Pare Configuration Reference

New to Pare? Start with the Quickstart Guide for initial setup. This page covers advanced configuration.

Pare servers are configured via environment variables. All controls are opt-in — by default, no restrictions are applied.

Tool Filtering

Control which tools are available to MCP clients.

PARE_TOOLS

Universal filter across all servers. Comma-separated server:tool pairs.

PARE_TOOLS=git:status,git:log,npm:install

When set, only the listed tools are registered. All others are hidden from MCP clients.

PARE_{SERVER}_TOOLS

Per-server filter. Comma-separated tool names.

PARE_GIT_TOOLS=status,log,diff
PARE_NPM_TOOLS=install,run,test

PARE_TOOLS (global) takes precedence over profiles and per-server variables when both are set.

When neither is set, all tools are enabled (default).

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Tool Profiles (PARE_PROFILE)

Activate a preset collection of tools for common workflows instead of listing individual tools.

PARE_PROFILE=python

Profile	Tools	Description
minimal	18	Core git, build, test, search, and GitHub basics
web	~65	Full-stack web dev: npm, build, lint, test, HTTP
python	~48	Python ecosystem: pip, ruff, mypy, pytest, uv
devops	~59	Docker, K8s, security scanning, CI/CD, releases
rust	~44	Cargo toolchain: build, test, clippy, audit
go	~44	Go toolchain: build, test, vet, lint
full	all	No filtering (default when unset)

Precedence

1. PARE_TOOLS — highest priority (explicit tool list)
2. PARE_PROFILE — preset profile
3. PARE_{SERVER}_TOOLS — per-server filter
4. No env vars — all tools enabled

PARE_PROFILE overrides per-server variables but is itself overridden by PARE_TOOLS. Profile names are case-insensitive.

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Lazy Tool Loading (PARE_LAZY)

By default, every server registers all of its tools at startup. For servers with many tools, this can increase the token cost of the initial tool schema sent to LLM clients. Lazy mode defers non-essential tools so they load on demand.

PARE_LAZY=true npx @paretools/git

When PARE_LAZY=true is set, each server only registers its core tools at startup. Extended tools are held back and made available through a discover-tools meta-tool that is automatically added to every server.

How it works

1. Startup -- Core tools (the most commonly used tools per server) are registered immediately.
2. Discovery -- The discover-tools tool is registered on the server. Calling it lists all available but not-yet-loaded tools.
3. Loading -- Pass tool names to the load parameter of discover-tools to register them on demand. Clients receive a notifications/tools/list_changed notification and re-fetch the tool list.

Core tools per server

Each server defines a set of core tools that always load, even in lazy mode. For example:

Server	Core Tools
git	status, log, diff, commit, push, pull, checkout, branch, add
github	pr-view, pr-list, pr-create, pr-checks, issue-view, issue-list, issue-create
npm	install, run, test, audit, list
build	tsc, build
test	run, coverage
docker	ps, build, logs, images, compose-up, compose-down

The full core tool map is defined in packages/shared/src/profiles.ts.

The discover-tools meta-tool

When lazy mode is active and a server has deferred tools, a discover-tools tool is automatically registered.

Input:

Parameter	Type	Required	Description
load	string[]	No	Tool names to load immediately

Output:

{
  "available": [
    { "name": "rebase", "description": "Rebases the current branch onto a target branch..." },
    { "name": "bisect", "description": "Binary search for the commit that introduced a bug..." }
  ],
  "loaded": ["cherry-pick"],
  "totalAvailable": 2
}

• available -- Tools that are still deferred and can be loaded.
• loaded -- Tools that were just loaded in this call (via the load parameter).
• totalAvailable -- Count of remaining deferred tools after any loads.

Calling discover-tools with no arguments simply lists what is available. Passing load: ["rebase", "bisect"] immediately registers those tools on the server.

Overrides

Lazy mode is automatically disabled when:

• PARE_TOOLS is set -- Explicit tool lists already provide precise control.
• PARE_PROFILE=full is set -- The "full" profile means all tools should load.

Per-server tool filters (PARE_{SERVER}_TOOLS) are applied before lazy mode, so filtered-out tools are never registered regardless of lazy mode.

Configuration example

{
  "mcpServers": {
    "pare-git": {
      "command": "npx",
      "args": ["-y", "@paretools/git"],
      "env": {
        "PARE_LAZY": "true"
      }
    }
  }
}

---

Security Hardening

Opt-in controls that restrict what commands can be executed and where tools can operate. These are designed for deployments where agents may operate in less-trusted environments.

Command Allowlists

Restrict which commands a server can execute.

Variable	Scope	Example
PARE_ALLOWED_COMMANDS	All servers	node,python,git,npm
PARE_{SERVER}_ALLOWED_COMMANDS	Single server	PARE_PROCESS_ALLOWED_COMMANDS=node,python,make

When set, only listed commands may be executed. Commands are matched by basename (e.g., /usr/bin/node matches node). When unset, no restriction.

Global (PARE_ALLOWED_COMMANDS) takes precedence over per-server variables.

Example — restrict the process server to safe commands:

PARE_PROCESS_ALLOWED_COMMANDS=node,python,make,cargo,go

Root Confinement

Restrict which directories tools can operate in.

Variable	Scope	Example
PARE_ALLOWED_ROOTS	All servers	/home/user/projects,/tmp/builds
PARE_{SERVER}_ALLOWED_ROOTS	Single server	PARE_PROCESS_ALLOWED_ROOTS=/home/user/safe-dir

When set, all path/cwd parameters must resolve to a location under one of the listed roots. Paths are normalized and resolved to absolute before comparison. When unset, no restriction.

Global (PARE_ALLOWED_ROOTS) takes precedence over per-server variables.

Example — confine all servers to a project directory:

PARE_ALLOWED_ROOTS=/home/user/myproject

Build Strict Path Mode

Reject path-qualified commands in the build server.

Variable	Value	Effect
PARE_BUILD_STRICT_PATH	true	Rejects commands containing / or \ (e.g., /tmp/evil/npm)
(unset)	—	Current behavior: basename-only validation with warning for path-qualified commands

This prevents a class of attack where a malicious binary is placed at a trusted-name path. When enabled, only bare command names resolved via PATH are accepted.

PARE_BUILD_STRICT_PATH=true

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Error Output Sanitization

PARE_SANITIZE_ALL_PATHS

Broaden path redaction in error output beyond home directories.

Variable	Value	Effect
PARE_SANITIZE_ALL_PATHS	true	Redacts absolute paths under /etc, /var, /opt, /usr, /tmp, /srv, /snap, /nix, and non-user Windows paths
(unset)	—	Only home directory paths are redacted (default)

Default behavior replaces /home/<user>/... → ~/... and similar patterns. Broad mode additionally replaces other absolute paths with <redacted-path>/filename, preserving the basename while hiding directory structure.

PARE_SANITIZE_ALL_PATHS=true

---

Precedence Rules

All global/per-server variables follow the same precedence:

1. Global (PARE_{SETTING}) — applies to all servers, highest priority
2. Per-server (PARE_{SERVER}_{SETTING}) — applies to one server only
3. No variable set — permissive default (no restriction)

Server names in env vars use uppercase with hyphens replaced by underscores:

• server-git → PARE_GIT_*
• server-process → PARE_PROCESS_*
• server-security → PARE_SECURITY_*

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Quick Reference

Variable	Type	Default	Description
PARE_TOOLS	server:tool,...	all enabled	Global tool filter
PARE_PROFILE	profile name	full	Preset tool profile
PARE_{SERVER}_TOOLS	tool,...	all enabled	Per-server tool filter
PARE_LAZY	true	disabled	Defer non-core tools; load via discover-tools
PARE_ALLOWED_COMMANDS	cmd,...	unrestricted	Global command allowlist
PARE_{SERVER}_ALLOWED_COMMANDS	cmd,...	unrestricted	Per-server command allowlist
PARE_ALLOWED_ROOTS	path,...	unrestricted	Global root confinement
PARE_{SERVER}_ALLOWED_ROOTS	path,...	unrestricted	Per-server root confinement
PARE_BUILD_STRICT_PATH	true	disabled	Reject path-qualified build commands
PARE_SANITIZE_ALL_PATHS	true	disabled	Broad absolute path redaction