Create Reaction

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

Annotations already indicate this is a non-read-only, non-idempotent, non-destructive operation, and the description aligns with that. However, the description adds no extra behavioral context beyond the core action, such as the reaction being publicly visible to space members, duplicate-reaction behavior, or any authorization requirements. It is adequate but not informative beyond the annotations.

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 states the action and target. Every word contributes value and there is no filler or repetition of the title.

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?

The tool is simple and an output schema exists, so the description does not need to cover return values. However, the required user_google_email parameter is left ambiguous in both the schema and the description, and no usage context (e.g., acting as a specific user or needing space membership) is provided. The description is minimally viable but has clear gaps.

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?

The schema describes message_id and emoji_unicode, but user_google_email has no schema description. The tool description does not explain any parameters or compensate for the undocumented required field. Since schema coverage is only 67% and the description adds no param-level meaning, the agent is left to guess the role of user_google_email.

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 ('Adds') with a specific resource ('emoji reaction') and target ('Google Chat message'). It is immediately clear what the tool does and it distinguishes itself from all sibling tools, none of which mention reactions.

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 clear context: the tool is for adding an emoji reaction to a Chat message. No sibling tool performs this action, so no exclusions or alternatives need to be named. It falls short of a 5 only because it does not explicitly state when not to use it or mention related Chat tools.

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