trace_start

[solution]

Starts a long-running command under the workspace and stores an active GliderTrace runtime session.

Before you use this tool

Executes commands with your local permissions. Commands can change workspace files and contact package sources. Check the workspace and runner policy. Starts a local process that remains active until trace_stop or external termination.

Try it locally in the GliderTrace playground

Parameters

Name	Type	Required	Description
command	string	Yes	Command executable to run.
arguments	json	No	Optional command arguments.
workingDirectory	string	No	Optional working directory under the workspace root. Defaults to the workspace root.
environment	json	No	Optional environment variables to set for the command process.
captureStdout	boolean	No	Capture stdout as a sensitive artifact on trace_stop. Defaults to true. Default: `true`
captureStderr	boolean	No	Capture stderr as a sensitive artifact on trace_stop. Defaults to true. Default: `true`
collectTrace	boolean	No	Collect a runtime.nettrace artifact with built-in EventPipe collection. Defaults to true. Default: `true`
label	string	No	Optional short label for the stored session, for example nightly-baseline. Use it to find the session again with trace_list_sessions. Maximum 128 characters.

Examples

Replace sample paths and symbol keys with values from your workspace.

Start a long-running app session

Arguments 
{
  "command": "dotnet",
  "arguments": [
    "run"
  ]
}

Full MCP request

Full MCP request 
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "trace_start",
    "arguments": {
      "command": "dotnet",
      "arguments": [
        "run"
      ]
    }
  }
}

Response Notes

Returns active session metadata and process details for a later trace_stop call.

GliderTrace 1.0.0 returns compact JSON for every tool. Result fields appear beside success; there is no response-format parameter. success describes the tool call. Check the process or session status and exitCode separately. Scalar results and fields that conflict with reserved names appear under result.

To migrate an envelope consumer, read response.sessionId instead of response.data.sessionId. Stored sessions and exported files keep their formats. --max-response-chars limits response text to 60,000 UTF-16 characters by default. Use 0 to disable it, or at least 1,000. This limit counts text characters, not transport bytes or tokens.

outputLimit.truncated marks omitted response detail. It does not change capture completeness. Use the returned next tool and arguments when available. Do not repeat a command or feedback submission to recover omitted output. For event pages, keep the filters and cursor while reducing limit.

For session details, set includeArtifacts and includeTopFindings to false to reduce output. Check error, actionable meta, warnings, and coverage before drawing conclusions. Internal diagnostics stay in local server logs.