Argos

A hundred eyes on your databases, and none of them blink: beside Claude Code, and in front of every query it runs.

Argos Panoptes (Ἄργος Πανόπτης) is the giant of Greek myth with a hundred eyes, set by Hera to guard Io. Only some of his eyes slept at a time, so he was never fully asleep and nothing passed him unseen. Panoptes means "all-seeing".

TL;DR: Argos lets Claude Code query PostgreSQL, MySQL, SQLite and SQL Server through one MCP server. Every request passes validation, access controls and redaction, and leaves an audit record, before it reaches the database. In Claude Code, /argos opens a pane beside your session: your connections and their schema, every query Claude runs with its full result, and an editor for your own queries, which are always read-only.

Argos speaks any MCP client, not just Claude Code, and connects to databases you already run, directly or through an SSH tunnel.

Status: pre-release. Argos is not yet published to npm, and the publish step in the release workflow is deliberately dormant. The source is public on GitHub, so install from source (see Installation). Any npm install -g argos-mcp command you find elsewhere will not resolve yet.

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A Claude Code session: /argos opening the pane, a question about the shop database whose query lands in Queries with its full result, a look at orders in Schema, and the Editor refusing a DELETE on a connection that allows writes.

Features

• The pane: /argos opens your databases beside the chat on four tabs: Queries (every query Claude or you ran, across sessions, with its full result, pins and reruns), Schema (tables with their keys and relations), Editor (your own queries) and Connections
• Pane queries are always read-only: whatever a connection allows Claude, what you run from the pane opens read-only at the database where the engine supports it, behind the same SELECT-only check the server uses
• SELECT-only mode: production-safe read-only access per connection, which the model cannot relax from a session
• Query validation: bound parameters, stacked statements refused, comment- and literal-aware parsing, complexity limits
• Field redaction: emails, phone numbers and other protected columns are masked before a result reaches Claude, or the pane
• Audit logging: one record per query: database, statement hash, duration, outcome, never the values
• Schema changes reach Claude: when a connection's schema changed since Argos last looked, the next query says what changed, so Claude doesn't work from an old picture of the tables
• Column names checked before a query runs: a SELECT that names a column the cached schema doesn't have is not run; Claude gets a "did you mean" and the table's columns instead, and an unknown-name error from the database gets the same correction appended (how it decides)
• SSH tunnels: encrypted connections through bastion hosts, with a pinned host key
• Four engines: PostgreSQL, MySQL/MariaDB (including Azure), SQLite, and SQL Server (including Azure SQL with passwordless sign-in through the Azure CLI)
• Performance tools: connection pooling, schema caching, batches with transactions, and EXPLAIN plans with dialect-specific advice
• Runtime configuration: add, update and lock connections through MCP tools, without a restart, and never with write access the model granted itself

Installation

Requirements: Node.js >= 24.15 and the Claude Code CLI. Connecting to Azure SQL with authentication=azure-cli additionally needs the Azure CLI on PATH and a completed az login; nothing else does.

1. Build

git clone https://github.com/AraneaDev/argos.git
cd argos
npm install
npm run build

2. Configure databases

npm run setup

Interactive wizard for adding database connections, security settings, and SSH tunnels. It writes a config.ini, by convention at ~/.config/argos/config.ini, though any path works. You can also add databases at runtime with the sql_add_database tool.

3. Register with Claude Code

claude mcp add argos --scope user -- \
  node "$(pwd)/dist/cli.js" serve --config "$HOME/.config/argos/config.ini"

Scopes:

Scope	Flag	Where it lives	Use when
User	--scope user	~/.claude.json	You want Argos in every project (most common)
Project	--scope project	.mcp.json in the repo	You want to share it with your team via git
Local	(default)	Per-project, private	You're just trying it out

4. Install the pane

node dist/cli.js install-plugin --config "$HOME/.config/argos/config.ini"            # preview
node dist/cli.js install-plugin --config "$HOME/.config/argos/config.ini" --execute  # install

Use the same config.ini you registered the server with: the pane reads the history the server writes beside it. Start a new Claude Code session afterwards.

5. Verify

claude mcp list

You should see argos listed as connected. Its tools appear in Claude Code as mcp__argos__sql_query, mcp__argos__sql_get_schema, and so on, and /argos opens the pane.

Removing it

claude plugin uninstall argos
claude plugin marketplace remove argos
claude mcp remove argos --scope user

Quick start

Ask Claude about your data in plain words, and watch the queries land in the pane:

• "Show me the top 10 customers by revenue this quarter, including their growth rate compared to last quarter"
• "How many signups in the last 24 hours, and any error patterns?"
• "Analyze the performance of our product catalog queries and suggest optimizations"
• "Generate test data scenarios based on our current user demographics"

Claude reads the schema first, then queries; each result comes back to it as a short table, and in full to you in the pane.

The pane

Queries: every query Claude or you ran, newest first and kept across sessions, with the selected one's SQL and its full result. r reruns it read-only, p pins it, c copies the result as markdown, CSV or JSON, and s puts one of your own results into your next message to Claude.

Schema: each connection's tables and views, the open table's columns with their keys, and its relations in and out.

Editor: type SQL against any connection and run it. A write is refused with the reason, even on a connection that allows Claude to write.

Connections: each database with its engine, host, tunnel, access and schema age.

Every tab, key, setting and limit is in the pane guide.

CLI

Command	Description
argos serve	Start the Argos MCP server on stdio (this is what Claude Code invokes)
argos setup	Run the interactive configuration wizard
argos install-plugin	Install the Claude Code pane (preview; --execute to install)
argos connections	List the configured connections as JSON
argos schema <db> [--refresh]	Print a database's schema as JSON
argos query <db> --sql <sql>	Run a read-only query and record it in the history
argos history, argos result <id>	Page through the history and a saved result
argos pin, argos unpin <id>, argos pins	Manage pinned queries
argos help	Show usage (also what plain argos does)
argos version	Show the version

The pane runs the JSON commands for you; they are there for scripts too. argos is exposed as a bin entry, so npm link (or a global install) puts it on your PATH.

Configuration examples

Production PostgreSQL with SSH

[database.production]
type=postgresql
host=internal-db.company.local
port=5432
database=production_app
username=readonly_user
password=secure_random_password
ssl=true
select_only=true
timeout=15000

# SSH Tunnel Configuration
ssh_host=bastion.company.com
ssh_port=22
ssh_username=tunnel_user
ssh_private_key=/secure/path/ssh_key
# Required: without a pinned fingerprint the tunnel refuses to connect, rather
# than trusting whatever host key it is offered. Get it from the bastion with
#   ssh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub
ssh_host_fingerprint=SHA256:47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU

[security]
max_joins=5
max_subqueries=3
max_complexity_score=50

Azure SQL without a password

The Azure CLI's own sign-in is the credential, so no secret is written to config.ini at all.

[database.azure_sql]
type=mssql
host=your-server.database.windows.net
port=1433
database=your_database_name
authentication=azure-cli
select_only=true

# Only when the server's tenant is not the CLI's active context, which is the
# usual case for an account with access to several tenants. Must be the GUID.
# azure_tenant_id=00000000-0000-0000-0000-000000000000

Needs az login beforehand, and the signed-in identity mapped as a database user. Map a dedicated reader identity, or a group, with db_datareader only:

CREATE USER [argos-readers] FROM EXTERNAL PROVIDER;
ALTER ROLE db_datareader ADD MEMBER [argos-readers];

Do not let Argos sign in as the server's Entra admin: the admin is a member of db_owner in every user database and enters each one as dbo, so the only thing between the agent and a DELETE is Argos's filter. Argos checks this on connect and warns (see the database role check). Encryption and certificate verification are forced on for this mode, because an access token is a bearer credential and an unverified connection hands it to whoever answers.

A separate Azure identity for the agent

The Azure CLI keeps its sign-in in a profile directory, ~/.azure unless AZURE_CONFIG_DIR says otherwise. Sign the reader identity in to a profile of its own, and start Argos with that variable, so the agent never uses your own, possibly admin, login:

export AZURE_CONFIG_DIR="$HOME/.azure-claude-ro"
az login            # as the reader identity
claude mcp add argos --scope user -e AZURE_CONFIG_DIR="$HOME/.azure-claude-ro" -- \
  node "$(pwd)/dist/cli.js" serve --config "$HOME/.config/argos/config.ini"

Your own shell keeps ~/.azure and your own login. To give one database its own profile instead of the whole server, set azure_config_dir on it:

[database.azure_sql]
type=mssql
host=your-server.database.windows.net
database=your_database_name
authentication=azure-cli
azure_config_dir=~/.azure-claude-ro

Then check who Argos is from inside a session, with sql_query:

SELECT USER_NAME() AS db_user, IS_ROLEMEMBER('db_owner') AS is_owner,
       IS_ROLEMEMBER('db_datawriter') AS is_writer;

db_user should be the reader, and both flags 0. sql_test_connection runs the same check and says so.

See the SQL Server guide for the details, including unattended use.

Azure Database for PostgreSQL without a password

The same Azure CLI sign-in works for Azure Database for PostgreSQL. The Entra access token is the password, fetched fresh for every new connection because it is valid for 5 to 60 minutes.

[database.azure_pg]
type=postgresql
host=your-server.postgres.database.azure.com
port=5432
database=your_database_name
username=argos-readers
authentication=azure-cli
select_only=true
# azure_tenant_id=00000000-0000-0000-0000-000000000000

username is the Entra user or group as mapped in the database with pgaadauth_create_principal. TLS with certificate verification is forced, for the same reason as for Azure SQL. See the PostgreSQL guide.

Multi-Database Analytics Setup

[database.transactions]
type=postgresql
host=transactions-db.company.com
database=transactions
select_only=true

[database.users]
type=mysql
host=users-db.company.com
database=users
select_only=true

[database.analytics]
type=sqlite
file=./data/analytics.sqlite
select_only=false

[database.local_cache]
type=sqlite
file=./data/cache.sqlite
select_only=false
mcp_configurable=true

[extension]
max_rows=1000
query_timeout=30000

Safety model

1. Query validation: SQL injection prevention and syntax analysis
2. Complexity limits: resource-intensive queries are refused
3. SELECT-only mode: Argos refuses anything but a read. The filter is a second net: the database role is the boundary, so for a select_only database Argos asks the database once per connection whether its role can write, and warns in sql_test_connection, sql_list_databases and the pane when it can. Set require_readonly_role=true to refuse such a connection instead
4. Read-only pane: what you run from the pane opens read-only at the database (SQLite read-only mode, a read-only PostgreSQL or MySQL session) behind the SELECT-only check; SQL Server has no session-level equivalent and relies on the check. The pane guide says exactly what each engine guarantees
5. Connection encryption: SSL/TLS and SSH tunnel support
6. Audit logging: comprehensive security event tracking
7. Field redaction: automatic masking of sensitive data in query results

Field Redaction

Automatically mask, replace, or partially obscure sensitive fields (emails, phone numbers, SSNs, etc.) in query results before they reach Claude, the pane, or other clients. Redaction is configured per-database in config.ini:

[database.production]
type=postgresql
host=prod-db.company.com
database=app_db
username=readonly_user
password=secure_pass
select_only=true

# Field Redaction
redaction_enabled=true
redaction_rules=*email*:partial_mask,*phone*:full_mask,ssn:replace:[PROTECTED]
redaction_case_sensitive=false
redaction_log_access=true

Redaction types:

Type	Example Input	Example Output
partial_mask	john.doe@example.com	j******.e@*****.com
full_mask	555-123-4567	********** (capped at 10)
replace	123-45-6789	[PROTECTED]
custom	Regex-based	Custom pattern

Field patterns: exact match (email), wildcard (*email*), or regex (/^user_.+$/).

Full Redaction Guide

What this gives you towards compliance

Argos is not certified against any standard, and no library can be. Compliance is a property of your deployment. What it provides is the controls and the evidence that such a regime asks for:

• Read-only enforcement that cannot be relaxed from a session
• Field redaction, so protected columns never reach the model
• An audit record per query: timestamp, database, statement hash, duration, outcome, with no values and no SQL
• Secrets scrubbed from logs and error messages
• Owner-only file modes on the log, the audit records, the configuration and the pane's history

The pane's history (.argos/ beside your config.ini) holds query text and redacted results for up to 30 days, so it is git-ignored and owner-only.

Runtime database management

Argos supports runtime database management through dedicated MCP tools. This allows you to add, update, and remove database connections without restarting the server.

Tool	Description	Requirements
sql_add_database	Add new database connections at runtime via MCP	None
sql_update_database	Update existing database settings via MCP	mcp_configurable=true on the target database
sql_remove_database	Remove database connections via MCP	mcp_configurable=true on the target database
sql_get_config	View database configuration (passwords are automatically redacted)	None
sql_set_mcp_configurable	Lock a database from MCP changes	One-way operation: can only lock (false), unlocking requires manual config edit

• Set mcp_configurable=true in your database config to allow MCP-driven updates and removal.
• The sql_set_mcp_configurable tool is a one-way lock: once set to false, the database can no longer be modified or removed via MCP. Unlocking requires a manual edit to the configuration file.
• The sql_get_config tool always redacts passwords and other sensitive fields before returning configuration data.
• Databases added at runtime via sql_add_database have mcp_configurable=true by default, and are always select_only=true. Granting write access requires editing config.ini by hand, so the model cannot grant it to itself.

Performance

Query time is your database's, not Argos's. It adds validation and formatting around a normal client connection. sql_get_metrics reports the latency it actually observed (min, max, avg, p95), and sql_analyze_performance returns the execution plan with dialect-specific advice when something is slow.

• Connection pooling: reuse database connections efficiently
• Schema caching: captured once per database, checked cheaply for changes at most once a minute
• Result streaming: large result sets never fully materialise in memory
• Batch operations: several queries in one call, optionally in one transaction

Architecture

graph TB
 Claude[Claude Code] --> MCP[MCP Protocol]
 MCP --> Security[Security Layer]
 Security --> Connection[Connection Manager]
 Connection --> Adapters[Database Adapters]

 Adapters --> PostgreSQL[(PostgreSQL)]
 Adapters --> MySQL[(MySQL)]
 Adapters --> SQLite[(SQLite)]
 Adapters --> MSSQL[(SQL Server)]

 Security --> SSH[SSH Tunneling]
 SSH --> Bastion[Bastion Host]
 Bastion --> RemoteDB[(Remote Database)]

 Connection --> History[(.argos history)]
 Pane[Claude Code pane] --> CLI[argos CLI, read-only]
 CLI --> Security
 CLI --> History

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The pane cannot reach the MCP server over stdio, so it runs the argos CLI, which reads the same config.ini and history and goes through the same security, redaction and audit layers.

Documentation

Getting started

• 5-Minute Quick Start: get running fast
• Installation Guide: detailed setup instructions
• First Database Tutorial: connect your first database
• Claude Integration: register with Claude Code
• The Claude Code pane: every tab, key and setting

Architecture and design

• System Architecture: how it all works together
• Security Architecture: defense-in-depth security model
• Database Layer: adapter pattern implementation

API reference

• MCP Tools Reference: complete tool documentation
• TypeScript API: developer API reference
• Configuration Reference: all configuration options

Advanced guides

• Multi-Database Setup: managing multiple databases
• SSH Tunneling: secure remote access
• Security Hardening: production security guide
• Performance Tuning: optimization strategies

Browse all documentation

Development

git clone https://github.com/AraneaDev/argos.git
cd argos
npm install
npm run dev
npm test           # the server and CLI (jest)
npm run test:mod   # the Claude Code pane (vitest)
npm run validate   # everything CI runs

The README and pane guide images come from node tools/capture/shoot.mjs, which drives an isolated Claude Code session on demo data; see tools/capture/.

Full Development Guide

Layers

The source is layered, and a lower layer may never depend on a higher one:

layer	directory	may depend on
types	src/types	nothing in src
utils	src/utils	types
adapters	src/database	types, utils
domain	src/classes, src/schema, src/pane	types, utils, adapters
mcp-tools	src/tools	everything below
cli	src/cli, src/setup	everything below, and nothing depends on it

Nothing in src imports from tests or examples, and the pane (plugin/) imports nothing from src: it talks to the CLI's JSON.

These rules are not enforced by CI. They are a design constraint, checked by hand or by whatever analysis tool you point at the checkout, so read the table before adding an import that reaches upward. A cycle between layers is the signal that something belongs in a lower one.

Migrating from Argos-MCP

The project was renamed from Argos-MCP to Argos. If you set it up before the rename:

• Claude Code registration: re-register under the new name so the tools appear as mcp__argos__*:

  claude mcp remove argos-mcp   # whatever name you registered it under
  claude mcp add argos --scope user -- \
    node /abs/path/to/argos/dist/cli.js serve --config /abs/path/config.ini

• Commands: argos-mcp is now argos serve, and argos-setup is now argos setup. The old names still work for one release and print a deprecation notice to stderr.

• Audit logs are now written to ~/.argos/audit/. Earlier logs stay in ~/.argos-mcp/audit/; move them over if you want one trail.

• Server log is now argos.log (was argos-mcp.log).

• Repository: AraneaDev/Argos-MCP is now AraneaDev/argos; GitHub redirects the old URL, but update your remote with git remote set-url origin https://github.com/AraneaDev/argos.git.

Further reading

• How to give Claude safe access to your SQL database

License

Released under the MIT License, free for any use, commercial included, with no warranty.

Acknowledgments

• Anthropic: for Claude and the MCP protocol
• Database driver maintainers: for reliable connectivity libraries
• Built with TypeScript, Node.js, Jest and Vitest

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Built by Tim Schipper and released as open source under Aranea Development.