depsdevmcp

An MCP server for deps.dev, built in Go with the github.com/edoardottt/depsdev stable v3 client module.

The server communicates over stdio or streamable HTTP, supports MCP protocol version 2026-07-28, and returns both structured JSON and a JSON text fallback for every tool result.

Tools

| Tool | Purpose | | --- | --- | | depsdev_get_package | Package metadata and known versions | | depsdev_get_version | Exact version metadata, licenses, and advisories | | depsdev_get_dependencies | Resolved dependency graph | | depsdev_find_dependency_path | Target versions and compact chains through a resolved dependency graph | | depsdev_get_requirements | Declared dependency requirements | | depsdev_get_project | GitHub, GitLab, or Bitbucket project metadata | | depsdev_get_project_package_versions | Project-to-package-version mappings | | depsdev_get_advisory | OSV advisory details | | depsdev_query | Version-key or content-hash query | | depsdev_generate_dependency_graph | Graphviz DOT dependency graph |

All tools are read-only and are annotated as such in their MCP definitions.

Security contract

The MCP tool surface has the following application-level guarantees:

• Read-only: every upstream API operation is an HTTPS GET. The graph and dependency-path tools only transform retrieved data in memory. The tools do not mutate deps.dev or persistent local state, and their MCP definitions set readOnlyHint: true and destructiveHint: false.
• Fixed upstream: outbound API requests are constructed against the fixed https://api.deps.dev/v3 base URL. Tool inputs select deps.dev resources or query parameters; no tool accepts a destination URL, so an MCP caller cannot use the server to fetch an arbitrary URL.
• No filesystem tools: no tool lists, reads, creates, changes, or deletes local files. Configuration is read from command-line arguments and environment variables, and cached responses remain in process memory.

These are properties of the application, not an operating-system sandbox. The process still uses its configured stdio or HTTP transport and the host's normal DNS, proxy, TLS, and HTTP redirect behavior. Run it with least-privilege OS or container permissions when stronger isolation is required.

Cache

Successful deps.dev responses are stored in a concurrency-safe, process-local LRU cache. The default capacity is 256 entries. Set it with either the command line flag or environment variable:

depsdevmcp -cache-capacity 512
DEPSDEVMCP_CACHE_CAPACITY=512 depsdevmcp

Each result contains a cached boolean. Errors are never cached. The cache has no TTL and is cleared when the process exits.

Run locally

Go 1.25 or newer is required because the MCP SDK requires it.

go build -o depsdevmcp ./cmd/depsdevmcp
# stdio transport (default)
./depsdevmcp

# stateless streamable HTTP
./depsdevmcp -transport http

The default HTTP endpoint is http://127.0.0.1:8080/mcp. Configure it with:

| Flag | Environment variable | Default | | --- | --- | --- | | -transport | DEPSDEVMCP_TRANSPORT | stdio | | -http-address | DEPSDEVMCP_HTTP_ADDRESS | 127.0.0.1:8080 | | -http-path | DEPSDEVMCP_HTTP_PATH | /mcp | | -cache-capacity | DEPSDEVMCP_CACHE_CAPACITY | 256 |

Streamable HTTP is stateless so it can negotiate MCP 2026-07-28. The shared deps.dev LRU cache remains process-wide across requests.

For remote deployments, put the endpoint behind an authenticating TLS reverse proxy. The server has no built-in authentication and deliberately binds only to loopback by default. Cross-origin browser requests and localhost DNS-rebinding attempts are rejected.

Stdio client configuration

Example MCP client configuration:

{
  "mcpServers": {
    "deps.dev": {
      "command": "/absolute/path/to/depsdevmcp",
      "args": ["-cache-capacity", "256"]
    }
  }
}

Run with Docker

Stdio:

docker build -t depsdevmcp .
docker run --rm -i depsdevmcp

Streamable HTTP, exposed only on the host loopback interface:

docker run --rm \
  -p 127.0.0.1:8080:8080 \
  depsdevmcp \
  -transport http \
  -http-address 0.0.0.0:8080

Connect an HTTP-capable MCP client to http://127.0.0.1:8080/mcp.

Example MCP client configuration using the published GHCR image:

{
  "mcpServers": {
    "deps.dev": {
      "command": "docker",
      "args": [
        "run",
        "--rm",
        "-i",
        "ghcr.io/mappedsky/depsdevmcp:main"
      ]
    }
  }
}

The GitHub workflow builds linux/amd64 and linux/arm64 images. Pushes to main and v* tags publish to ghcr.io/<owner>/<repository>; pull requests only build the image. All workflow actions are pinned to immutable commit SHAs.

Query examples

Package version query:

{
  "query": "versionKey.system=NPM&versionKey.name=react&versionKey.version=18.2.0"
}

Artifact hash query:

{
  "query": "hash.type=SHA1&hash.value=ulXBPXrC%2FUTfnMgHRFVxmjPzdbk%3D"
}

Dependency path query:

{
  "system": "pypi",
  "name": "botocore",
  "version": "1.34.100",
  "target": "urllib3"
}

The path tool returns one chain per distinct target version, including the requirement on every edge. An absent target is a successful result with pulls_in: false and an explanatory note. Resolved graphs are available for npm, Cargo, Maven, and PyPI.