dart-pubdev-explorer

Ships as the dart_pubdev_mcp package on pub.dev; the server and CLI identify themselves as dart-pubdev-explorer.

A Model Context Protocol server that gives AI coding agents structured, version-aware access to the pub.dev Dart and Flutter package registry. Instead of scraping HTML, guessing package names, or repeating stale advice from training data, an agent can search, compare, and read packages — down to an exact source line — the way a careful maintainer would.

Why it exists

Without live registry access, agents tend to:

• Recommend deprecated or unmaintained packages.
• Invent API method signatures that don't exist, or that changed versions ago.
• Miss breaking changes between the version they trained on and the version installed.
• Have no access at all to Dart/Flutter SDK framework source.

dart-pubdev-explorer backs every answer with a live call to pub.dev, dartdoc, or the package tarball itself, so the agent's answer is grounded instead of guessed.

For example, ask:

"Compare dio and http for a Flutter app that needs file uploads — which has better platform support and is more actively maintained?"

The agent resolves this itself: search_packages to confirm both names exist, compare_packages for the side-by-side score/platform/maintenance matrix, then get_symbol_documentation if it needs to check a specific API before recommending one.

Quick start

1. Install

Requires the Dart SDK (>=3.9.0).

dart install dart_pubdev_mcp

This installs the dart-pubdev-explorer executable onto your PATH. Verify with:

dart-pubdev-explorer --version

To upgrade later, re-run dart install dart_pubdev_mcp (add --overwrite if another package has already claimed the dart-pubdev-explorer executable name).

2. Configure your MCP client

All clients run the same stdio command with no arguments — only the config shape differs.

Claude Code (CLI)

claude mcp add dart-pubdev-explorer -- dart-pubdev-explorer

Cursor / VS Code / Antigravity / Windsurf (.mcp.json)

{
  "mcpServers": {
    "dart-pubdev-explorer": {
      "command": "dart-pubdev-explorer"
    }
  }
}

Zed (settings.json)

{
  "context_servers": {
    "dart-pubdev-explorer": {
      "command": {
        "path": "dart-pubdev-explorer"
      }
    }
  }
}

Pass any of the CLI flags below as extra args if you need non-default behavior (custom cache directory, verbose logging, etc.).

3. Try it

Once connected, ask your agent something that needs live package data instead of a training-data guess:

• "Find actively maintained Flutter state-management packages with web and iOS support."
• "Compare dio and http for file upload support, popularity, and pub points."
• "Show the signature and doc comment for http.Client.send."
• "List the breaking changes in go_router between 12.0.0 and 14.0.0."
• "Show how StreamController handles cancellation in dart:async."

Tools

All tools return JSON and resolve to the latest stable version when version is omitted.

Package discovery and evaluation

• search_packages — find packages by keyword, filtered by SDK, platform, and sort order. Your starting point for "what should I use for X."
• get_package — full metadata for one package: score, SDK constraints, dependencies.
• compare_packages — score/platform/maintenance side by side for 2–5 candidates, so an agent can justify a recommendation instead of asserting it.
• list_package_versions — every published version, bucketed into stable/prerelease/retracted.
• get_security_advisories — known security advisories for a package, evaluated against a specific version so the agent knows whether that version is actually affected, not just whether the package has ever had one.

API and source inspection

• browse_api_symbols / find_symbols — search a package's public API by substring or fuzzy keyword, so the agent finds the real symbol before it writes code against it.
• get_symbol_documentation — the actual signature and doc comment for a symbol, instead of a remembered (and possibly outdated) one.
• get_throw_statements — every throw in a class or method, so the agent can write correct try/catch handling instead of guessing at exception types.
• get_source_slice — exact source, by line range or by symbol name, resolved through the analyzer AST — no manual tarball download required.
• list_package_source_files — browse a package's file tree to find examples or implementation files.

Version diffs and upgrades

• get_changelog — structured changelog entries with a breaking flag, so an agent can tell you what actually changed instead of paraphrasing prose.
• get_api_diff — symbols added or removed between two versions, for upgrade-safety checks before bumping a dependency.

SDK internals

• list_sdk_source_files / get_sdk_source_slice / get_sdk_throw_statements — the same source-reading and throw-site tools, but for the Dart SDK (dart:core, dart:async, …) and Flutter framework (package:flutter, …), which live outside pub.dev and are otherwise invisible to an agent.

Errors from any tool carry a machine-readable code and a suggestion field describing the next step (e.g. AMBIGUOUS_SYMBOL includes candidate qualified names to retry with).

Resources

In addition to tools, the server exposes read-only MCP resources — raw README/changelog/pubspec/example content, plus a couple of reference docs. Read pub://meta/resources for the full manifest.

URI	Content
pub://meta/resources	Manifest of every resource URI, MIME type, and description.
pub://meta/scoring	Plain-text explainer of pub.dev's 160-point scoring rubric.
pub://meta/sdk-versions	Current stable Dart and Flutter SDK versions as JSON.
pub://package/{name}@{version}/readme	Full README (Markdown).
pub://package/{name}@{version}/changelog	Full raw changelog text (Markdown).
pub://package/{name}@{version}/example	Working example code from the package's Example tab (Markdown).
pub://package/{name}@{version}/pubspec	Verbatim pubspec.yaml from the version's tarball.

Package resource URIs require an explicit @{version} segment; use @latest to resolve the latest stable release.

Configuration

All settings are optional; CLI flags take precedence over environment variables, which take precedence over defaults.

Flag	Environment variable	Default	Purpose
--log-level <level>	dart_pubdev_mcp_LOG_LEVEL	warning	Minimum log severity: debug|info|warning|error.
--cache-dir <path>	dart_pubdev_mcp_CACHE_DIR	$XDG_CACHE_HOME/dart_pubdev_mcp or ~/.cache/dart_pubdev_mcp	Directory for the on-disk tarball cache.
--max-cache-size <size>	dart_pubdev_mcp_MAX_CACHE_SIZE	500 MiB	Total cap on the tarball disk cache. Accepts bytes or KB/MB/GB/KiB/MiB/GiB suffixes.
--max-concurrent-requests <count>	dart_pubdev_mcp_MAX_CONCURRENT_REQUESTS	5	Cap on simultaneous in-flight pub.dev HTTP requests (1–64).
--wire-trace	dart_pubdev_mcp_WIRE_TRACE	off	Enable a human-readable diagnostic log of every outbound HTTP request/response.
--wire-trace-dir <path>	dart_pubdev_mcp_WIRE_TRACE_DIR	<cache-dir>/wire-trace	Directory for per-session Wire Trace files.
--wire-trace-max-preview <bytes>	dart_pubdev_mcp_WIRE_TRACE_MAX_PREVIEW	2048	Cap on each logged response body preview; 0 logs metadata only.
--no-update-check	dart_pubdev_mcp_UPDATE_CHECK	on	Disable the startup Update Check against pub.dev for this server's own version.

Run dart-pubdev-explorer --help for the same reference from the CLI, or dart-pubdev-explorer --version to print the installed version.

How this compares

The official Dart MCP server (dart mcp-server) ships a general pub_dev_search tool alongside its much broader Dart/Flutter tooling surface — running apps, analysis, DTD, and more. dart-pubdev-explorer is a focused, deeper tool for package research specifically: symbol-level API browsing, exact source reads, multi-version diffing, and side-by-side comparison, backed by an on-disk cache tuned for the repeated lookups a single research session tends to make. The two are complementary — run both.

Contributing

Source, issues, and the changelog live in the agentic_dart monorepo, under packages/dart_pubdev_mcp. Bug reports and pull requests are welcome via the issue tracker.

License

MIT License — see LICENSE.