pin_message

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

No annotations are provided, so the description carries the full disclosure burden. It does add one genuine behavioral fact beyond the schema (chat-only applicability), but omits permission requirements, idempotency when the message is already pinned, pin-count limits, and whether pinning is visible to all members.

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 sentences, zero filler, with the core action statement front-loaded ahead of the scope caveat and the sourcing hint.

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?

An output schema exists, so return values need no explanation here. For a mutation with two required params and no annotations, however, the description leaves pin-specific semantics (already-pinned behavior, per-chat pin limits, permission errors) unstated.

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 usefully explains where message_id comes from (list_chat_messages), which the schema does not, but chat_id is left entirely unexplained.

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 (pin) and resource (message) plus an explicit scope constraint: chats only, never channels. That constraint alone separates it from channel-oriented siblings like send_channel_message and list_channel_messages.

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?

Gives a clear when/when-not rule ('Only works in chats, not channels') and routes the agent to list_chat_messages to obtain the message_id. It stops short of naming unpin_message as the inverse operation or stating any other precondition.

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