List accessible channels in the connected Slack workspace.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "slack_list_channels"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| types | No | Channel types to list (e.g. "public_channel,private_channel"). | public_channel |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full behavioral burden and mostly does not meet it. It does not say whether results are paginated, whether private channels are omitted by default, what the return shape is, or what happens if the workspace connection lacks scopes — all of which matter for a read against a permissioned external service.
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 or redundancy. It is efficient but borders on under-specified rather than deliberately terse.
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 tool is structurally simple (one optional param, no output schema), which lowers the bar, but with zero annotations the description should still cover pagination and result limits. Instead it supplies only the resource name, leaving the agent without enough detail to call it correctly in a large workspace.
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 baseline is 3: the schema already explains the types parameter and its default. The description adds nothing beyond that, notably failing to mention that private channels require changing types, which would be the one piece of extra meaning worth contributing.
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 and resource ("List accessible channels") plus the scope (the connected Slack workspace), which is enough for an agent to know exactly what it retrieves. It does not name or contrast with any sibling tool, so it falls short of a 5.
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 mention of when not to use it, and no pointer to any alternative such as slack_post_message_draft. The word "accessible" hints at a permission boundary but is never explained, leaving the agent to infer whether it must filter first.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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