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

Annotations already declare read-only, idempotent, non-destructive, and open-world hints, so the description's claim 'Reads only; no reaction is added or removed' is redundant but not contradictory. It adds valuable context: requires API key, zero counts are a real answer, and it returns both counts and caller's own reactions, which are not in 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 four sentences, each contributing distinct value: purpose, use-case, safety/authorization, and return semantics. No redundancy or fluff.

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?

Given the tool's simplicity (one parameter, no output schema), the description covers purpose, usage, safety, and return meaning. No output schema means the agent needs to know what to expect, and the description specifies counts per type and caller's reactions. Completeness is high for 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?

The single parameter is fully described in the schema (UUID of article, from article tools' id field). The description adds usage context by explaining the tool works on one article at a time, and confirms the parameter is the article_id. Since schema coverage is 100%, the baseline is 3, but the description enriches the parameter semantics by tying it to the workflow.

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 tool reads article reactions, specifying both total counts and the authenticated account's reactions. It distinguishes from siblings like add_reaction and remove_reaction by emphasizing it is a read operation.

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?

Explicit guidance: use before add_reaction or remove_reaction to determine current state (e.g., already liked vs. not liked). It also states it covers one article at a time, which sets expectations for batch operations.

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