Post a new message to a Mattermost channel using the channel ID and message text.
Post a new message to a Mattermost channel
| Name | Required | Description | Default |
|---|---|---|---|
| message | Yes | The message text to post | |
| channel_id | Yes | The ID of the channel to post to |
Changes observed during successful MCP inspections.
v1.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description bears full responsibility but only states the obvious. It does not disclose write behavior specifics, potential errors, permissions, or side effects.
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, direct sentence that efficiently states the tool's purpose. No unnecessary words or redundancy.
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?
Despite the tool's simplicity, the description omits important context such as return value (e.g., message ID), error handling, or any side effects. Given no output schema or annotations, more completeness is expected.
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%, and the description adds no extra meaning beyond what the schema already provides for channel_id and message. Baseline score of 3 is appropriate.
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 clearly states the action ('post a new message') and the target resource ('Mattermost channel'). It implicitly distinguishes from siblings like 'reply_to_thread' by specifying 'new message', but lacks explicit differentiation.
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?
No guidance is provided on when to use this tool versus alternatives like mattermost_reply_to_thread. There is no mention of prerequisites, limitations, or context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.