Pixinsight Connector MCP Server

PixInsight Connector

An MCP connector that lets any AI agent operate PixInsight: about 80 PixInsight operations as tools, for chat sessions and the skills that guide them. New here? Start with the Quick start.

Community project, not affiliated with or endorsed by Pleiades Astrophoto. PixInsight® is a registered trademark of Pleiades Astrophoto S.L.

The principle: a toolbox, not a pipeline

The connector knows how to operate PixInsight, never what makes a good picture. No pipeline, no ordering, no recommended values, no verdicts: every tool takes the values that shape the image as inputs, and every measurement returns numbers. The knowledge (which tools, in what order, with which values, what counts as good enough) lives in skills: markdown in your own repositories, public or private.

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flowchart TB
    classDef know fill:#0f766e,stroke:#115e59,color:#f0fdfa,stroke-width:1px,rx:12,ry:12
    classDef harness fill:#475569,stroke:#334155,color:#f8fafc,stroke-width:1px,rx:12,ry:12
    classDef tool fill:#1e293b,stroke:#64748b,color:#f8fafc,stroke-width:1px,rx:12,ry:12
    classDef app fill:#e2e8f0,stroke:#94a3b8,color:#0f172a,stroke-width:1px
    You(["You, in a chat session"]):::know
    Skills("<b>The knowledge · yours</b><br/>your skills: order, values, quality gates<br/>kept in your own repositories"):::know
    Harness("<b>Any MCP agent harness</b><br/>Claude Code · Codex · Cursor · Gemini CLI · …"):::harness
    Tools("<b>The toolbox · this connector</b><br/>~80 PixInsight operations as MCP tools<br/>measurements return numbers, never verdicts"):::tool
    Bridge("<b>File bridge + watcher script</b><br/>starts PixInsight on the first call"):::tool
    PI(["PixInsight 1.9.5+"]):::app
    You --> Harness
    Skills -. guides .-> Harness
    Harness -- MCP tool calls --> Tools
    Tools --> Bridge
    Bridge <--> PI
    linkStyle default stroke:#8b949e,stroke-width:1.5px

Install

Needs Node 22+ and PixInsight 1.9.5+. The same three steps work whether you or your agent runs them.

1. Install the connector from npm:

npm install -g pixinsight-connector

2. Register it with your agent harness as the MCP server pixinsight. Claude Code:

claude mcp add -s user pixinsight -- pixinsight-connector

Any harness configured with an mcpServers JSON file (Cursor, Windsurf, Gemini CLI, Claude Desktop, Cline, Kiro):

{ "mcpServers": { "pixinsight": { "command": "pixinsight-connector" } } }

Codex, OpenCode, VS Code and Zed use other shapes; each one, and where its file lives: docs/setup.md.

3. Check the machine:

pixinsight-connector doctor

PixInsight and its watcher script start on the first tool call; there is nothing else to launch. Upgrade with npm install -g pixinsight-connector@latest. Without installing, register npx -y pixinsight-connector as the command instead (npx fetches it from npm, so the first start needs the network). From pixinsight-mcp 1.x: point your pixinsight entry at pixinsight-connector (not a second server) and npm uninstall -g pixinsight-mcp.

Where files go

The tools work in a target folder: the one set_workspace names, else PIXINSIGHT_CONNECTOR_WORKSPACE, else the folder the harness started in. The connector writes only <target>/agentic/ (scratch, the bridge, call logs) and <target>/output/, never your home folder. Details and every environment variable: docs/setup.md.

Tools, packs and skills

• Tools: 78, grouped as images, processes, channels, tone, detail, masks, stars, narrowband, astrometry, measurement, preview, PJSR execution, introspection and session. Full list: docs/tools.md.
• Skills hold the technique. Companion skills (environment preflight, dataset intake, a basic LRGB flow): pixinsight-connector-skills. Have one that works? Add it to COMMUNITY.md.
• Packs are ES modules that add or replace tools at startup, listed in PIXINSIGHT_CONNECTOR_PACKS. A pack is arbitrary code running with your privileges; only packs you configure load. See CONTRIBUTING.md.
• Models: any with vision and reliable tool calling. Start with a Sonnet-class model (Claude Sonnet 5, GPT-6 Sol, Gemini 3.8 Flash), then try cheaper ones (GPT-6 Luna, GLM-5.3-Flash, DeepSeek V4.1 Flash): prices and the list are in docs/setup.md.

Contributing

A PixInsight capability with no tool yet is one module in src/tools/, no registry: CONTRIBUTING.md. Humans and agents are both welcome; npm test needs no PixInsight.

Cross-platform

macOS, Windows and Linux are all first-class, for running this connector and for developing it. A change that works on one OS and breaks another is a bug, not a limitation.

• No shell pipelines. No ps, grep, awk, wc, df or && in src/ or in npm scripts. OS-specific behaviour goes behind src/platform.mjs (paths) or src/process-probe.mjs (process inspection), one implementation per OS.
• No POSIX path literals. Use path.join. Use forward slashes only when handing a path to PixInsight, which accepts them everywhere.
• CI runs the full suite on Linux, macOS and Windows. Green on one is not green.
• Degrade, never fail. If an OS cannot supply something optional — a memory reading, a process start time — carry on without it. Never report it as a crash.
• Overrides always win: PIXINSIGHT_BIN for the executable, PIXINSIGHT_DIR for the install root.

Tests need no PixInsight and no astronomy software, so you can develop on any of the three.

Troubleshooting

Run pixinsight-connector doctor first. Common symptoms and fixes: docs/troubleshooting.md.

Credit and license

This project began as aescaffre/pixinsight-mcp by Alain Escaffre; parts of the original file bridge and watcher script remain. MIT licensed: see LICENSE.