Assign a media item as the cover for a gallery item by updating its cover_media_id; use attach_gallery_media separately to add a cover-role gallery_item_media row.
Set gallery_items.cover_media_id. Use attach_gallery_media separately if you also want a gallery_item_media row with role=cover.
| Name | Required | Description | Default |
|---|---|---|---|
| item_id | Yes | ||
| media_id | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It usefully discloses the data-model effect on gallery_items.cover_media_id and the distinction from attach_gallery_media, but does not state overwrite semantics, required permissions, or error behavior for a mutation tool.
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?
Two sentences, zero waste, and the core operation is front-loaded before the sibling-tool caveat. Every sentence carries useful information.
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?
For a simple two-parameter setter with no annotations and no output schema, the description establishes scope and the key sibling distinction. However, with 0% schema description coverage, it should do more to define the required parameters and mutation side effects.
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 0% for two required UUID parameters. The description names cover_media_id and implies media_id, but does not explain item_id, what entity each UUID references, or any constraints, so it only partially compensates for the schema gap.
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?
States a specific verb ('Set') and exact target ('gallery_items.cover_media_id'), and explicitly distinguishes itself from the sibling attach_gallery_media by describing the extra row that sibling creates.
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?
Provides clear routing guidance: use attach_gallery_media separately if a gallery_item_media row with role=cover is also needed. It does not spell out when this tool should not be used, but the alternative condition is explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.