discord_list_reactions

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds that the result is the set of reacting users for a single emoji, which is useful because there is no output schema, but it omits pagination behavior and whether the caller's own reactions are included.

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 well-formed sentence that front-loads the operation and its scope. Nothing is redundant and no filler is present.

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 4-parameter read tool with no annotations gaps and no output schema, the description covers the core intent and emoji format, but leaves the limit parameter and the ordering/pagination of returned users unaddressed, which an agent may 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 coverage is 50%: channel_id and message_id are described in-schema, while emoji and limit are not. The description compensates for emoji by specifying accepted formats ('unicode or name:id'), but leaves the limit parameter's behavior (max users returned, ordering) entirely unexplained.

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 ('List'), resource ('the users who reacted to a message'), and the scoping constraint ('with one emoji'), which clearly separates it from mutation siblings like discord_add_reaction and discord_remove_reaction. It is clear but never explicitly differentiates itself from those siblings in text.

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 statement of when to use this tool versus alternatives, no prerequisites (e.g., permissions to view reactions), and no guidance on the 'limit' parameter or pagination. The agent must infer usage purely from the name.

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