@cyanheads/osv-advisory-mcp-server
Query OSV.dev for package vulnerabilities, batch-audit dependency lists, and fetch full advisory records via MCP. STDIO or Streamable HTTP.
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**Public Hosted Server:** [https://osv-advisory.caseyjhand.com/mcp](https://osv-advisory.caseyjhand.com/mcp)
---
## Overview
Vulnerability data from OSV.dev, the open-source vulnerability database. Query a package version or Git commit, batch-audit a dependency list or SBOM, and fetch complete advisory records with CVSS severity, CVE aliases, and affected version ranges.
### Tools
| Tool | Description |
|:---|:---|
| `osv_query_package` | Query a package version by name/ecosystem/version or Package URL (PURL) |
| `osv_query_batch` | Audit up to 1000 package versions in one call — a full dependency list or SBOM |
| `osv_query_commit` | Query known vulnerabilities for a full Git commit hash |
| `osv_get_vulnerability` | Fetch the full advisory record for a single OSV vulnerability ID |
| `osv_list_ecosystems` | Return the list of supported ecosystem identifier strings |
## Capability reference
### `osv_query_package` tool
- Provide `name`, `ecosystem` (case-sensitive exact match), and `version`, or a `purl` such as `pkg:pypi/jinja2@3.1.4`. A PURL needs exactly one version: embedded in the URL or supplied separately. Versions are exact, never ranges
- Unsupported ecosystem-specific constraints fail as `invalid_version`; npm/crates.io exact pins with `=` or `==` normalize to the installed version
- Each advisory carries CVE `aliases`, `severityLabel` with its `severitySource`, the queried package's `fixedVersions`, `affectedRanges`, and `cweIds`
- `truncated: true` means OSV had more pages than `OSV_QUERY_MAX_PAGES` follows, so an empty `vulns` list is not a clean result; an unrecognized ecosystem fails as `invalid_ecosystem`
---
### `osv_query_batch` tool
- 1–1000 `{name, ecosystem, version}` tuples or `{purl, version?}` entries per call; mix either form, and `results[i]` matches `packages[i]`
- Each row carries `vulnerable`, `vulnCount`, `vulns`, `truncated`, and `error`; a failure lands in the affected rows' `error` instead of failing the call
- `summary` totals the scan (`vulnerableCount`, `cleanCount`, `truncatedCount`, `errorCount`, `totalVulns`, `worstSeverity`), and truncated rows never count as clean. The whole scan has a 50-second deadline
- `vulnerableRows`, `errorRows`, and `truncatedRows` in `summary` retain original zero-based indices even when the preview omits those rows. Lists can overlap; retrieve a row with `/results/`
---
### `osv_query_commit` tool
- One full `commit`: 40 hexadecimal characters for SHA-1 or 64 for SHA-256; either letter case is accepted, abbreviations are rejected
- Advisories retain record-wide severity, aliases, and GIT ranges with repository URLs and ordered events. No package-specific `fixedVersions` are inferred
- `truncated: true` means more OSV pages remain; an empty truncated result is not confirmed clean
---
### `osv_get_vulnerability` tool
- One exact advisory ID from any OSV source (`GHSA-`, `PYSEC-`, `RUSTSEC-`, `GO-`, `DSA-`, `USN-`, `CVE-`, …), matched case-sensitively
- Full record: `details`, `aliases`, every affected package with its ranges and fixes, `severityLabel`, `cweIds`, and `references`
- An unknown ID fails as `vulnerability_not_found`; `withdrawn` is set only on retracted advisories
---
### `osv_list_ecosystems` tool
- No input; returns the `ecosystems` strings the query tools accept, plus a `note` with the date the list was last checked against OSV.dev
- Strings are case-sensitive exact matches: `PyPI` works, `pypi` fails
## 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.
OSV-specific:
- No API key required — OSV.dev is public and keyless, with no published rate limit
- `osv_query_batch` finds matching advisory IDs through OSV's `/v1/querybatch`, then fetches each unique advisory once, so batch rows carry the full records (`aliases` included) the batch endpoint omits; requests are capped by `OSV_BATCH_CONCURRENCY`
- `osv_list_ecosystems` is checked against the live OSV schema and API with `bun run check:ecosystems`
Agent-friendly output:
- Truncation is never read as clean — `truncated` flags incomplete OSV pagination, and truncated batch rows are left out of `cleanCount`
- `aliases` (CVE IDs) on every advisory chain to `nist-nvd-mcp-server` for CVSS base scores and CISA KEV status
- Responses are capped at 24,000 bytes. Start retrieval by repeating the original input with `page: overflow.page`. Continue the same `path` with `offset: page.nextOffset` and `revision: page.revision` until `nextOffset` is null. Fetch each `entries[].deferred.path` separately at offset zero without a revision; never copy the whole output `page` object into the input
- Advisory text in `content[]` escapes HTML and unsafe-link constructs while preserving HTTP(S) links; caller coordinates render literally. `structuredContent` keeps every OSV string verbatim
## Getting started
Use the public hosted instance with Claude Code:
```sh
claude mcp add --transport http osv-advisory-mcp-server https://osv-advisory.caseyjhand.com/mcp
```
Or run locally through npm:
```sh
claude mcp add osv-advisory-mcp-server -- npx -y @cyanheads/osv-advisory-mcp-server
```
For other MCP clients, add this to the client configuration:
```json
{
"mcpServers": {
"osv-advisory-mcp-server": {
"command": "npx",
"args": ["-y", "@cyanheads/osv-advisory-mcp-server"]
}
}
}
```
No API key is required. For Docker or a source build, see [Running the server](#running-the-server).
## Configuration
All configuration is validated at startup, and every variable is optional.
| Variable | Description | Default |
|:---------|:------------|:--------|
| `OSV_REQUEST_TIMEOUT_MS` | HTTP request timeout for OSV.dev API calls, in milliseconds. | `10000` |
| `OSV_BATCH_CONCURRENCY` | Maximum concurrent OSV.dev requests issued by `osv_query_batch`. | `10` |
| `OSV_QUERY_MAX_PAGES` | Maximum OSV.dev result pages followed per package or commit before a result is marked `truncated`. | `10` |
| `MCP_TRANSPORT_TYPE` | Transport: `stdio` or `http`. | `stdio` |
| `MCP_HTTP_PORT` | Port for HTTP server. | `3010` |
| `MCP_HTTP_ENDPOINT_PATH` | HTTP endpoint path. | `/mcp` |
| `MCP_PUBLIC_URL` | Public origin override for TLS-terminating reverse-proxy deployments. | none |
| `MCP_SESSION_MODE` | HTTP session mode: `stateless`, `stateful`, or `auto`. | `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` |
| `LOG_TOOL_FAILURE_PAYLOADS` | Log each failed tool call's arguments and result, redacted by key name and capped at `LOG_TOOL_FAILURE_PAYLOAD_MAX_BYTES` (default `16384`). A secret inside a free-form value is not redacted. | `false` |
| `STORAGE_PROVIDER_TYPE` | Storage backend. | `in-memory` |
| `OTEL_ENABLED` | Enable [OpenTelemetry instrumentation](https://github.com/cyanheads/mcp-ts-core/tree/main/docs/telemetry) (spans, metrics, completion logs). | `false` |
See [`.env.example`](./.env.example) for the full list of optional overrides.
## Running the server
### Local development
Requires [Bun v1.4.0](https://bun.sh/) or higher (or Node.js v24+).
```sh
git clone https://github.com/cyanheads/osv-advisory-mcp-server.git
cd osv-advisory-mcp-server
bun install
cp .env.example .env
```
- **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
bun run check:ecosystems # Compare osv_list_ecosystems with the live OSV schema and API
```
### Docker
```sh
docker run --rm -p 3010:3010 ghcr.io/cyanheads/osv-advisory-mcp-server:latest
```
The image defaults to HTTP transport, stateless session mode, and logs to `/var/log/osv-advisory-mcp-server`. For stdio, use `docker run -i --rm -e MCP_TRANSPORT_TYPE=stdio ghcr.io/cyanheads/osv-advisory-mcp-server:latest`. Build locally with `docker build -t osv-advisory-mcp-server .`; OpenTelemetry peers are installed by default — use `--build-arg OTEL_ENABLED=false` to omit them.
## Project structure
| Directory | Purpose |
|:----------|:--------|
| `src/index.ts` | `createApp()` entry point — registers tools and inits services. |
| `src/config` | Server-specific environment variable parsing and validation with Zod. |
| `src/mcp-server/tools` | Tool definitions (`*.tool.ts`) — `osv_query_package`, `osv_query_batch`, `osv_query_commit`, `osv_get_vulnerability`, `osv_list_ecosystems`. |
| `src/services/osv-api` | OSV.dev REST API service — fetch, retry, response normalization. |
| `tests/` | Unit and integration tests mirroring `src/`. |
| `skills/` | Published dependency-audit and advisory-retrieval guide, also served over MCP. |
## Development guide
See [`CLAUDE.md`/`AGENTS.md`](./CLAUDE.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.enrich` for response context, and `ctx.signal` for cancellable OSV requests
- Register new tools via the barrel in `src/mcp-server/tools/definitions/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.