woow_emqx_mcp_server

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Read EMQX Trace Log

emqx_get_trace_log

Read-onlyIdempotent

Retrieve log entries captured by an EMQX trace. Reads the buffered trace events even after the trace finishes, with optional truncation limit.

Instructions

Read what a trace captured.

A trace that is still running usually returns little or nothing — its events sit in an in-memory buffer until the trace expires.

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": {
      "name": "<name>"
    },
    "name": "emqx_get_trace_log"
  }
}

Input Schema

Name	Required	Description	Default
`name`	Yes	Trace name to read.
`max_bytes`	No	Truncate the log at this many bytes.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 3, 2026

TDQS

A4.5/5.0

Behavior5/5

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

Beyond annotations readOnlyHint=true, idempotentHint=true, destructiveHint=false, the description discloses the in-memory buffering behavior and the fact that running traces typically return little data. This is non-obvious behavioral context not captured by annotations.

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?

Two short sentences; the first states the core function, the second adds a critical timing caveat. No redundant filler, and the key information is front-loaded.

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

Completeness5/5

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

With an output schema present, return values are documented. The tool is simple (name + max_bytes), and the description covers the key behavioral nuance about running traces. Sufficient for an agent to select and invoke correctly.

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

Parameters3/5

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

Schema covers both parameters with descriptions (100% coverage). The description doesn't elaborate on the parameters, so it adds no extra semantic meaning. Baseline 3 is appropriate when the schema does the heavy lifting.

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

Purpose5/5

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

The description uses the specific verb 'Read' and the resource 'what a trace captured', clearly distinguishing from sibling tools like emqx_list_traces (which lists trace metadata) and emqx_create_trace/emqx_delete_trace. It immediately conveys the tool's function.

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

Usage Guidelines4/5

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

The description notes that running traces return little or nothing and that events remain buffered until expiry, implying the tool is most useful after a trace finishes. This gives contextual guidance but doesn't explicitly name alternatives or state when not to use it.

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