Predictive Maintenance MCP Server

generate_fft_report

Generate an interactive FFT spectrum report with peak detection and harmonic labeling from a stored vibration signal, saving a timestamped HTML file for machinery fault analysis.

Instructions

Generate an interactive FFT spectrum report (HTML) for a stored signal.

Saves a self-contained Plotly HTML report (spectrum in dB, automatic
peak detection, harmonic labels) to the reports/ directory with a
timestamped filename — consecutive runs produce distinct files.
Requires the signal loaded via load_signal() first; the sampling
rate comes from the stored signal metadata.

Args:
    signal_id: ID of the stored signal (from load_signal).
    max_freq: Maximum frequency to display (Hz). Default 5000 Hz
    num_peaks: Number of peaks to detect and label. Default 15
    rpm: Optional shaft speed in RPM — peaks at integer multiples
        of rpm/60 Hz are labeled as 1x/2x/... harmonics.
    ctx: MCP context. Unused — see this module's docstring on logging.

Returns:
    Dictionary with file path, metadata, and summary (NO HTML content)

Raises:
    ValueError: If the signal_id is not loaded, or the stored signal
        has no sampling rate.

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": {
      "signal_id": "<signal_id>"
    },
    "name": "generate_fft_report"
  }
}

Input Schema

Name	Required	Description	Default
`rpm`	No
`max_freq`	No
`num_peaks`	No
`signal_id`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedv0.9.1Jul 15, 2026

removedInput schema / properties / rotation_freq

Removed value: -{
-  "anyOf": [
-    {
-      "type": "number"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "title": "Rotation Freq"
-}

addedInput schema / properties / rpm

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Rpm"
+}

removedInput schema / properties / sampling_rate

Removed value: -{
-  "anyOf": [
-    {
-      "type": "number"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "title": "Sampling Rate"
-}

removedInput schema / properties / signal_file

Removed value: -{
-  "title": "Signal File",
-  "type": "string"
-}

addedInput schema / properties / signal_id

Added value: +{
+  "title": "Signal Id",
+  "type": "string"
+}

changedInput schema / required

Previous value: -[
-  "signal_file"
-]New value: +[
+  "signal_id"
+]

First observedv0.8.0May 26, 2026

TDQS

A4.8/5.0

Behavior5/5

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

No annotations are provided, so the description carries the full burden. It discloses that the tool saves a self-contained Plotly HTML report to reports/ with timestamped filenames, consecutive runs produce distinct files, and the return value contains no HTML content (just path, metadata, summary). It also documents error conditions (ValueError for unloaded signal or missing sampling rate). This is extensive behavioral disclosure beyond what the schema provides.

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?

The description is well-structured with a one-sentence summary, a prerequisite note, then Args/Returns/Raises sections. Every sentence adds useful information: file naming behavior, sampling rate source, parameter meanings, return structure, and error conditions. No fluff or redundancy.

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?

Given the tool's complexity (4 parameters, no annotations), the description fully covers the prerequisite (loaded signal), the output behavior (file path, metadata, summary), error conditions, and parameter semantics. It is complete enough for an agent to invoke the tool correctly and interpret the result without additional context.

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

Parameters5/5

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

The schema has 0% description coverage, but the description compensates fully with an Args section explaining each parameter: signal_id, max_freq (with default), num_peaks (with default), rpm (with harmonic labeling semantics), and ctx (unused). It adds meaning beyond the schema by explaining the harmonic labeling behavior (rpm/60 Hz multiples as 1x/2x/...) and the default values for max_freq and num_peaks.

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 begins with a specific verb and resource: 'Generate an interactive FFT spectrum report (HTML) for a stored signal.' This clearly distinguishes it from sibling report generators (envelope, ISO, PCA, etc.) by naming the FFT spectrum focus. The phrase 'FFT spectrum report' is unambiguous and aligns with the tool name.

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 states a clear prerequisite: 'Requires the signal loaded via load_signal() first; the sampling rate comes from the stored signal metadata.' This gives the agent context on when the tool can be invoked. However, it doesn't explicitly contrast with alternatives like generate_envelope_report or analyze_fft, so it lacks explicit exclusions/alternative guidance. The context is strong enough to warrant a 4 rather than 3.

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