mcp-ros2-logs

An MCP server that gives AI agents the ability to analyze ROS2 log files across multiple nodes. It solves the core pain point of ROS2's fragmented logging — where each node writes to its own separate file — by merging them into a unified timeline and exposing smart query tools.

No ROS2 installation required. It just reads log files from disk.

Install

pipx install mcp-ros2-logs

Or with pip (in a virtual environment):

pip install mcp-ros2-logs

Or from source:

git clone https://github.com/spanchal001/mcp-ros2-logs.git
cd mcp-ros2-logs
pdm install

Setup

Claude Code

claude mcp add --scope user ros2-logs -- mcp-ros2-logs

This makes the server available in all Claude Code sessions. For project-scoped setup (current directory only), omit --scope user.

To set a custom log directory (and optionally a default result limit):

claude mcp add --scope user ros2-logs -e MCP_ROS2_LOGS_DIR=/path/to/logs -e MCP_ROS2_LOGS_MAX_RESULTS=50 -- mcp-ros2-logs

Claude Desktop

Add to ~/.config/Claude/claude_desktop_config.json (Linux) or ~/Library/Application Support/Claude/claude_desktop_config.json (macOS):

{
  "mcpServers": {
    "ros2-logs": {
      "command": "mcp-ros2-logs",
      "env": {
        "MCP_ROS2_LOGS_DIR": "/path/to/your/ros2/logs",
        "MCP_ROS2_LOGS_MAX_RESULTS": "100"
      }
    }
  }
}

VS Code (GitHub Copilot)

Add to .vscode/mcp.json in your workspace:

{
  "servers": {
    "ros2-logs": {
      "command": "mcp-ros2-logs",
      "env": {
        "MCP_ROS2_LOGS_DIR": "/path/to/your/ros2/logs",
        "MCP_ROS2_LOGS_MAX_RESULTS": "100"
      }
    }
  }
}

Then use Copilot in agent mode (@workspace) to query your logs.

Cursor

Open Settings > MCP Servers > Add Server and configure:

{
  "ros2-logs": {
    "command": "mcp-ros2-logs",
    "env": {
      "MCP_ROS2_LOGS_DIR": "/path/to/your/ros2/logs",
      "MCP_ROS2_LOGS_MAX_RESULTS": "100"
    }
  }
}

Tools

list_runs

Discover available log runs in the log directory.

"list my ROS2 log runs"
"list runs in /tmp/robot_logs"

load_run

Parse all log files in a run into a merged, sorted timeline.

"load the latest run"
"load bad_run from /tmp/robot_logs"

query_logs

Search and filter the merged timeline. Supports severity, node, time range, text, and context window filters.

"show me all errors and fatals"
"find messages containing 'timeout' from sensor_driver"
"show errors with 5 messages of context around each match"
"show warnings in the last 30 seconds of the run"

get_node_summary

Detailed analysis of a specific node: uptime, severity counts, recurring message patterns, unique errors, stack traces, and message rate.

"summarize the sensor_driver node"
"what errors did motion_planner have?"

get_timeline

Condensed narrative of a run. Groups consecutive messages, highlights severity transitions (INFO -> ERROR), and flags gaps where nodes went silent.

"show me a timeline of the run"
"what's the timeline for the last 10 seconds?"

compare_runs

Diff two runs to find what changed. Shows new/missing nodes, severity distribution changes, novel error messages, first divergence point, and timing differences.

"compare good_run vs bad_run"
"what's different between yesterday's run and today's?"

detect_anomalies

Statistically flags unusual patterns using the first portion of a run as a baseline. Detects rate spikes, new error patterns, severity escalations, silence gaps, and error bursts.

"detect anomalies in bad_run"
"find anomalies with severity score above 0.5"

list_bag_topics

List topics in a ROS2 bag file (.db3/.mcap) with message types and counts. No ROS2 installation or message deserialization needed.

"list bag topics in my_recording"

query_bag_messages

Query bag messages filtered by topic and time range. Shows timestamps, topic names, message types, and sizes.

"show messages from /scan topic in my_recording"
"query bag messages from the last 10 seconds"

correlate

Cross-reference log entries with bag topic messages within a time window. Shows what was happening on ROS2 topics around errors. Can correlate logs from one run with a bag from a different run.

"correlate errors in bad_run with bag from bag_recording"
"correlate errors with bag topics, 500ms window"

tail_logs

Tail a log run for new entries since the last check. First call loads the run, subsequent calls return only new entries. Useful for monitoring an active ROS2 system.

"tail my_live_run"
"check for new log entries"

MCP Resources

The server also exposes log data as browsable MCP resources:

Log Path Resolution

The server resolves the log directory using this priority chain:

1. log_dir parameter on the tool call

2. MCP_ROS2_LOGS_DIR env var

3. ROS_LOG_DIR env var

4. $ROS_HOME/log/

5. ~/.ros/log/

It auto-detects whether a path is a single log file, a run directory (contains .log files), a bag directory (contains metadata.yaml), or a log root (contains run subdirectories).

Pagination

All list-returning tools support limit and offset parameters for paginating results. When results are truncated, the output includes a notice with the next offset value. The only exceptions are load_run and compare_runs, which return fixed-structure summaries.

The default limit is controlled by the MCP_ROS2_LOGS_MAX_RESULTS environment variable (default: 100). query_logs and query_bag_messages keep their own default of 50.

# Set a global default limit
claude mcp add --scope user ros2-logs -e MCP_ROS2_LOGS_MAX_RESULTS=50 -e MCP_ROS2_LOGS_DIR=/path/to/logs -- mcp-ros2-logs

Log Format

Parses the standard ROS2 spdlog default format:

[SEVERITY] [EPOCH.NANOSECONDS] [node_name]: message

Example:

[INFO] [1713099970.190824925] [talker_node]: Publishing: Hello World 1
[WARN] [1713099975.443210100] [motion_planner]: Planning timeout after 500ms
[ERROR] [1713099975.501332000] [collision_checker]: No valid trajectory found

Multi-line messages (stack traces) are handled automatically.

Custom Log Formats

If your ROS2 nodes use a custom RCUTILS_CONSOLE_OUTPUT_FORMAT, pass it as an environment variable when registering the MCP server:

claude mcp add --scope user ros2-logs \
  -e RCUTILS_CONSOLE_OUTPUT_FORMAT="{severity} {time} {name}: {message}" \
  -- mcp-ros2-logs

Or for Claude Desktop, add it to the env block:

{
  "mcpServers": {
    "ros2-logs": {
      "command": "mcp-ros2-logs",
      "env": {
        "RCUTILS_CONSOLE_OUTPUT_FORMAT": "{severity} {time} {name}: {message}"
      }
    }
  }
}

Supported placeholders: {severity}, {time}, {name}, {message}, {function_name}, {file_name}, {line_number}.

When {name} is absent from the format, the node name is inferred from the log filename. When {time} is absent, entries are ordered by their position in the file.

Development

git clone https://github.com/spanchal001/mcp-ros2-logs.git
cd mcp-ros2-logs
pdm install
pdm run pytest
pdm run ruff check src/ tests/

License

MIT