dart_pubdev_mcp 0.6.3

Model Context Protocol (MCP) server for pub.dev. Gives AI agents structured access to search, compare, evaluate, and inspect Dart and Flutter packages.

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

Agents without this server tend to guess package names, hallucinate APIs, or paste in stale advice from training data. dart-pubdev-explorer backs every answer with a live call to pub.dev, dartdoc, or the package tarball itself, so an agent's answer is grounded instead of guessed.

Features

• Find the right package. search_packages ranks by relevance, likes, pub points, or recency, filtered by SDK and platform.
• Read the real docs. Full READMEs, examples, changelogs, and pubspec.yaml, fetched at the exact version being targeted.
• Browse the API like a human would. Search a package's public symbols by name or keyword, then read full signatures, doc comments, and every throw site.
• Read exact source. Pull a file by line range or by symbol name — resolved through the analyzer AST — without downloading and unpacking a tarball by hand.
• Compare candidates side by side. Score, platform support, and maintenance signals for 2–5 packages in one call.
• Plan upgrades with confidence. Structured changelog entries flagged breaking, plus a symbol-level diff between any two versions.

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

Add a stdio server entry pointing at the installed executable. For example, in Claude Code / Claude Desktop's .mcp.json:

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

Any MCP client that speaks stdio works the same way — Cursor, Windsurf, Zed, and others follow the same shape, a bare command with no arguments required. Pass any of the CLI flags below in args if you need non-default behavior.

3. Try it

Once connected, ask your agent something that needs live package data instead of training-data guesses, for example:

"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.

Tools

All tools return JSON. Every tool that accepts a package version omits it to resolve the latest stable release, and the response then carries a resolvedVersion field naming what was actually used. Every tool but search_packages also declares an outputSchema and returns a matching structuredContent block alongside its text response, for clients that validate against a typed contract.

Tool	Purpose	Key parameters
search_packages	Find packages by keyword; the usual starting point.	query (required); limit (1–20, default 5); page; sdk (dart|flutter); platform (android|ios|web|linux|macos|windows); sort (relevance|likes|pub_points|updated)
get_package	Full metadata for one package — score, SDK constraints, dependency count.	package (required); version (omit for latest)
compare_packages	Side-by-side score/platform/maintenance matrix for 2–5 candidates.	packages (required, 2–5 entries)
list_package_versions	All published versions, bucketed into stable/prerelease/retracted with publish dates.	package (required)
get_changelog	Structured changelog entries with a breaking flag per entry.	package (required); fromVersion (skip already-known entries); limit (default 5)
get_api_diff	Symbols added/removed between two versions (presence-based, not signature diffs).	package, fromVersion, toVersion (all required)
browse_api_symbols	Substring lookup over the dartdoc symbol index, narrowable by kind (class/method/enum/etc.); use find_symbols for fuzzy, multi-token discovery.	package, query (required); kind (class/method/enum/etc.); limit (1–25, default 10); version
find_symbols	Fuzzy, multi-token discovery over the same symbol index as browse_api_symbols (order-independent), capped at 20 results; no kind filter.	package, query (required); version
get_symbol_documentation	Full signature and doc comment for a known symbol (short name or qualified, e.g. Client.send).	package, symbol (required); version
get_throw_statements	Every throw in a class or method, with surrounding control-flow context.	package (required); class; method (at least one of class/method required); version
get_source_slice	Read source from one file — by line range, or by symbol name via the analyzer AST.	package, file (required); version; lineStart/lineEnd; symbolName; maxLines (collapse large symbols)
list_package_source_files	Browse a package's file tree, filtered by directory prefix and/or extension.	package (required); version; directory; fileExtension
get_sdk_source_slice	Read Dart SDK (dart:core, dart:async, …) or Flutter SDK/framework (package:flutter, flutter_test, …) source — by line range, or by symbol name via the analyzer AST — not published on pub.dev, so get_source_slice can't reach it.	sdk, file (required); library (Dart) or package (Flutter), whichever sdk selects; version (defaults to the running Dart SDK version, or the local Flutter install's framework version); lineStart/lineEnd; symbolName; maxLines (collapse large symbols)
list_sdk_source_files	Browse the Dart SDK's or Flutter SDK/framework's file tree, filtered by library (Dart) or package (Flutter).	sdk (required); library (Dart) or package (Flutter), whichever sdk selects — omit either to list every file; version (defaults as get_sdk_source_slice does)
get_sdk_throw_statements	Every throw in a class or method within the Dart SDK or Flutter SDK/framework — the SDK-source counterpart to get_throw_statements.	sdk (required); library (Dart) or package (Flutter), whichever sdk selects; class; method (at least one of class/method required); version (defaults as get_sdk_source_slice does)

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).

Typical flows

• Discovery: search_packages → get_package → the readme resource for full setup docs.
• API exploration: get_symbol_documentation directly if the symbol name is known, otherwise browse_api_symbols or find_symbols to locate it → get_throw_statements → get_source_slice if more implementation detail is needed.
• Upgrade analysis: get_changelog with fromVersion set → check breaking flags → get_api_diff for the precise symbol-level delta.
• Choosing between packages: search_packages → compare_packages on the top candidates.
• SDK exploration: list_sdk_source_files to discover a file path when unknown → get_sdk_throw_statements for exception surface → get_sdk_source_slice for implementation detail.

Resources

In addition to tools, the server exposes read-only MCP resources. Read pub://meta/resources first to get the full manifest as JSON.

URI	Content
pub://meta/resources	Manifest of every resource URI, MIME type, and description.
pub://meta/instructions	The same server instructions sent during the MCP handshake — re-read it if a workflow feels off.
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}/example	Working example code from the package's Example tab (Markdown).
pub://package/{name}@{version}/changelog	Full raw changelog text (Markdown) — prefer the get_changelog tool for structured entries.
pub://package/{name}@{version}/api	Raw dartdoc symbol index (JSON) — prefer browse_api_symbols/find_symbols for filtered lookup.
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.