reactions

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

No annotations are provided, so the description carries the full behavioral burden, and it discloses almost nothing: no indication of whether authentication is required, whether the read is safe/non-mutating, how results are ordered, or whether pagination applies. 'List' weakly implies a read, but this is not stated.

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?

A single short sentence with no filler and the key information front-loaded. It is efficient, though its brevity is as much under-specification as conciseness.

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?

With no annotations and no output schema, the description should explain how the target message is identified and what the reaction list looks like. It does neither, leaving a zero-parameter read tool ambiguous about its input context.

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 declares zero parameters with 100% coverage, which normally sets a baseline of 4, but the description refers to 'a message' as the target while offering no parameter or mechanism to identify that message. That ambiguity between description and empty schema reduces the score below baseline.

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 gives a specific verb and resource ('List the reactions') plus a scope ('on a message'), so the agent knows this reads reactions rather than creating one. It is clearly distinct from the sibling 'react' (which adds a reaction), though it never names that sibling to make the distinction explicit.

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?

There is no guidance on when to use this versus 'react', 'messages', or 'read', and no mention of prerequisites or the context in which the target message is determined. The agent must infer usage entirely.

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