golang-pkg-go-dev

# golang-pkg-go-dev

**Dependencies:** `godig` — `go install github.com/samber/godig/cmd/godig@latest` (or use a registered godig MCP server / the hosted instance instead).

`godig` queries the [pkg.go.dev](https://pkg.go.dev) API. Use it to answer questions about Go packages and modules: docs, symbols, versions, importers and vulnerabilities. It works as a CLI and as an MCP server. All operations are **read-only** and need no authentication.

## When to use this skill

Trigger on questions like:

- "What versions of github.com/samber/lo are available?"
- "Does golang.org/x/text have known vulnerabilities?"
- "Show me the docs / symbols for package X."
- "Which packages import X?"
- "Search Go packages for Y."

## Setup

### Install

```bash
go install github.com/samber/godig/cmd/godig@latest
```

### Register the MCP server (optional)

`godig mcp` runs over **stdio** by default, or **streamable HTTP** with `--transport http`.

stdio (the client launches godig on demand):

```bash
claude mcp add pkg-go-dev -- godig mcp
```

streamable HTTP (shared server at `/mcp`, default `:8080`):

```bash
godig mcp --transport http --addr :8080
claude mcp add --transport http pkg-go-dev http://localhost:8080/mcp
```

Hosted instance (no install needed) — a public server runs at `https://godig.samber.dev/mcp`:

```bash
claude mcp add --transport http pkg-go-dev https://godig.samber.dev/mcp
```

The CLI and the MCP server expose the **same** operations under matching names. Prefer the CLI when `godig` is installed; the hosted instance is a fallback when it is not.

## Commands

**Global flags (all commands):** `-o/--output table|json|raw|md` (default `table` — pass `-o md` for chat), `--base-url`, `--timeout`, `--log-level debug|info|warn|error|off`. All are also settable via `GODIG_*` env vars.

| Command | Args | Specific flags | Purpose |
| --- | --- | --- | --- |
| `overview` | `<path>` | `--version` | Compact summary (metadata, versions, licenses, vulns) — start here |
| `search` | `<query>` | `--symbol --limit --filter` | Find packages (optionally exporting a symbol) |
| `package info` | `<path>` | `--module --version` | Package metadata |
| `package imports` | `<path>` | `--module --version` | Packages this package imports (plain list) |
| `package doc` | `<path>` | `--module --version --goos --goarch --format md\|text\|html\|markdown` | Full package doc (LARGE) |
| `package examples` | `<path>` | `--module --version --goos --goarch --symbol` | Runnable examples (LARGE; scope with `--symbol`) |
| `package licenses` | `<path>` | `--module --version` | License files, full text (LARGE) |
| `symbol doc` | `<path> <symbol>` | `--module --version --goos --goarch` | One symbol's signature + doc (token-efficient) |
| `symbol examples` | `<path> <symbol>` | `--module --version --goos --goarch` | One symbol's runnable examples |
| `symbols` | `<path>` | `--module --version --goos --goarch --limit --filter` | List exported symbols |
| `module info` | `<path>` | `--version` | Module metadata |
| `module licenses` | `<path>` | `--version` | Module license files (LARGE) |
| `module readme` | `<path>` | `--version` | Module README, full Markdown (LARGE) |
| `dependencies` | `<path>` | `--version` | go.mod deps: requires / replaces / excludes / go directive |
| `packages` | `<path>` | `--version --limit --filter` | Packages contained in a module |
| `versions` | `<path>` | `--limit --filter` | All versions, newest first |
| `major-versions` | `<path>` | `--limit --filter --exclude-pseudo` | Major versions (v1, v2 …) living as separate modules |
| `imported-by` | `<path>` | `--module --version --limit --filter` | Packages that import this one |
| `vulns` | `<path>` | `--module --version --limit --filter` | Known vulnerabilities |
| `mcp` | — | `--transport stdio\|http --addr --cache-ttl --cache-size` | Run as an MCP server |
| `version` | — | — | Print godig version / commit / build date |

When `godig` runs as an MCP server, each data command above is exposed as an operation of the same name.

**Exit codes:** `0` success, `1` runtime error (network, package not found), `2` usage error — a missing/invalid argument or flag (e.g. a non-positive `--limit`), or a command group invoked with no subcommand (`godig package`). Check for `2` to tell a malformed call apart from a failed lookup.

Full `-o md` output for every command: [sample-output.md](references/sample-output.md).

### Tips

- **Start with `overview`** — one call returns a compact summary (metadata, latest + recent versions, license types, vulnerabilities). Reach for `doc`/`examples`/`module readme`/`licenses` (LARGE) only when the full text is needed.
- **Always pass `-o md`** so results render as Markdown (tables, or raw doc/README) in the chat. Other formats exist (`table` default, `json`, `raw`) but prefer `md` here.
- `<path>` is a full import path, e.g. `github.com/samber/lo` — pass it as the positional argument.
- `--version` pins a specific module version (`v1.5.0`, `latest`, `master`, `main`); `--module` disambiguates which module a package belongs to.
- `--filter` narrows list results server-side with a Go boolean expression — see [Filter syntax](#filter-syntax).
- `--goos`/`--goarch` set the documentation/symbols build context (e.g. `linux`/`amd64`).
- Prefer `symbol doc`/`symbol examples` over the package-wide `package doc`/`package examples` when you only need one symbol — far fewer tokens.
- **Parallelize independent lookups** — every command is a self-contained, read-only HTTP query, so calls never depend on each other. When a task needs docs, examples, versions, or vulns for **several** symbols, packages, or modules, issue all the calls at once (multiple `godig` invocations in a single turn) rather than one after another — wall-clock drops from sum-of-latencies to slowest-single-call. For a large fan-out (documenting many symbols, comparing many candidate libraries, auditing CVEs across a dependency set), dispatch parallel sub-agents (up t