# theory_respell

Suggest the preferred enharmonic spelling for one or more pitches in a given key context. Picks the spelling that is diatonic to the key (e.g. F# in G major, Gb in F major). Uses the key's accidental preference (sharps/flats) as a tiebreaker for chromatic passing tones. WHEN TO USE: after OMR (optical music recognition) to correct mis-spelled accidentals; when generating notation and unsure whether to write F# or Gb; when transposing — respell after the semitone shift to maintain diatonic spelling; before calling notation_render to clean up accidentals. INPUT: { keyContext: string, pitches: string[] } OR { keyContext: string, pitch: string }. Pitch strings use scientific notation: "F#4", "Bb3", "C5", "Eb4". OUTPUT: { ok, requestId, keyContext, results: [{ input, output, changed }], attribution }. changed is true when the spelling was adjusted. EXAMPLES: { keyContext: "F major", pitches: ["F#4", "Bb4", "E4"] } → F#4→Gb4 (Gb is diatonic in F major), Bb4 unchanged, E4 unchanged. { keyContext: "G major", pitch: "Gb4" } → Gb4→F#4 (F# is diatonic in G major).

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

## Facts

- Tool: `theory_respell`
- 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: 3 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `pitch` | string | no | Single pitch string (scientific notation). Use this OR `pitches`. |
| `pitches` | array | no | Array of pitch strings. Use this OR `pitch`. |
| `keyContext` | string | yes | Key signature string, e.g. "C major", "G major", "Bb minor", "F# major". |

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_respell",
    "arguments": {
      "keyContext": "<keyContext>"
    }
  }
}
```

## Why theory_respell is rated Low

This tool purely analyzes and returns spelling suggestions for pitches — it reads/computes information without modifying, executing, or deleting any data. It is a stateless advisory/query operation.

From the tool's own definition: "Suggest the preferred enharmonic spelling for one or more pitches in a given key context"

## Use case

AI agents call theory_respell 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_respell": {}
  }
}
```

## 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_validate_ranges` — Read — https://policylayer.com/tools/com-gradusmusic-notation/theory-validate-ranges.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