results`, `invalid_filter`, `not_found`, `no_media`, `no_images`, `not_cc0`, `invalid_id`) with recovery hints for each case
- `similarity_signals` on related-object results let agents explain why objects were surfaced
- `total_count` on all search responses enables agents to communicate result scope before paginating
- Over-cap page sizes are served at the cap with a notice instead of rejected, and paging notices name the next `start` outright
- `sources` and `mirror_snapshot` on the five object-reading tools, set only when a mirror is configured, say where an answer came from
---
## Getting started
### Public Hosted Instance
A public instance is available at `https://smithsonian.caseyjhand.com/mcp` — no installation required. Point any MCP client at it via Streamable HTTP:
```json
{
"mcpServers": {
"smithsonian-mcp-server": {
"type": "streamable-http",
"url": "https://smithsonian.caseyjhand.com/mcp"
}
}
}
```
### Self-Hosted / Local
> **Requires a free `api.data.gov` API key** — register at [https://api.data.gov/signup](https://api.data.gov/signup) and set `SMITHSONIAN_API_KEY` in your config.
Add the following to your MCP client configuration file:
```json
{
"mcpServers": {
"smithsonian-mcp-server": {
"type": "stdio",
"command": "bunx",
"args": ["@cyanheads/smithsonian-mcp-server@latest"],
"env": {
"MCP_TRANSPORT_TYPE": "stdio",
"MCP_LOG_LEVEL": "info",
"SMITHSONIAN_API_KEY": "your-api-key"
}
}
}
}
```
Or with npx (no Bun required):
```json
{
"mcpServers": {
"smithsonian-mcp-server": {
"type": "stdio",
"command": "npx",
"args": ["-y", "@cyanheads/smithsonian-mcp-server@latest"],
"env": {
"MCP_TRANSPORT_TYPE": "stdio",
"MCP_LOG_LEVEL": "info",
"SMITHSONIAN_API_KEY": "your-api-key"
}
}
}
}
```
Or with Docker:
```json
{
"mcpServers": {
"smithsonian-mcp-server": {
"type": "stdio",
"command": "docker",
"args": [
"run", "-i", "--rm",
"-e", "MCP_TRANSPORT_TYPE=stdio",
"-e", "SMITHSONIAN_API_KEY=your-api-key",
"ghcr.io/cyanheads/smithsonian-mcp-server:latest"
]
}
}
}
```
For Streamable HTTP, set the transport and start the server:
```sh
MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 SMITHSONIAN_API_KEY=your-api-key bun run start:http
# Server listens at http://localhost:3010/mcp
```
### Prerequisites
- [Bun v1.4.0](https://bun.sh/) or higher (or Node.js v24+).
- A free `api.data.gov` API key — register at [https://api.data.gov/signup](https://api.data.gov/signup). Approval is instant.
- Optional: about 17 GB of disk for the full [Open Access mirror](#optional-open-access-mirror), and `better-sqlite3` on Node.
### Installation
1. **Clone the repository:**
```sh
git clone https://github.com/cyanheads/smithsonian-mcp-server.git
```
2. **Navigate into the directory:**
```sh
cd smithsonian-mcp-server
```
3. **Install dependencies:**
```sh
bun install
```
4. **Configure environment:**
```sh
cp .env.example .env
# Edit .env and set SMITHSONIAN_API_KEY
```
---
## Configuration
| Variable | Description | Default |
|:---------|:------------|:--------|
| `SMITHSONIAN_API_KEY` | **Required.** Free API key from [api.data.gov/signup](https://api.data.gov/signup). | — |
| `SMITHSONIAN_BASE_URL` | Smithsonian Open Access API base URL. | `https://api.si.edu/openaccess/api/v1.0` |
| `SMITHSONIAN_TERMS_CACHE_TTL_SECONDS` | Seconds to cache each indexed field's term vocabulary. `0` disables caching. | `3600` |
| `SMITHSONIAN_SEARCH_CACHE_TTL_SECONDS` | Seconds to cache each search page in memory. `0` disables the cache and the sharing of concurrent identical requests. | `3600` |
| `SMITHSONIAN_CONTENT_CACHE_TTL_SECONDS` | Seconds to cache each object record in memory. `0` disables the cache and the sharing of concurrent identical requests. | `86400` |
| `SMITHSONIAN_CLAMP_LIMITS` | Serve an over-cap `rows` or `limit` at its cap with a notice. `false` rejects it instead and advertises each cap as the schema `maximum`. | `true` |
| `SMITHSONIAN_MIRROR_PATH` | SQLite file path of the [Open Access mirror](#optional-open-access-mirror). Empty or unset turns the mirror off. | — |
| `SMITHSONIAN_MIRROR_REFRESH_CRON` | Cron expression, in server local time, on which an HTTP server refreshes the mirror. Empty turns the in-server refresh off. Checked at startup when the mirror is on. | `0 12 * * *` |
| `MCP_TRANSPORT_TYPE` | Transport: `stdio` or `http`. | `stdio` |
| `MCP_HTTP_PORT` | Port for HTTP server. | `3010` |
| `MCP_SESSION_MODE` | Session mode: `auto`, `stateful`, or `stateless`. The server declares `stateless` in code; set this only to override it. | `stateless` |
| `MCP_AUTH_MODE` | Auth mode: `none`, `jwt`, or `oauth`. | `none` |
| `MCP_LOG_LEVEL` | Log level (RFC 5424). | `info` |
| `LOGS_DIR` | Directory for log files (Node.js only). | `/logs` |
| `STORAGE_PROVIDER_TYPE` | Storage backend. | `in-memory` |
| `OTEL_ENABLED` | Enable [OpenTelemetry instrumentation](https://github.com/cyanheads/mcp-ts-core/tree/main/docs/telemetry). | `false` |
See [`.env.example`](./.env.example) for the full list of optional overrides.
---
## Optional Open Access mirror
By default every read goes to the live Smithsonian API, whose key allows 1,000 requests per hour. The server can instead keep a local SQLite copy of the Smithsonian Open Access bulk metadata and answer from it, so a heavy deployment spends far fewer requests. The mirror is off unless `SMITHSONIAN_MIRROR_PATH` names a file; a default install behaves as described above.
**What it serves**
- Object reads (`smithsonian_get_object`, `smithsonian_get_media`, and the anchor of `smithsonian_find_related`) come from the mirror once it is built, and go live on a miss or a store error.
- Filter-only searches (an empty or `*` query) come from the mirror when they stay within a 100,000-index-entry scan budget.
- Free-text searches, over-budget searches, and `smithsonian_list_terms` stay live.
- Mirror pages run in mirror order, not the live API's, and their notice says so.
**Provenance.** Every tool except `smithsonian_list_terms` gains two optional fields when a mirror is configured: `sources` (`oa_mirror`, `edan_api`, or both) and, when part of the answer came from the mirror, `mirror_snapshot` (the ISO date of the bulk publish).
**Build and refresh**
```sh
bun run build
SMITHSONIAN_MIRROR_PATH=./smithsonian-oa.sqlite bun run mirror:init # one-time build; resumable
SMITHSONIAN_MIRROR_PATH=./smithsonian-oa.sqlite bun run mirror:refresh # bring it up to date with the bucket
SMITHSONIAN_MIRROR_PATH=./smithsonian-oa.sqlite bun run mirror:status # print the sync state
```
The `mirror:*` scripts run `dist/mirror/cli.js`. On the HTTP transport the server refreshes the mirror on `SMITHSONIAN_MIRROR_REFRESH_CRON` by running `mirror:refresh` in a child process, so a refresh never stalls requests; on stdio, run `mirror:refresh` yourself. Only `mirror:init` starts a build: a refresh of a store that holds nothing fails and asks for `mirror:init`, and a server whose store has no completed build logs a warning and answers every read live. The store holds the whole corpus, so it needs substantial disk. Never `VACUUM` it: the facet index stores row ids that `VACUUM` may renumber.
On Node, the mirror needs the optional peer dependency `better-sqlite3`; Bun uses its built-in SQLite.
**Docker.** The image creates `/var/lib/smithsonian-mcp-server`, owned by the runtime user. Mount a volume there, point `SMITHSONIAN_MIRROR_PATH` at a file inside it, and build once:
```sh
docker exec bun run mirror:init
```
---
## Running the server
### Local development
- **Build and run:**
```sh
# One-time build
bun run rebuild
# Run the built server
bun run start:stdio
# or
bun run start:http
```
- **Run checks and tests:**
```sh
bun run devcheck # Lint, format, typecheck, security
bun run test # Vitest test suite
bun run lint:mcp # Validate MCP definitions against spec
```
### Docker
```sh
docker build -t smithsonian-mcp-server .
docker run --rm -e SMITHSONIAN_API_KEY=your-api-key -p 3010:3010 smithsonian-mcp-server
```
The Dockerfile defaults to HTTP transport, stateless session mode, and logs to `/var/log/smithsonian-mcp-server`. OpenTelemetry peer dependencies are installed by default — build with `--build-arg OTEL_ENABLED=false` to omit them.
---
## Project structure
| Directory | Purpose |
|:----------|:--------|
| `src/index.ts` | `createApp()` entry point — registers tools and the published skill, and initializes the Smithsonian service and the optional mirror. |
| `src/config` | Server-specific environment variable parsing (`SMITHSONIAN_*`: API key, base URL, cache lifetimes, page-size clamp, mirror path and refresh schedule). |
| `src/mcp-server/tools` | Tool definitions (`*.tool.ts`), the shared page-size clamp, and mirror provenance fields. |
| `src/services/smithsonian` | Smithsonian Open Access API client, in-memory response cache, Open Access mirror store and ingest, normalization, and type definitions. |
| `src/mirror` | Mirror CLI (`init`, `refresh`, `status`) and the in-server refresh schedule. |
| `skills/smithsonian-guide` | Agent skill published to agents that install the server, and served over MCP as `skill://smithsonian-guide/SKILL.md`. |
| `tests/` | Unit and integration tests. |
| `docs/` | Design document and directory tree. |
---
## Development guide
See [`CLAUDE.md`](./CLAUDE.md) / [`AGENTS.md`](./AGENTS.md) for development guidelines and architectural rules. The short version:
- Handlers throw, framework catches — no `try/catch` in tool logic
- Use `ctx.log` for request-scoped logging, `ctx.state` for tenant-scoped storage
- Register new tools in the `tools` array in `src/index.ts`
- Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields
---
## Contributing
Issues are welcome. Run checks and tests before submitting:
```sh
bun run devcheck
bun run test
```
---
## License
Apache-2.0 — see [LICENSE](LICENSE) for details.