MCP J-Link Server

by gghammer

Overview Schema Source Related Servers Discussions Admin

Python

rtt_write

Write data to RTT down buffer for host-to-device communication in embedded debugging with SEGGER J-Link probes.

Instructions

寫入資料到 RTT 下行緩衝區（主機→裝置方向）。

Args: text: 要傳送的文字內容 buffer_index: RTT 下行緩衝區索引，預設 0

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "text": "<text>"
    },
    "name": "rtt_write"
  }
}

Input Schema

Name	Required	Description	Default
`text`	Yes
`buffer_index`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Mar 21, 2026

TDQS

B3.2/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden. It states this is a write operation but doesn't disclose important behavioral aspects: whether this is synchronous/asynchronous, error conditions, buffer overflow behavior, or what happens if RTT isn't active. The description is minimal beyond the basic operation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Extremely concise with zero wasted words. The description is front-loaded with the core purpose, followed by clear parameter explanations. Every sentence serves a distinct purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the basic operation and parameters adequately. However, for a write operation with no annotations and complex sibling tools, it should ideally mention prerequisites (RTT must be started) and behavioral expectations. The existence of an output schema helps but doesn't fully compensate for the lack of operational context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage, the description compensates well by explaining both parameters: 'text' as the content to send and 'buffer_index' as the RTT downlink buffer index with default value 0. This adds meaningful context beyond the bare schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('寫入資料' - write data) and target ('RTT 下行緩衝區' - RTT downlink buffer) with direction specified ('主機→裝置方向' - host→device direction). It distinguishes from sibling rtt_read but doesn't explicitly contrast with other RTT tools like rtt_start/stop.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives. While it's clear this is for writing to RTT buffers, there's no mention of prerequisites (e.g., whether RTT must be started first using rtt_start) or when to choose this over other communication methods.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.