dart-pubdev-explorer #

Ships as the dart_pubdev_mcp package on pub.flutter-io.cn; 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.flutter-io.cn 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.flutter-io.cn, 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.
• grep_package_source — search across a package's whole source tree for a literal string or regex pattern, so an agent can find every call site of a symbol without enumerating and reading files one by one.

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 / grep_sdk_source — the same source-reading, throw-site, and search tools, but for the Dart SDK (dart:core, dart:async, …) and Flutter framework (package:flutter, …), which live outside pub.flutter-io.cn and are otherwise invisible to an agent. grep_sdk_source scans .dart files only by default, since an SDK or framework tarball is far noisier with non-Dart content than a pub.flutter-io.cn package.

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.

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.

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.