add_reaction

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

Annotations already indicate a non-readOnly, non-destructive mutation. The description adds no further behavioral details, such as idempotency, visibility, or permission requirements. It merely restates the action.

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?

The description is a single sentence that immediately conveys the action and resource, with a helpful example. No unnecessary words; structurally efficient.

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 tool's simplicity and the presence of an output schema, the description is minimally adequate. However, it omits important contextual details like required permissions or error scenarios, leaving gaps for robust agent reasoning.

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?

With 0% schema description coverage, the description partially compensates by giving an example for the `emoji` parameter (`:thumbsup:`). However, it offers no explanation for `message_id`, which remains ambiguous. Adds some meaning but incomplete.

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 clearly states the action (add) and resource (emoji reaction to a message), with an example (`:thumbsup:`) that reinforces the purpose. No other sibling tool performs a similar function, so it is well-distinguished.

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 provides no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. It only states what it does, leaving the agent without context for optimal utilization.

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