Quickstart

npm (recommended)

Install nothing — let your MCP client launch the server with npx:

codex mcp add cmsis-dap -- npx -y cmsis-dap-mcp

The npm package cmsis-dap-mcp downloads the correct platform binary automatically on first launch and caches it afterwards.

To pin a version:

codex mcp add cmsis-dap -- npx -y cmsis-dap-mcp@0.5.0

Native binary

Download the binary for your platform from the GitHub Releases page, then point the client at it:

codex mcp add cmsis-dap -- /path/to/cmsis-dap-mcp --log-level warn

This is the standard way to run an unpublished or locally built server, or when you need an exact, offline-pinned binary.

Configuration styles

MCP clients can start a stdio server in three equivalent ways. The npx form is the standard for published packages; the local-binary form is equivalent and used for local builds.

Style	Example	Best for
`npx` package	`command = "npx", args = ["-y", "cmsis-dap-mcp"]`	Published releases; updates with npm
Local binary	`command = "/path/to/cmsis-dap-mcp"`	Local builds, offline, exact version
Remote URL	`url = "https://..."`	Streamable-HTTP servers (not supported by this project)

All three clients covered on the AI client configuration page accept both the npx form and a local binary path; the server behaves identically either way.

First session

The server can be started with zero arguments — it enters a to-be-configured state where all read/write tools work and destructive tools stay gated until enabled (see step 7).

list_probes to find your probe id.
connect with {"protocol": "swd", "speed_khz": 1000}.
read_memory / write_memory for raw access.
halt, then read_core_register (e.g. pc, sp, lr, r0).
resume when done.
load_svd with your own SVD path for named peripheral access.
program_flash / erase_flash require destructive mode: start the server with --allow-destructive, or call update_config {"allow_destructive": true} at runtime (no restart needed).
For a chip not built into probe-rs, call define_chip with a Keil FLM file before connect (see Tools).

Example (verified output on a CMSIS-DAP probe + Cortex-M0+ board):

list_probes -> {"probes": [{"id": "0123456789AB", "product": "CMSIS-DAP", ...}]}
connect {protocol: swd, speed_khz: 1000}
  -> {"target": {"core_type": "Armv6m", "core_count": 1, "ap_count": 1, "cpu_id": ..., "dp_id": ...}}
read_memory {address: 0x20000000, width: u32, count: 4}
  -> {"values": [64000000, 1, 3, 0]}
halt -> {"halted": true}
read_core_register {name: pc} -> {"value": 134228884}
resume -> {"running": true}

CLI quick start

The standalone cmsis-dap-cli shares the same engine and auto-connects with the global options (--probe-id, --target, --target-yaml, …):

cmsis-dap-cli --probe-id 0123456789AB --target STM32F030C8 connect
cmsis-dap-cli --probe-id 0123456789AB --target STM32F030C8 read --address 0x20000000 --width u32 --count 4
cmsis-dap-cli --probe-id 0123456789AB --target STM32F030C8 --elf fw.axf watch counter --interval-ms 200 --count 0
cmsis-dap-cli --probe-id 0123456789AB --target STM32F030C8 --elf fw.axf rtt monitor --count 0
cmsis-dap-cli --probe-id 0123456789AB --target STM32F030C8 --elf fw.axf evr monitor --count 0

Use repl to keep one session open (halt/read/resume across lines, or run the watch/RTT/Event Recorder monitors after reset run). See the CLI reference for the full command set.

Logs go to stderr only; the MCP protocol runs over stdout.