# theory_validate_ranges

Check every note in a Score JSON against its instrument's standard practical range. Returns warnings for out-of-range pitches with measure, beat, MIDI number, and severity. WHEN TO USE: after parsing a MusicXML file with theory_parse_xml and before analysis — catch unplayable or extreme notes early; when generating or editing a score programmatically and want to verify instrument idiomatic range; when a student submits a composition for critique and range errors should be flagged. SEVERITY LEVELS: "error" = note is > 1 semitone outside the practical range; "warn" = note is at the boundary (within 1 semitone). SUPPORTED INSTRUMENTS (partial name match, case-insensitive): Violin, Viola, Cello, Double Bass, Harp, Flute, Piccolo, Oboe, English Horn, Clarinet, Bass Clarinet, Bassoon, Contrabassoon, Soprano/Alto/Tenor/Baritone Sax, Horn, Trumpet, Trombone, Tuba, Piano, Organ, Marimba, Xylophone, Vibraphone, Glockenspiel, Timpani, Soprano/Mezzo/Alto/Tenor/Baritone/Bass (voice). INPUT: a maestroAnalyst Score object — obtain one by calling theory_parse_xml with MusicXML text. OUTPUT: { ok, requestId, warnings: [{ measure, beat, pitch, midi, partId, instrumentName, min, max, severity }], attribution }. Empty warnings array means all notes are in range. EXAMPLE: pass a Score with a Violin part containing a note at A7 (MIDI 105) — it will return severity "error" since violin tops out around B7/MIDI 107 but A7 is beyond practical range.

Agent View of the PolicyLayer registry record for `theory_validate_ranges`. HTML page: https://policylayer.com/tools/com-gradusmusic-notation/theory-validate-ranges

## Facts

- Tool: `theory_validate_ranges`
- Server: Gradus Notation (`@gradusmusic/notation-mcp`) — https://policylayer.com/tools/com-gradusmusic-notation.md
- Install: `npx -y @gradusmusic/notation-mcp`
- Homepage: https://github.com/delmas41/gradusnotation
- Risk category: Read (Low risk)
- Registry record: grade C, identity unverified
- Server rate-limited: no
- Parameters: 5 (2 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `notes` | array | yes | Flat array of Note objects from a Score. |
| `parts` | array | yes | Array of PartInfo objects ({ id, name }). |
| `measureCount` | integer | no |  |
| `keySignatures` | array | no |  |
| `timeSignatures` | array | no |  |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "theory_validate_ranges",
    "arguments": {
      "notes": [],
      "parts": []
    }
  }
}
```

## Why theory_validate_ranges is rated Low

This is purely an analytical/validation tool that inspects data (a Score JSON) and returns informational warnings about range compliance. It has no side effects on the score or any external system. It reads and reports; it does not write, execute arbitrary code, delete data, or commit financial transactions.

From the tool's own definition: "Tool checks/validates notes against ranges and returns warnings; description states 'Check every note in a Score JSON against its instrument's standard practical range. Returns warnings for out-of-range pitches'."

Risk signals: Bulk/mass operation — affects multiple targets

## Use case

AI agents call theory_validate_ranges to retrieve information from Gradus Notation without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Gradus Notation:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "theory_validate_ranges": {}
  }
}
```

## Other tools on Gradus Notation (9)

- `knowledge_search` — Read — https://policylayer.com/tools/com-gradusmusic-notation/knowledge-search.md
- `notation_examples` — Read — https://policylayer.com/tools/com-gradusmusic-notation/notation-examples.md
- `notation_render` — Read — https://policylayer.com/tools/com-gradusmusic-notation/notation-render.md
- `notation_schema` — Read — https://policylayer.com/tools/com-gradusmusic-notation/notation-schema.md
- `notation_validate` — Read — https://policylayer.com/tools/com-gradusmusic-notation/notation-validate.md
- `theory_analyze_score` — Read — https://policylayer.com/tools/com-gradusmusic-notation/theory-analyze-score.md
- `theory_parse_xml` — Read — https://policylayer.com/tools/com-gradusmusic-notation/theory-parse-xml.md
- `theory_pitch_utils` — Read — https://policylayer.com/tools/com-gradusmusic-notation/theory-pitch-utils.md
- `theory_respell` — Read — https://policylayer.com/tools/com-gradusmusic-notation/theory-respell.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=com-gradusmusic-notation · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-gradusmusic-notation