discord_react

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering the safety profile. The description adds one genuinely useful behavioral fact beyond that: the reaction is the bot's own identity, not an arbitrary user's. It says nothing about rate limits or permission requirements, so it goes modestly past the annotations but not far.

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?

Two short sentences with the operation front-loaded and no preamble. The trailing 'Returns: Confirmation.' is largely redundant given the output schema exists, costing it a point.

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 simple reaction mutation with annotations and an output schema present, the description covers the essentials and the identity-scoping constraint. Remaining gaps are the undocumented message_id parameter and the absence of any when-to-use or permission context, which keeps it short of a 5.

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%: emoji and channel_id are documented in the schema, while message_id and action are not. The description's 'add or remove' maps loosely to the action enum but adds no new detail on message_id or emoji format. Marginal compensation for the coverage gap, so baseline 3 is appropriate.

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?

States a specific verb pair (add/remove) and resource (reaction on a message), and uniquely scopes it to 'the bot's own reaction'. No sibling tool manipulates reactions, so the resource alone distinguishes it from discord_send_message, discord_edit_message, and the rest of the message family.

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?

The description implies usage via 'add or remove' but never states when to call this versus alternatives (e.g., reacting vs. replying), nor any prerequisites like needing the message to exist or the bot having channel access. Usage is inferable but not guided.

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