Join a Discord thread by providing its thread ID, enabling the bot to receive notifications and messages from that thread.
Have the bot join a thread to receive notifications and messages
| Name | Required | Description | Default |
|---|---|---|---|
| threadId | Yes | Thread Channel ID |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses the beneficial effect (notifications and messages) but says nothing about permission requirements, whether joining an archived thread works, or whether the call is idempotent if the bot is already a member.
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?
A single front-loaded sentence with no filler. It is efficient, though it stops short of the extra detail that would make it fully informative.
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 one-parameter membership action with no annotations and no output schema, the description covers the basic purpose and effect but omits prerequisites and edge cases (permissions, archived threads, already-joined behavior). Adequate but with clear gaps.
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 coverage is 100% with threadId documented as 'Thread Channel ID', so the structured data already explains the single parameter. The description adds no syntax or format detail beyond that, which makes 3 the appropriate baseline.
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 (join) and resource (thread) and adds the outcome (receives notifications and messages). It is clearly distinguishable from the obvious sibling leave_thread, though it does not explicitly name alternatives like create_thread or modify_thread.
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?
There is no when-to-use guidance, no prerequisites, and no alternatives named. The agent must infer that this is for joining an existing thread the bot is not yet a member of.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.