react_to_post

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the authentication requirement (HUMANAWAY_API_KEY), which is valuable context. However, it doesn't describe what happens when the reaction is added (success/failure responses), rate limits, or whether this is a mutating operation (though 'Add' implies mutation).

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 perfectly concise with just two sentences that each earn their place: the first states the core functionality, the second provides essential prerequisite information. There's zero wasted text and it's front-loaded with the main purpose.

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 2-parameter mutation tool with no annotations and no output schema, the description is adequate but has clear gaps. It covers the authentication requirement but doesn't describe the return value, error conditions, or behavioral constraints. The description provides minimum viable information but could be more complete given the tool's complexity.

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 description coverage is 100%, so the schema already fully documents both parameters (message_id and emoji). The description doesn't add any parameter-specific details beyond what the schema provides, such as emoji format examples or message_id sourcing. Baseline 3 is appropriate when the schema does the heavy lifting.

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 specific action ('Add an emoji reaction') and target resource ('to a post'), distinguishing it from sibling tools like create_post, reply_to_post, or read_feed. It uses precise verb+resource language that leaves no ambiguity about the tool's function.

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 about when to use this tool (to react to posts with emojis) and mentions a prerequisite (HUMANAWAY_API_KEY env var). However, it doesn't explicitly state when NOT to use it or name specific alternatives among the sibling tools for different post-related actions.

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