PostFader V12 — FL Studio MCP Server

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pattern_list

Read-onlyIdempotent

Lists all patterns in an FL Studio project with name, color, length, current status, and default-empty flag, helping you choose pattern numbers for editing tools.

Instructions

List the project's patterns with name, color, length, and which is current.

Read-only. Also reports whether each pattern is FL's default empty pattern.
Use pattern numbers with pattern_set, channel_get_steps, and the piano_roll
tools; use pattern_create to make a new named pattern.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Default
`patterns`	Yes
`warnings`	No
`observed_at`	Yes
`schema_version`	No	1.0
`observation_atomic`	No
`project_dirty_flag`	No
`current_pattern_number`	Yes
`maximum_pattern_number`	Yes
`reported_pattern_count`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv11.0.2Oct 5, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false; the description reinforces read-only but goes further by noting it reports whether each pattern is FL's default empty pattern, a non-obvious behavioral detail. It could add more about ordering or empty-project behavior, so not a 5.

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 purpose and followed by behavioral and usage notes. Efficient and well-organized, with minimal waste.

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 no-parameter list tool with an output schema present, the description covers purpose, read-only nature, the default-empty-pattern flag, and integration with sibling tools. Context is sufficient for correct invocation, though ordering/details are not mentioned.

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

Parameters4/5

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

Zero parameters, so baseline is 4. The description usefully names the fields returned (name, color, length, current), which helps an agent understand what data is available even though no input parameters exist.

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?

Clearly states verb+resource: 'List the project's patterns' and names the reported fields (name, color, length, current). It also distinguishes itself from siblings pattern_create and pattern_set by explaining its read-only listing role and how the returned pattern numbers are consumed.

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?

Explicitly says to use the returned pattern numbers with pattern_set, channel_get_steps, and the piano_roll tools, and routes creation to pattern_create. It gives clear context for when to use this tool versus creation/setting tools, but doesn't state when-not to use it or exclusions.

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

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