slack_get_reactions

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

Annotations already declare readOnlyHint=true and openWorldHint=true, yet the description adds real behavioral context beyond them: the required scopes (reactions:read, users:read) and the fact that user lists can be partial, flagged by users_complete. The partial-data warning is exactly the kind of caveat annotations cannot express.

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?

Two short sentences, zero filler, front-loaded with what is returned and followed by the prerequisite scopes. Every clause carries information.

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?

Return values are covered by the output schema and safety by the annotations, and permissions are stated. But with three undocumented required parameters and no format guidance for ts, an agent can still mis-call it; the description is adequate rather than complete.

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?

All three required parameters (workspace, channel_id, ts) have 0% schema description coverage, so the description carries the full burden. It does not explain any of them, and in particular gives no hint about the ts message-timestamp format, which is the one parameter an agent is most likely to get wrong.

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?

States a specific verb and resource ('Get message reaction names, counts and users') and names the fields returned, which separates it from the write-side siblings slack_add_reaction and slack_remove_reaction by implication. It stops short of explicitly contrasting itself with those siblings, so it is clear but not sibling-differentiated.

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 explicit when-to-use or when-not-to-use statement and no named alternative. Usage is only implied by the name and the returned fields: an agent infers this is the read counterpart to add/remove reaction. That is implied usage, not guidance.

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