Pin or unpin a specific message inside a chat using its message ID, making key content stand out. Optionally notify members, or remove the pin when no longer needed.
Pin (or unpin) one message inside a chat. This is different from tg_pin, which pins the whole chat to the top of your dialog list.
| Name | Required | Description | Default |
|---|---|---|---|
| chat | Yes | ||
| unpin | No | ||
| notify | No | ||
| message_id | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already convey mutation (readOnlyHint=false), idempotency, and non-destructiveness. The description adds useful context about operating inside a chat and unpinning, but does not disclose side effects like whether notify controls a service message or whether pinning replaces an existing pinned message. No contradiction with 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?
Two sentences, no fluff. The core operation is front-loaded, and the differentiator from tg_pin is stated in a compact second sentence. Every word earns its place.
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?
The description is sufficient for choosing the tool and understanding its high-level behavior, and annotations cover safety traits. However, for actually invoking it correctly, important parameter semantics like unpin and notify are left to inference, and no guidance is given on what happens to previously pinned messages.
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 input schema has no descriptions for any parameter, so schema_description_coverage is very low. The description does not explain chat format, how message_id is used, or the semantics of unpin and notify. Parameter names and defaults provide only minimal clues, so the tool description fails to compensate for the schema gap.
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 begins with a clear, specific verb and resource: 'Pin (or unpin) one message inside a chat.' It also explicitly differentiates this tool from tg_pin by noting tg_pin pins the whole chat, making the tool's scope unmistakable.
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?
The description names the sibling tool tg_pin and gives the exact difference: message-level pinning here vs chat-level pinning there. This tells an agent when to choose this tool over the most likely alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.