mastodon-mcp-server

List Create

list_create

Create a new Mastodon list with a title and optional replies policy to group accounts and control reply visibility in timelines.

Instructions

Create a new list.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`title`	Yes	Title of the list.
`replies_policy`	No	'followed', 'list', or 'none' (default 'list').	list

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv1.0.5Sep 12, 2026

addedInput schema / additionalProperties
```
Added value: +false
```
addedInput schema / properties / replies_policy / default
```
Added value: +"list"
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "result": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "result"
+  ],
+  "type": "object",
+  "x-fastmcp-wrap-result": true
+}

First observedv1.0.1Jun 26, 2026

TDQS

C2.9/5.0

Behavior2/5

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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, open-world mutation. The description adds nothing beyond that: no auth/permission requirements, no statement about what replies_policy controls, and no indication of what happens on creation. For a write tool it carries little extra context.

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?

A single front-loaded sentence with zero filler. It is efficient, though its brevity borders on under-specification rather than deliberate conciseness.

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

Completeness2/5

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

An output schema exists, so return values need not be explained, but for a mutation tool with minimal annotations the description leaves key gaps: what kind of list this is, whether it requires authentication, and why/when to set replies_policy. The definition is too thin for the operation's 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 both parameters are already documented in the schema, which sets the baseline at 3. The description adds no meaning beyond the schema for title or replies_policy.

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 new list"), making the operation unambiguous. However, it offers no differentiation from siblings like lists_get or list_delete, and does not clarify the domain meaning of "list" (a curated account list), so it stops short of a 5.

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

Usage Guidelines2/5

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

There is no guidance on when to use this tool, no prerequisites, and no mention of alternatives (e.g. list_accounts_add for populating an existing list). The agent must infer usage entirely from the name.

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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