Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish that this is a write operation and non-destructive. The description adds useful behavioral nuance beyond the schema: enabling or configuring a channel does not activate event notifications, which is a non-obvious consequence. It does not cover overwrite behavior or validation, but the most important behavioral caveat is disclosed.

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 short, focused sentences with no wasted words. The core action is front-loaded, and the critical caveat about per-event preferences is placed at the end where it is easy to retain.

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 3-parameter tool with complete schema coverage, useful annotations, and an output schema, the description covers the purpose, the main behavioral caveat, and the correct sibling tool. Nothing necessary for correct invocation is missing.

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 schema already documents all three parameters, so the baseline is 3. The description adds meaning by clarifying the enabled parameter's semantics: enabling a channel does not turn on events for anything. It also reinforces that webhook_url is the incoming-webhook URL, adding enough beyond the schema to warrant a higher score.

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 uses a specific verb and resource: 'Configure a Slack or Discord notification channel' with an incoming-webhook URL. It also distinguishes itself from related notification tools by clarifying that enabling a channel is not the same as enabling event notifications, which prevents conflation with update_notification_preferences.

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 explicitly tells the agent when this tool is appropriate and points to the correct alternative for per-event notification settings: 'set that per event via update_notification_preferences.' This is clear, actionable usage guidance and prevents a common misuse.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.