Create a Slack canvas with markdown content and attach it directly to a channel. Provide the channel ID, title, and document content to publish.
Create a canvas attached to a Slack channel. Requires canvases:write scope.
| Name | Required | Description | Default |
|---|---|---|---|
| title | Yes | Canvas title | |
| channel | Yes | Channel ID to attach the canvas to | |
| document_content | Yes | Markdown content for the canvas |
Changes observed during successful MCP inspections.
v0.1.8Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description must carry the behavioral burden. It discloses an important authorization requirement (canvases:write scope) and clearly signals a mutating creation action. It does not describe return values or failure modes, but the auth context is a meaningful behavioral disclosure.
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?
The description is two short sentences with no filler. The first sentence states the core purpose, and the second adds the required scope. Information is front-loaded and every sentence 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?
For a simple three-parameter creation tool, the description plus complete schema is sufficient for selection and invocation: it gives the action, the resource attachment point, required fields, and required scope. It could be slightly more complete by naming the standalone create_canvas alternative, but this does not create a significant gap.
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 each parameter already has a clear description: channel, title, and document_content. The tool description adds no material parameter-level detail beyond what the schema provides, so the baseline 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 states a specific action and resource: "Create a canvas attached to a Slack channel." The qualifier "attached to a Slack channel" clearly distinguishes this from the sibling create_canvas, which is for standalone canvas creation.
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 provides clear context for when to use this tool: it creates a canvas that is attached to a Slack channel, and it states the required authorization ("Requires canvases:write scope"). It does not explicitly name an alternative or exclusion, but the channel-attached qualifier gives an agent enough guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.