character-forge-mcp

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Background theme (music)

character_theme

Generates an instrumental leitmotif from a saved theme composition plan and saves it as assets/theme.mp3; confirm ElevenLabs Music cost before running.

Instructions

ONLY on request, after a theme prompt is saved (character_prompt kind "theme" → character_prompt_save). Generates the instrumental leitmotif from its composition plan with ElevenLabs Music v2.5 ($0.60 per started minute: a 30 s theme costs $0.60) and saves assets/theme.mp3. Confirm the cost with the user first.

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": {
      "id": "<id>"
    },
    "name": "character_theme"
  }
}

Input Schema

Name	Required	Description	Default
`id`	Yes
`seed`	No	Same seed + same plan gives a similar result.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.1Nov 12, 2026

TDQS

A4.2/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does so well: it discloses the paid model, the exact pricing model and a worked example ($0.60 per started minute; 30 s costs $0.60), the destination file, and the requirement to confirm spend with the user. It stops short of covering failure modes, overwrite behavior for an existing assets/theme.mp3, or generation latency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, with the most consequential constraint ('ONLY on request') front-loaded and cost placed before the asset note. Nothing is redundant, though the parenthetical prerequisite chain is dense enough to slow a first read.

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

Completeness4/5

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

For a 2-parameter generation tool with no output schema, most of what an agent needs is present: precondition, price, and the resulting artifact path stand in for a return-value contract. The remaining hole is the meaning of the required 'id' parameter, which neither schema nor description resolves.

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

Parameters2/5

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

Schema coverage is only 50%: 'seed' is documented inline, but 'id' has no schema description and the description never says what it identifies (a character, a prompt record, or a plan). The phrase 'from its composition plan' hints at a linkage but adds no usable semantics for the one required parameter, so compensation for the coverage gap is weak.

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?

States a specific verb and artifact: 'Generates the instrumental leitmotif from its composition plan with ElevenLabs Music v2.5 ... and saves assets/theme.mp3.' The named engine, the input (composition plan) and the concrete output file distinguish it cleanly from audio-adjacent siblings like character_voice or character_video.

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

Usage Guidelines5/5

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

Explicitly gates invocation: 'ONLY on request, after a theme prompt is saved', names the prerequisite tool and the required prompt kind (character_prompt kind "theme" → character_prompt_save), and adds 'Confirm the cost with the user first.' That is a full when-to-use plus a hard precondition rather than an inferred one.

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