Update an entry on your AniList list

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

Annotations already convey write, idempotent, and non-destructive behavior. The description adds '[Requires login]' as an authorization prerequisite and 'Only set the fields you want to change' as partial-update semantics, both of which are beyond the annotation fields. There is no contradiction between the description and the annotations.

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?

The description is only three short clauses, with the action verb and key target front-loaded. Every clause earns its place: auth requirement, exact resource, ID type and source, and partial-update behavior. No redundant or filler content.

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?

Given the 14-parameter schema, output schema, and detailed parameter descriptions, the main description doesn't need to restate field meanings. It supplies the cross-field context an agent needs: login requirement, existing-entry scope, ID sourcing, and partial updates. It is complete enough, though a one-line sibling comparison to add_list_entry/remove_list_entry would make it even stronger.

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 100%, so the baseline is 3. The description adds meaningful context by clarifying that listEntryId is the entry ID (not the media ID) and by pointing to the exact tools that return it. The phrase 'Only set the fields you want to change' also clarifies that all optional parameters are indeed optional partial updates, which is not stated at the schema top level.

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 states 'Update an existing entry on the authenticated user's own AniList list by its list-entry ID', clearly identifying the verb, resource, and scope. It disambiguates from add/remove by saying 'existing entry' and from get_user_list by specifying an update operation. The 'NOT the media ID' caveat further sharpens the purpose.

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?

It provides clear conditions: requires login, updates the authenticated user's own list, and applies to existing entries. It also tells the agent where to obtain the correct listEntryId (get_user_list or add_list_entry's response) and warns against using the media ID. It doesn't explicitly contrast with add_list_entry or remove_list_entry, but the context strongly implies when this tool should be used.

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