react_to_message

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

Discloses that each account can have at most one reaction per message, calling again replaces the previous one, and setting remove=true retracts an existing reaction. No annotations provided, so full burden is on description.

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?

Single paragraph starting with main action, then parameter rules, then usage guidance. Every sentence adds value with no redundancy.

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 complexity of the tool (6 parameters, 3 required, conditional logic), the description covers all behavioral aspects, parameter constraints, and usage context. No output schema, but description is self-contained.

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?

Adds meaning beyond schema by explaining that exactly one of recipient/group_id is required, that emoji is still required for removal, and clarifies the roles of target_author and target_timestamp. Schema coverage is 100%, but description adds significant context.

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 uses specific verbs 'add or remove' and resource 'emoji reaction', and explicitly distinguishes from sending text replies by naming alternatives send_message and send_group_message.

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?

Clearly states when to use (reacting without sending a reply), when not to use (for text replies), and gives exact alternative tools. Also notes the requirement of exactly one of recipient or group_id.

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