Create Reaction

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

The description confirms the mutation ('Adds') and matches the readOnlyHint=false annotation. It adds some context by specifying the action's target, but does not disclose behavior such as duplicate handling, authentication requirements, or side-effect scope implied by openWorldHint=true.

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, direct sentence with no redundant words. It is appropriately front-loaded and easy to parse.

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 with three required parameters and an output schema, but the description lacks usage context and fails to explain user_google_email. This is adequate for basic selection but leaves gaps for correct invocation in all scenarios.

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 documents message_id and emoji_unicode, but user_google_email has no description. The tool description adds no parameter information and does not compensate for the undocumented parameter, leaving a gap in the 67% schema coverage.

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 a specific verb ('Adds') and identifies the exact resource ('emoji reaction to a Google Chat message'). This clearly distinguishes the tool from sibling tools like send_message or search_messages.

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?

No guidance is provided on when to use this tool versus alternatives, no prerequisites, and no exclusions. The agent must infer usage solely from the name and schema.

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