headrush-mcp

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get_block

Read-only

Read a HeadRush pedal block's current parameter values as normalized 0–1 numbers, or use display to return pedal-style values and option names.

Instructions

Read a block's current values. Numbers are normalized 0-1.

With display, values read as on the pedal, like "-3.0 dB", and options by name. A number with an unknown curve stays 0-1.

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": {
      "block": "<block>"
    },
    "name": "get_block"
  }
}

Input Schema

Name	Required	Description	Default
`block`	Yes
`display`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 9, 2026

TDQS

A3.6/5.0

Behavior4/5

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

Annotations already establish this as a safe read (readOnlyHint=true, openWorldHint=false), and the description adds real behavioral detail beyond them: values are normalized 0-1, `display` renders unit-formatted strings like "-3.0 dB", options appear by name, and numbers with unknown curves remain 0-1. That undocumented edge-case behavior is genuinely useful context an agent could not infer from the annotations or schema.

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?

Two short sentences, front-loaded with the core action and followed by the modifier behavior. No filler. The trailing line about unknown curves is slightly orphaned but still earns its place as an edge-case note.

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

Completeness3/5

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

An output schema exists, so the return format need not be described, and the normalization/display behavior is covered. What's missing for a 2-parameter read tool is the identity of the `block` argument and any note on how this differs from `describe_block`, which an agent needs before calling.

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 description coverage is 0%, so the description must carry the load. It explains `display` well (pedal-style formatting, options by name, unknown-curve fallback) but says nothing about what `block` accepts — name, index, or ID — which is the required parameter and the most important thing to get right.

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

Purpose4/5

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

States a specific verb and resource: 'Read a block's current values.' An agent knows it retrieves parameter values for a block rather than metadata. However, it never distinguishes itself from the sibling `describe_block` or `list_blocks`, leaving ambiguity about which one returns current values versus static descriptions.

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

Usage Guidelines3/5

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

Usage is only implied — the tool reads current values, and the `display` flag is described as a formatting choice. There is no explicit guidance on when to prefer this over `describe_block`, `list_blocks`, or the setters like `set_block_params`, and no prerequisites (e.g., a rig must be loaded) are mentioned.

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