Reply to a message

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

Annotations already declare readOnlyHint=false (write) and destructiveHint=false (non-destructive). The description adds the quoting behavior and the same-account/same-chat constraint, which are not in annotations. But it doesn't disclose other behavioral aspects like auth requirements, side effects beyond sending, or what happens to the original message. With annotations covering the safety profile, this is adequate but not rich.

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 a single, tightly worded sentence that front-loads the core action and constraint. No filler words; every phrase adds information (reply, quote, same chat, same account, works in direct chats and groups). It is an example of concise, efficient writing.

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 reply tool, the description covers the essential use case and scope. It does not mention the return value (no output schema exists) or any edge cases, but given the schema covers all parameters and the annotations cover safety, an agent has enough to call it correctly. A small gap is the lack of any note about the response, but this is minor.

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 fully documents all three parameters including the optional idempotencyKey semantics. The description does not add any additional meaning about parameters, such as format hints or relationships. Since the schema carries the full burden, the baseline of 3 applies.

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 states a specific verb ('Reply') with a resource ('a message'), and adds the distinguishing feature of quoting the original message. It also specifies scope: 'in the same chat and from the same account' and 'direct chats and groups', which clearly separates it from siblings like send_text (which sends without quoting) and edit_message (which modifies).

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?

It gives clear context: use this when you need to reply with a quoted message. It specifies the chat/account scope and that it works in both direct chats and groups. However, it does not explicitly name alternatives or state when NOT to use it (e.g., for a plain message without quoting, send_text would be appropriate). The guidance is clear but lacks explicit exclusion.

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