Add a VRChat user, avatar, world, or VRC+ world to a favorite group by specifying the target ID and group tags.
Add a user, avatar, or world to a favorite group.
| Name | Required | Description | Default |
|---|---|---|---|
| tags | Yes | Collection names returned by favorites view=groups; use their type too. | |
| type | Yes | ||
| targetId | Yes | User/avatar/world ID to favorite. |
| Name | Required | Description | Default |
|---|---|---|---|
| result | No | ||
| status | Yes | ||
| favorite | No |
Changes observed during successful MCP inspections.
v0.1.15Input schema / properties / tags / descriptionPrevious value: -"Favorite group tags, e.g. worlds1, avatars1, group_0."New value: +"Collection names returned by favorites view=groups; use their type too."Input schema / properties / type / enumPrevious value: -[
- "avatar",
- "friend",
- "world"
-]New value: +[
+ "avatar",
+ "friend",
+ "vrcPlusWorld",
+ "world"
+]v0.1.8Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The only annotation is readOnlyHint=false, consistent with a write, and the description adds no behavioral context beyond it. It does not say what happens if the target is already favorited (idempotency/duplicate behavior), whether the tags collection must already exist, or any rate/permission constraints.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tight sentence with no filler and the action front-loaded. It is efficient, though arguably too terse to carry the mutation's semantics.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
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 described, and the operation is simple. However, for a mutation with only a readOnlyHint=false annotation, the description omits duplicate-handling and tag-creation semantics that an agent would need to call it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 67% and the schema already explains 'tags' (collection names from favorites view=groups) and 'targetId'. The description loosely paraphrases the type enum as 'user, avatar, or world', which does not match the actual enum values ('friend', 'vrcPlusWorld'), adding little and slightly muddying the 'type' parameter.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description gives a specific verb ('Add') and resource types ('user, avatar, or world') directed at a 'favorite group', which is enough to distinguish it from siblings like vrchat_favorites (listing) and vrchat_favorite_remove (removal). It does not explicitly name those siblings, so it falls 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.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no explicit when-to-use guidance, no mention of the remove/list alternatives, and no preconditions such as needing an existing favorite group or the auth state. Usage is only implied by the verb 'Add'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.