spm-search-mcp

An MCP server that lets coding agents search the Swift Package Index. No API key required.

Built with FastMCP and designed using arcade patterns for optimal agent comprehension.

Note (March 2026): This project is currently on hold. It was built as a proof-of-concept for agentic SPI search using HTML scraping and a Cloudflare bypass (curl_cffi). The bypass has since been removed — the project now uses plain httpx and no longer attempts to circumvent bot protection, which means it is effectively non-functional. See SwiftPackageIndex/SwiftPackageIndex-Server#3970 for context. The project will resume if/when an official API becomes available.

Quick install

From the repo root, run the command for your MCP client:

# Claude Desktop
fastmcp install claude-desktop src/spm_search_mcp/server.py:mcp --with-editable . -n "Swift Package Index"

# Claude Code
fastmcp install claude-code src/spm_search_mcp/server.py:mcp --with-editable . -n "Swift Package Index"

# Cursor
fastmcp install cursor src/spm_search_mcp/server.py:mcp --with-editable . -n "Swift Package Index"

# Any client — print the JSON snippet to paste
fastmcp install mcp-json src/spm_search_mcp/server.py:mcp --with-editable . -n "Swift Package Index"

Manual MCP client configuration

Via GitHub (no install needed)

// add to your mcpServers:
"spm-search-mcp": {
  "command": "uvx",
  "args": [
    "--from", "git+https://github.com/detailobsessed/spm-search-mcp",
    "spm-search-mcp"
  ]
}

Requires uv (brew install uv on macOS).

From source (development)

// add to your mcpServers:
"spm-search-mcp": {
  "command": "uv",
  "args": [
    "run",
    "--with", "fastmcp",
    "--with-editable", "/path/to/spm-search-mcp",
    "fastmcp", "run",
    "/path/to/spm-search-mcp/src/spm_search_mcp/server.py:mcp"
  ]
}

Tools

search_swift_packages

Search for Swift packages by keyword, author, stars, platform, license, and more. All of SPI's filter syntax is exposed as typed parameters — agents never need to learn the DSL.

All parameters are optional. At least one must be provided. Parameters combine with AND logic.

list_search_filters

Returns valid values for the platforms and product_type parameters. Call this first if unsure what values are accepted.

No parameters. Returns a dict with platforms and product_types keys.

get_package_readme

Fetch a package's README from GitHub. Returns truncated content by default (4000 chars) to save tokens.

Example usage

Once connected, an agent can:

# Search for networking libraries with 500+ stars
search_swift_packages(query="networking", min_stars=500)

# Find iOS-compatible packages
search_swift_packages(platforms=["ios"], min_stars=100)

# Discover valid platform and product_type values
list_search_filters()

# Browse a specific author's packages
search_swift_packages(author="apple")

# Exclude an author
search_swift_packages(query="networking", author="!vapor", min_stars=500)

# Exclude deprecated packages
search_swift_packages(query="json", keyword="!deprecated")

# Packages active in a date window (first half of 2024)
search_swift_packages(last_activity_after="2024-01-01", last_activity_before="2024-06-30", min_stars=100)

# Find abandoned packages (no commits since 2022)
search_swift_packages(last_commit_before="2022-01-01", min_stars=200)

# Read a package's README
get_package_readme(owner="Alamofire", repo="Alamofire")

# Get full README (no truncation)
get_package_readme(owner="apple", repo="swift-nio", max_length=0)

Error handling

All errors return structured, actionable messages instead of raw exceptions:

• RETRYABLE — transient failures (timeouts, rate limits, server errors). The agent can retry.

• PERMANENT — the request itself is wrong (404, 403). The agent should change its approach.

Every error message tells the agent what happened, why, and how to fix it.

Design

This server implements these arcade patterns:

• QUERY_TOOL — all tools are read-only, safe to retry

• DISCOVERY_TOOL — list_search_filters() exposes valid enum values before searching

• CONSTRAINED_INPUT — enums for platforms and product types

• SMART_DEFAULTS — all parameters optional with sensible defaults

• NEXT_ACTION_HINT — every response suggests what to do next

• GUI_URL — every result includes SPI + GitHub URLs

• TOKEN_EFFICIENT_RESPONSE — truncated README with opt-in full

• PAGINATED_RESULT — has_more flag with page navigation

• ERROR_CLASSIFICATION — RETRYABLE vs PERMANENT error tagging

• RECOVERY_GUIDE — actionable error messages with fix instructions

• PROGRESSIVE_DETAIL — max_length=0 for full README content

Development

uv sync                  # install dependencies
uv run pytest            # run tests
uv run poe test-cov      # run with coverage (90%+ required)
uv run ruff check .      # lint
uv run ty check .        # type check
prek run --all-files     # run all pre-commit hooks