mcp-methods 0.3.26

Reusable utility methods for MCP servers

mcp-methods

Shared Rust-powered utilities for MCP servers. Pip-installable Python library AND a native Rust crate — they're the same set of primitives reachable through whichever interface fits your project. Fast file search, GitHub integration, text compaction, and an rmcp-backed MCP server framework. The common building blocks needed when writing MCP tool servers.

The Rust library is the source of truth; the Python wheel is a thin PyO3 binding over it. Rust consumers see zero Python in their dep tree.

Install — Python

pip install mcp-methods

from mcp_methods import ElementCache, ripgrep, list_dir, github_issues, read_file, html_to_text

Single abi3 wheel per OS — works on Python 3.10 through 3.13 without reinstall.

Install — Rust library

[dependencies]
mcp-methods = "0.3"

use mcp_methods::cache::ElementCache;
use mcp_methods::{github, files, grep, list_dir, compact, html};
use mcp_methods::server::{McpServer, ServerOptions, Manifest}; // with default `server` feature

Zero pyo3 in the dep tree. The server feature (default-on) adds the rmcp-backed framework; disable with default-features = false for the bare primitives.

Install — mcp-server CLI

cargo install mcp-server

Generic MCP server binary that loads YAML manifests and serves the protocol over stdio. Separate crate; not bundled in the Python wheel.

Local development

make dev           # build + install editable wheel
make test          # python tests
make test-rust     # rust library tests
make test-rust-all # all workspace tests

What's included

Function	Purpose
list_dir	Tree-formatted directory listing with depth control, glob filtering, .gitignore support, dir summaries, and annotation callback
ripgrep_files	Ripgrep-powered file search with parallel walking, early termination, context lines, and multiple output modes
ripgrep	Drop-in replacement for the Claude Code Grep tool interface
read_file	Safe file reading with path traversal protection and line range support
github_discussions	Fetch a single issue/PR with smart compaction, or list issues/PRs with filters
git_api	GitHub REST API wrapper with token auth
has_git_token	Returns whether a usable GITHUB_TOKEN is reachable (used for honest tool listing)
ElementCache	Drill-down cache for collapsed elements (code blocks, comments, patches, thread segments) in GitHub discussions
html_to_text	Lightweight HTML → plain-text converter (markdown-flavoured)
ripgrep_lines	Search through text lines with context window merging
ripgrep_json_fields	Extract fields from JSON text
compact_discussion / compact_text / collapse_code_blocks	Text compaction utilities
extract_github_refs	Parse GitHub issue/PR references from text
detect_git_repo / validate_repo	Git repository detection and validation
mcp_methods.fastmcp	Composable tool registrations for FastMCP servers — see below

Python API

list_dir(path, *, depth=1, glob=None, dirs_only=False, relative_to=None, respect_gitignore=True, skip_dirs=None, include_size=False, annotate=None)

Tree-formatted directory listing.

from mcp_methods import list_dir

# Basic tree
tree = list_dir("/project/src", depth=2, glob="*.py", relative_to="/project")

# With annotation callback (e.g. loc from knowledge graph)
def get_loc(rel_path):
    node = graph.get_file(rel_path)
    return f"({node.loc} loc)" if node else None

tree = list_dir("/project/src", depth=2, annotate=get_loc)
# src/
# ├── main.py        (144 loc)
# ├── utils.py       (28 loc)
# └── models/
#     ├── user.py    (89 loc)
#     └── post.py    (112 loc)

ripgrep(pattern, *, path=".", glob="*", type=None, output_mode="files_with_matches", max_results=None, offset=0, ...)

Claude Code Grep-compatible interface.

from mcp_methods import ripgrep

results = ripgrep(r"def \w+", path="/project", type="py", max_results=50)

ripgrep_files(source_dirs, pattern, *, glob="*", type_filter=None, output_mode="content", max_results=None, offset=0, match_limit=None, relative_to=None, ...)

Full interface with multi-directory search. max_results limits output entries, match_limit caps the search engine for early termination.

from mcp_methods import ripgrep_files

results = ripgrep_files(
    ["/project"],
    r"def \w+",
    type_filter="py",
    relative_to="/project",
    match_limit=500,
    max_results=100,
)

github_discussions(*, repo=None, number=None, kind="all", state="open", sort="created", limit=20, labels=None)

Fetch a single discussion or list discussions.

from mcp_methods import github_discussions, ElementCache

# List open issues
issues = github_discussions(repo="owner/repo", kind="issue", state="open")

# List pull requests
prs = github_discussions(repo="owner/repo", kind="pr", limit=10)

# Fetch a single issue/PR with smart compaction
issue = github_discussions(repo="owner/repo", number=123)

ElementCache — progressive disclosure for GitHub discussions

Cache for drill-down into collapsed elements. Fetches a discussion once, then lets you explore code blocks, comments, and PR diffs without re-fetching.

from mcp_methods import ElementCache

cache = ElementCache()

# First call fetches from GitHub API, compacts, and caches elements
text = cache.fetch_issue("owner/repo", 123)

# Subsequent calls return cached summary (no network)
summary = cache.fetch_issue("owner/repo", 123)
# → "Cached owner/repo#123 — 5 elements available: cb_1, comment_2, patch_1, patch_2, patch_3"

# Force re-fetch when the issue has changed upstream
text = cache.fetch_issue("owner/repo", 123, refresh=True)

# Drill into a collapsed code block
code = cache.retrieve("owner/repo", 123, "cb_1")

# Drill into a PR patch with grep
result = cache.retrieve("owner/repo", 123, "patch_1", grep="error_handler")

# Drill into a patch with line range
result = cache.retrieve("owner/repo", 123, "patch_2", lines="10-30")

# List available elements
ids = cache.available("owner/repo", 123)

PR diffs are automatically collapsed into patch_N elements in the compact view. Each patch stores the filename, additions/deletions, and full diff text — supporting grep and line-range drill-down.

Large discussions (50+ comments) are automatically digested: first 5 + maintainer highlights + last 5 comments shown inline, with the full middle cached as individual comment_N elements and a searchable comments_middle segment.

git_api(repo, path, *, truncate_at=80000)

GitHub REST API wrapper. For comparing branches/tags, use compare:

from mcp_methods import git_api

# Compare two refs
diff = git_api("owner/repo", "compare/main...feature-branch")

# List commits
commits = git_api("owner/repo", "commits?per_page=10")

read_file(path, allowed_dirs, *, offset=0, limit=0, max_chars=0, transform=None)

Safe file reading with path traversal protection.

from mcp_methods import read_file

content = read_file("src/main.py", ["/project"])

mcp_methods.fastmcp — drop-in tools for FastMCP servers

If you're running your own FastMCP server but want the same tool surface the bundled mcp-server binary ships (source navigation, graph overview, Cypher with CSV export, save_graph), import these helpers and register them on your app:

from mcp.server.fastmcp import FastMCP
from mcp_methods.fastmcp import (
    register_overview,
    register_cypher_query,
    register_source_tools,
    register_save_graph,
    serve_csv_via_http,
)

app = FastMCP("My Server")
register_overview(app, graph, overview_prefix="My custom guidance")
register_cypher_query(app, graph, csv_dir="temp/")
register_source_tools(app, source_roots=["./source"])
register_save_graph(app, graph)
_server, base_url = serve_csv_via_http("temp/")  # optional CORS-enabled HTTP server
app.run(transport="stdio")

Each helper is a thin (~10-line) wrapper over the existing Rust PyO3 surface — there's no logic duplication between the YAML-driven binary and these helpers, so agent behaviour is identical regardless of which path booted the server. graph is any object exposing describe() / cypher() / save(); kglite's KnowledgeGraph satisfies it. A runnable end-to-end stub lives at examples/fastmcp_demo.py.

Deployment — mcp-server CLI

Get the binary via crates.io:

cargo install mcp-server
# → ~/.cargo/bin/mcp-server

Generic MCP server, domain-agnostic: source tools + GitHub access + a manifest-driven tool surface. Reads YAML manifests and serves the MCP protocol over stdio.

Downstream Rust crates (e.g. kglite-mcp-server) depend on mcp-methods directly and re-use mcp_methods::server::McpServer::new(...) to layer domain-specific tools on top while reusing the boot sequence, .env loading, workspace mode, and watch mode.

Cargo features

Feature	What it enables	Default
server	The MCP server framework: rmcp + tokio + clap + manifest + tool routing + the mcp_methods::server module tree.	on

PyO3 bindings live in a separate crate (mcp-methods-py) and are only built by maturin for the Python wheel — they don't live in mcp-methods's source or dep tree. cargo add mcp-methods is zero-Python:

# Pure-Rust framework (default):
mcp-methods = "0.3"

# Just the primitives — no rmcp / tokio:
mcp-methods = { version = "0.3", default-features = false }

Operating modes (set via CLI flag or the YAML manifest)

Mode	How to set	When to use
bare	no flag	testing the protocol layer in isolation
source-root	--source-root DIR or YAML source_root:	fixed local directory; no clone
workspace (github)	--workspace DIR	clone-and-track GitHub repos
workspace (local)	YAML workspace: { kind: local, root: ..., watch: ... }	fixed local dir + optional file watcher; alternative to the legacy code_review server
watch	--watch DIR	rebuild downstream artifacts on file changes

YAML manifest declarations win over CLI flags when both are set (same precedence rule as source_root:).

Architecture

All heavy lifting is in Rust (PyO3/maturin), compiled to a native Python extension:

• grep: Uses grep-regex, grep-searcher, and ignore crates directly (not a ripgrep subprocess). Parallel file walking with per-thread searcher reuse, mmap, SIMD literal optimization, and .gitignore support.
• GitHub: HTTP via ureq, JSON processing via serde_json, text compaction in Rust. PR diffs are collapsed into cacheable elements for progressive disclosure.
• File I/O: Path validation and traversal protection in Rust.

License

MIT