discord_add_my_message_reaction

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

Beyond the annotations, it discloses concrete prerequisites — the bot permissions required (View Channel, Read Message History, Add Reactions, Use External Emojis) — which is exactly the kind of auth context annotations cannot express. It also clarifies that duplicate adds are not an error and that the operation is safe to retry, adding nuance to the idempotentHint.

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?

Four short sentences, front-loaded with the core action and followed by format, alternatives, and permissions in a sensible order. The closing 'Changes Discord data; safe to retry' largely duplicates the destructiveHint/idempotentHint annotations, so it is not fully earning its place.

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 3-parameter mutation with an output schema, the description covers the action, the emoji input format, permission requirements, duplicate-call semantics, and sibling routing. Nothing an agent needs in order to call it correctly is missing.

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 all three parameters are already fully documented, including the emoji name:id format. The description's 'Specify unicode characters or custom emojis as name:id' restates what the schema already says, adding no new constraint or edge-case guidance. Baseline 3 applies.

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 opens with a specific verb and resource ('Add a reaction to a message as the bot user'), and the 'as the bot user' qualifier distinguishes it from user-level reaction siblings like discord_delete_user_message_reaction. An agent can identify the operation without opening the schema.

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 explicitly routes to two named siblings with the condition that selects each: discord_list_message_reactions_by_emoji for seeing who reacted, and discord_delete_my_message_reaction for removal. Nothing about alternative selection is left to inference.

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