J Link MCP

Debug embedded firmware on real hardware: J-Link probes, Cortex-M faults, RTT logs, GDB.

Quick Install

Automated & IDE Setup

Copy the AI prompt to install this server into Claude Code, Cursor, or another agent — or use 1-click editor setup below.

Add to Cursor Add to VS Code

Not yet automatically verified

We haven't yet run this listing's install command through our automated sandbox check. This isn't a red flag — we're steadily working through the catalog.

Manual Client & Custom JSON ConfigExpand JSON ▾

Client Config & Setup

Choose your client or environment

Target File:~/Library/Application Support/Claude/claude_desktop_config.json

claude_desktop_config.json

{
  "mcpServers": {
    "j-link-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "jlink-mcp"
      ]
    }
  }
}

💡 Paste the JSON block into your client's configuration file under mcpServers, then restart the application.

Documentation Overview

jlink-mcp

Give AI hands to touch silicon.
An MCP server that lets LLMs debug embedded devices through SEGGER J-Link probes.

See it work

A terminal session: the MCP server finds the probe, flashes firmware, opens a debug session, streams RTT logs, injects a fault, and decodes the resulting HardFault — naming the faulting instruction.

Real MCP tool calls against a real nRF52840-DK. Reproduce it yourself: npm run demo

Your firmware just crashed. One tool call:

Code

> diagnose_crash

## Crash Diagnosis

### CPU State
Core: PC=0x000000B8 SP=0x2003FFA8 R0=0x0000000A R1=0x000007FF R2=0x00000001 ...
Status: XPSR=0x21000003 CONTROL=0x00000000 PRIMASK=0x00000000 ...
Stack: MSP=0x2003FFA8 PSP=0x00000000

⚠ CPU is in exception handler (IPSR=0x00000003)

### Fault Registers
CFSR=0x01000000 HFSR=0x40000000 DFSR=0x00000000 MMFAR=0xe000edf8 BFAR=0xe000edf8

### Decoded Faults
## UsageFault (UFSR):
  - UNALIGNED: Unaligned memory access
## HardFault (HFSR):
  - FORCED: Forced HardFault (escalated from configurable fault)

### Exception Stack Frame
  R0    = 0x0000000A     R1  = 0x000007FF
  R12   = 0x00000000     LR  = 0x000001F5
  PC    = 0x00000254     xPSR = 0x21000000

→ Faulting instruction at PC=0x00000254

### Recent Errors/Warnings from RTT
  [WRN] sensor_drv: sample out of range, clamping seq=2

Fault decoded, exception frame unwound, faulting instruction named, and the device's own log correlated — from one call, without a human reading a datasheet to find out what bit 24 of CFSR means.

And it knows what the silicon is

Point it at your target's CMSIS-SVD file and peripheral registers stop being hex:

Code

> read_peripheral FICR

FICR @ 0x10000000
INFO.PART @ 0x10000100 = 0x00052840  (read-only)
  [31:0]    PART             0x52840 → N52840
INFO.RAM @ 0x1000010C = 0x00000100  (read-only)
  [31:0]    RAM              0x100 → K256
INFO.FLASH @ 0x10000110 = 0x00000400  (read-only)
  [31:0]    FLASH            0x400 → K1024

0x400 means 1024 KB of flash — but only if you know that, and an LLM guessing at bit layouts is exactly the failure this avoids. The addresses come from the vendor's own description, and the meanings from its enumerations.

Both transcripts are verbatim output from an nRF52840-DK in this project's hardware test suite.

What is this?

jlink-mcp connects AI assistants (Claude, Copilot, etc.) to your embedded hardware via SEGGER J-Link debug probes using the Model Context Protocol.

Instead of manually typing J-Link commands, your AI assistant can:

Read registers and memory to understand device state
Flash firmware and reset devices
Stream RTT logs and search them by level/module/regex
Diagnose crashes by auto-decoding ARM Cortex-M fault registers
Control execution — halt, step, resume, breakpoints
Start GDB servers for full debugging sessions

Also supports OpenOCD (ST-Link, CMSIS-DAP, FTDI) and Black Magic Probe backends.

Installing

You need the SEGGER J-Link software — that is what this server drives — a probe connected to an ARM Cortex-M target, and Node 18+. For the other backends, OpenOCD or arm-none-eabi-gdb instead.

Claude Code — from the plugin marketplace. This brings the embedded-debugging skill along with the server, which is what stops an assistant guessing at your hardware:

Code

/plugin marketplace add Klievan/jlink-mcp
/plugin install jlink-mcp

Any other agent — point it at this repository and ask it to set itself up:

Install the MCP server at https://github.com/Klievan/jlink-mcp and configure it for my board.

It will find what it needs here. If you would rather do it by hand, the server is on npm and needs no build step: npx -y jlink-mcp, with JLINK_DEVICE set to your target. mcp-config.json is a config you can paste.

VS Code — install the extension. It registers the server for Copilot Chat, Claude, and any MCP-aware client, so there is nothing to configure.

Then check it

Ask for check_setup. One call, and it says what is missing and what to do:

Code

Not ready to debug yet.

OK    probe software — J-Link software found at /Applications/SEGGER/JLink
BLOCK probe — none detected (Connecting to J-Link via USB...FAILED). Check the USB cable.
BLOCK target device — not set. Find the exact name with search_devices, then set_device.
note  SVD — not loaded, so peripheral reads stay raw hex. Set SVD_PATH to a CMSIS-SVD file.

You do not need your device's exact part number up front. search_devices searches all 9800 that J-Link supports, by part number, manufacturer, or core.

Tools (47)

Workflow Tools (start here)

Tool	Description
`start_debug_session`	One-call setup. Starts GDB server + connects RTT + returns boot log.
`snapshot`	Captures full device state: registers, fault status, stack dump, RTT output.
`diagnose_crash`	Auto-reads and decodes ARM Cortex-M fault registers (CFSR, HFSR, MMFAR, BFAR) with exception stack frame.

Device Setup

Tool	Description
`list_devices`	Scan for connected probes and show the configured target
`set_device`	Change the target device at runtime — no restart needed
`get_config`	Current probe, target device, and GDB server state

Device Control

Tool	Description
`device_info`	Probe type, target CPU, compact register summary
`halt`	Halt CPU
`resume`	Resume CPU
`reset`	Reset device. `halt` stops it at the reset vector; `strategy` picks a J-Link reset type, or omit it and let J-Link choose
`step`	Single-step one instruction

Peripherals (CMSIS-SVD)

Set jlinkMcp.svdPath to your target's SVD — the same file Cortex-Debug takes as svdFile. Vendors publish one per part.

Tool	Description
`list_peripherals`	Every peripheral and base address on the chip
`read_peripheral`	Read a peripheral's registers and decode each one's bit fields by name
`decode_register`	Decode one register — read from the device, or interpret a value you already have

Memory & Registers

Tool	Description
`read_memory`	Read memory at address (clean hex dump output)
`write_memory`	Write 32-bit value to address
`read_registers`	All CPU registers in compact format
`read_register`	Read specific register (PC, SP, R0-R12, etc.)

Flash

Tool	Description
`flash`	Flash .hex/.bin/.elf firmware to device
`erase`	Erase entire flash

Breakpoints

Tool	Description
`set_breakpoint`	Set hardware breakpoint at address
`clear_breakpoints`	Clear all breakpoints

GDB Server

Tool	Description
`gdb_server_start`	Start probe's GDB server
`gdb_server_stop`	Stop GDB server + disconnect RTT
`gdb_server_status`	GDB server, RTT, and proxy status

Source-Level Debugging

Attach a real GDB client for symbol-aware work — backtraces, variable inspection, and stepping by source line rather than by instruction.

Read the full README →View source on GitHub →

Related MCP Servers

View all in Developer Tools View all alternatives

Reviews

No reviews yet — be the first to share how this listing worked for you.

Frequently Asked Questions about J Link MCP

Add the following block to your claude_desktop_config.json under mcpServers: "mcpServers": { "j-link-mcp": { "command": "npx", "args": ["-y", "J-Link MCP"] } }

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Technical Specs & Signals

CategoryDeveloper Tools

40Quality signal: Fair · 40/100How this signal is calculated ▾

Server availabilityNot measured

Not scored for repo-hosted servers — we can't reach the running server, only its GitHub page. Hosted MCP endpoints are health-checked live.

Verified ownership10/20

Documentation & tools16/30

Adoption & activity4/15

Community engagement0/10

A guidance signal from public completeness & health data — not a user rating. New listings start lower and rise as they add docs, get verified, and grow adoption. Signals we can't observe for a listing are skipped, not counted against it.

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 2d ago via OSV.dev · jlink-mcp (npm)

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More in 💻 Developer Tools →Best MCP servers for Developers →Alternatives to J Link MCP →Install in Claude Desktop Install in Cursor Install in VS Code

J Link MCP

Debug embedded firmware on real hardware: J-Link probes, Cortex-M faults, RTT logs, GDB.

Quick Install

Automated & IDE Setup

Copy the AI prompt to install this server into Claude Code, Cursor, or another agent — or use 1-click editor setup below.

Add to Cursor Add to VS Code

Not yet automatically verified

We haven't yet run this listing's install command through our automated sandbox check. This isn't a red flag — we're steadily working through the catalog.

Manual Client & Custom JSON ConfigExpand JSON ▾

Client Config & Setup

Choose your client or environment

Target File:~/Library/Application Support/Claude/claude_desktop_config.json

claude_desktop_config.json

{
  "mcpServers": {
    "j-link-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "jlink-mcp"
      ]
    }
  }
}

💡 Paste the JSON block into your client's configuration file under mcpServers, then restart the application.

Documentation Overview

jlink-mcp

Give AI hands to touch silicon.
An MCP server that lets LLMs debug embedded devices through SEGGER J-Link probes.

See it work

Real MCP tool calls against a real nRF52840-DK. Reproduce it yourself: npm run demo

Your firmware just crashed. One tool call:

Code

> diagnose_crash

## Crash Diagnosis

### CPU State
Core: PC=0x000000B8 SP=0x2003FFA8 R0=0x0000000A R1=0x000007FF R2=0x00000001 ...
Status: XPSR=0x21000003 CONTROL=0x00000000 PRIMASK=0x00000000 ...
Stack: MSP=0x2003FFA8 PSP=0x00000000

⚠ CPU is in exception handler (IPSR=0x00000003)

### Fault Registers
CFSR=0x01000000 HFSR=0x40000000 DFSR=0x00000000 MMFAR=0xe000edf8 BFAR=0xe000edf8

### Decoded Faults
## UsageFault (UFSR):
  - UNALIGNED: Unaligned memory access
## HardFault (HFSR):
  - FORCED: Forced HardFault (escalated from configurable fault)

### Exception Stack Frame
  R0    = 0x0000000A     R1  = 0x000007FF
  R12   = 0x00000000     LR  = 0x000001F5
  PC    = 0x00000254     xPSR = 0x21000000

→ Faulting instruction at PC=0x00000254

### Recent Errors/Warnings from RTT
  [WRN] sensor_drv: sample out of range, clamping seq=2

Fault decoded, exception frame unwound, faulting instruction named, and the device's own log correlated — from one call, without a human reading a datasheet to find out what bit 24 of CFSR means.

And it knows what the silicon is

Point it at your target's CMSIS-SVD file and peripheral registers stop being hex:

Code

> read_peripheral FICR

FICR @ 0x10000000
INFO.PART @ 0x10000100 = 0x00052840  (read-only)
  [31:0]    PART             0x52840 → N52840
INFO.RAM @ 0x1000010C = 0x00000100  (read-only)
  [31:0]    RAM              0x100 → K256
INFO.FLASH @ 0x10000110 = 0x00000400  (read-only)
  [31:0]    FLASH            0x400 → K1024

Both transcripts are verbatim output from an nRF52840-DK in this project's hardware test suite.

What is this?

jlink-mcp connects AI assistants (Claude, Copilot, etc.) to your embedded hardware via SEGGER J-Link debug probes using the Model Context Protocol.

Instead of manually typing J-Link commands, your AI assistant can:

Read registers and memory to understand device state
Flash firmware and reset devices
Stream RTT logs and search them by level/module/regex
Diagnose crashes by auto-decoding ARM Cortex-M fault registers
Control execution — halt, step, resume, breakpoints
Start GDB servers for full debugging sessions

Also supports OpenOCD (ST-Link, CMSIS-DAP, FTDI) and Black Magic Probe backends.

Installing

You need the SEGGER J-Link software — that is what this server drives — a probe connected to an ARM Cortex-M target, and Node 18+. For the other backends, OpenOCD or arm-none-eabi-gdb instead.

Claude Code — from the plugin marketplace. This brings the embedded-debugging skill along with the server, which is what stops an assistant guessing at your hardware:

Code

/plugin marketplace add Klievan/jlink-mcp
/plugin install jlink-mcp

Any other agent — point it at this repository and ask it to set itself up:

Install the MCP server at https://github.com/Klievan/jlink-mcp and configure it for my board.

VS Code — install the extension. It registers the server for Copilot Chat, Claude, and any MCP-aware client, so there is nothing to configure.

Then check it

Ask for check_setup. One call, and it says what is missing and what to do:

Code

Not ready to debug yet.

OK    probe software — J-Link software found at /Applications/SEGGER/JLink
BLOCK probe — none detected (Connecting to J-Link via USB...FAILED). Check the USB cable.
BLOCK target device — not set. Find the exact name with search_devices, then set_device.
note  SVD — not loaded, so peripheral reads stay raw hex. Set SVD_PATH to a CMSIS-SVD file.

You do not need your device's exact part number up front. search_devices searches all 9800 that J-Link supports, by part number, manufacturer, or core.

Tools (47)

Workflow Tools (start here)

Tool	Description
`start_debug_session`	One-call setup. Starts GDB server + connects RTT + returns boot log.
`snapshot`	Captures full device state: registers, fault status, stack dump, RTT output.
`diagnose_crash`	Auto-reads and decodes ARM Cortex-M fault registers (CFSR, HFSR, MMFAR, BFAR) with exception stack frame.

Device Setup

Tool	Description
`list_devices`	Scan for connected probes and show the configured target
`set_device`	Change the target device at runtime — no restart needed
`get_config`	Current probe, target device, and GDB server state

Device Control

Tool	Description
`device_info`	Probe type, target CPU, compact register summary
`halt`	Halt CPU
`resume`	Resume CPU
`reset`	Reset device. `halt` stops it at the reset vector; `strategy` picks a J-Link reset type, or omit it and let J-Link choose
`step`	Single-step one instruction

Peripherals (CMSIS-SVD)

Set jlinkMcp.svdPath to your target's SVD — the same file Cortex-Debug takes as svdFile. Vendors publish one per part.

Tool	Description
`list_peripherals`	Every peripheral and base address on the chip
`read_peripheral`	Read a peripheral's registers and decode each one's bit fields by name
`decode_register`	Decode one register — read from the device, or interpret a value you already have

Memory & Registers

Tool	Description
`read_memory`	Read memory at address (clean hex dump output)
`write_memory`	Write 32-bit value to address
`read_registers`	All CPU registers in compact format
`read_register`	Read specific register (PC, SP, R0-R12, etc.)

Flash

Tool	Description
`flash`	Flash .hex/.bin/.elf firmware to device
`erase`	Erase entire flash

Breakpoints

Tool	Description
`set_breakpoint`	Set hardware breakpoint at address
`clear_breakpoints`	Clear all breakpoints

GDB Server

Tool	Description
`gdb_server_start`	Start probe's GDB server
`gdb_server_stop`	Stop GDB server + disconnect RTT
`gdb_server_status`	GDB server, RTT, and proxy status

Source-Level Debugging

Attach a real GDB client for symbol-aware work — backtraces, variable inspection, and stepping by source line rather than by instruction.

Read the full README →View source on GitHub →

Related MCP Servers

View all in Developer Tools View all alternatives

Reviews

No reviews yet — be the first to share how this listing worked for you.

Frequently Asked Questions about J Link MCP

Add the following block to your claude_desktop_config.json under mcpServers: "mcpServers": { "j-link-mcp": { "command": "npx", "args": ["-y", "J-Link MCP"] } }

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Showcase your server listing on GitHub or your project documentation. Embed this dynamic SVG badge to highlight official listing status and live engagement.

Badge Style:

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Markdown (GitHub README)

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<a href="https://allmcps.com/mcp/j-link-mcp"><img src="https://allmcps.com/api/badge/j-link-mcp?style=directory" alt="J Link MCP on AllMCPs" /></a>

Technical Specs & Signals

CategoryDeveloper Tools

40Quality signal: Fair · 40/100How this signal is calculated ▾

Server availabilityNot measured

Not scored for repo-hosted servers — we can't reach the running server, only its GitHub page. Hosted MCP endpoints are health-checked live.

Verified ownership10/20

Documentation & tools16/30

Adoption & activity4/15

Community engagement0/10

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 2d ago via OSV.dev · jlink-mcp (npm)

★ Featured

Moxie Docs MCP

MCP & Agent Skills for Automated Documentation, and codebase conventions + context

Explore Server →

Own this project?

Free dofollow backlink: add your website and place the AllMCPs badge on it — no claim needed. We detect it automatically and keep it verified as long as the badge stays live.

Claim & get free dofollow

Share & Embed

Add our SVG badge (dark/light directory styles) or embeddable widget to your site.

Explore more

More in 💻 Developer Tools →Best MCP servers for Developers →Alternatives to J Link MCP →Install in Claude Desktop Install in Cursor Install in VS Code