mdl_custom_lists_add_item

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

Annotations already declare non-read-only, non-idempotent, non-destructive behavior. The description adds genuinely useful context beyond that: it requires host-configured MyDramaList authentication and mutates remote data, so the agent understands the auth prerequisite and side-effect scope.

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?

Three short, front-loaded sentences with no filler. The action, auth requirement, and usage restriction are all immediately visible.

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 mutation tool with no output schema, the description adequately covers auth and side-effect expectations, but with 0% parameter coverage and no return-value guidance, an agent still lacks enough to call it confidently in edge cases.

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% and neither parameter has documentation in the schema. The description adds no explanation of list_id or entry_id (e.g., valid formats, where the list id comes from), so it fails to compensate for the coverage gap even though the names are somewhat self-evident.

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 a specific verb and resource ('Custom Lists: add item'), making it clearly distinguishable from siblings like mdl_custom_lists_remove_item and mdl_custom_lists_sort_item. It is clear but does not explicitly call out the siblings it differs from.

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 a concrete usage condition: 'use only for an explicit user request,' which tells the agent when this mutation is appropriate. It stops short of naming alternatives (e.g., remove_item) or describing preconditions like the list existing.

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