mastodon-mcp

Create a list

create_list

Create a curated Mastodon list to group accounts, with options to exclude them from your home timeline and set reply policies.

Instructions

Create a curated list. Add accounts to it with add_to_list.

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": {
      "title": "<title>"
    },
    "name": "create_list"
  }
}

Input Schema

Name	Required	Description
`title`	Yes	The list name.
`account`	No	Which connected account to act as. Matches a full handle (alice@example.social), a bare username (alice), or an instance (example.social). Defaults to the first connected account. Call list_accounts to see them.
`exclusive`	No	Hide these accounts from your home timeline, so the list is the only place you see them.
`replies_policy`	No	Whose replies appear in the list timeline. Default 'list', meaning only replies to other list members.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 2, 2026

TDQS

B3.2/5.0

Behavior2/5

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

Annotations already signal this is not read-only, not idempotent, and not destructive. The description merely repeats 'Create' and adds no new behavioral context—no mention of side effects, whether the list starts empty, authorization requirements, or what the response contains. For a mutating tool, this is a gap beyond what annotations cover.

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?

The description is one short sentence plus a practical pointer to add_to_list. It is front-loaded with the core purpose and contains no filler or repetition. Slightly over-concise given the tool has four parameters, but appropriate for a simple creation operation.

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?

The description is adequate for a basic create tool: it names the action and the follow-up operation. However, there is no output schema and no mention of what the call returns or any prerequisite behavior. The workflow hint partially compensates, but an agent might still wonder about response format or required account context.

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 100%, so the schema already documents all four parameters. The description adds no parameter-specific meaning beyond the generic 'curated list' notion. Baseline 3 applies because the schema does the heavy lifting.

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?

The description states a specific verb and resource: 'Create a curated list.' It clearly separates itself from add_to_list by pointing to that sibling for the next step, making the tool's role in the list workflow unambiguous. It does not explicitly differentiate from other list tools like get_lists or delete_list, but the primary purpose is clear.

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?

The description implies a workflow: create a list first, then use add_to_list to populate it. That gives some usage context, but it never states when to choose this tool over alternatives or provides any exclusions. It's an implied usage rather than an explicit guideline.

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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