send_reaction

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

With no annotations, the description carries the behavioral burden. It usefully discloses that emoji=None/empty removes the reaction and big=true triggers a large animation. However, it does not mention mutation side effects, permission requirements, idempotency, or failure behavior, which keeps it from being more transparent.

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 two compact sentences with the primary action first and the edge-case behaviors second. There is no filler, and every clause adds 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?

For a simple four-parameter tool with an output schema, this is largely complete: it states the operation, the removal edge case, and the big-animation option. It stops short of perfect because it does not explicitly cover prerequisites, possible errors, or the identifier parameters beyond their names.

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 0%, so the description must compensate. It adds meaningful semantics for emoji (null/empty removes the reaction) and big (true means large animation). Chat and message_id are left to their schema names only, which are self-explanatory but not explicitly described.

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 opens with a specific verb and resource: 'Поставить реакцию emoji на сообщение' (set an emoji reaction on a message). It also distinguishes two modes, adding a reaction and removing one, and no sibling tool covers reactions, so there is no ambiguity.

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?

Usage is implied: use this tool when reacting to or unreacting from a message. However, the description never explicitly says when to use it versus alternatives such as send_message or send_file, and it provides no when-not-to-use guidance.

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