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

Annotations already declare readOnlyHint=true, so safety is covered; the description goes beyond them by disclosing that the webhook URL is redacted to its host because it embeds a delivery token, and that the full URL is only visible in the portal and CLI. With no output schema, that redaction notice is exactly the kind of behavioral context an agent needs to avoid reporting a truncated value as the real one.

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?

Three tight clauses with zero filler: what is returned first, then the redaction caveat, then the read-only restatement. The most decision-relevant information (scope and returned fields) is front-loaded.

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 read tool with no output schema, the description enumerates the returned fields, explains the one surprising output transformation (webhook redaction), and confirms the read-only nature. Nothing an agent needs to call it correctly or interpret the result 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?

Schema description coverage is 100% and the single parameter (destination_id) is fully documented in the schema, including where to obtain the UUID. The description adds no additional constraint, format, or failure-mode detail about the id, so the baseline 3 applies.

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?

Specific verb + singular resource ('Read one alert destination') with an explicit enumeration of the returned attributes: name, type, channel, description, template, enabled state. The singular scope cleanly separates it from the sibling list_alert_destinations, so an agent can pick the right tool without opening either schema.

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?

Usage is implied by the singular 'one' scope and the schema note that destination_id comes from list_alert_destinations, but the description states no explicit when-to-use or when-not-to-use condition and names no alternative (create_alert_destination, update_alert_destination, delete_alert_destination all sit nearby). Adequate but leaves routing to inference.

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