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

Annotations declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true), so the bar is lower. The description adds genuine context beyond them: the alert is REAL, not a dry run, and it exists to verify external delivery — exactly the kind of side-effect disclosure annotations cannot express.

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 short sentences, front-loaded with the action and ending with the call syntax. The middle sentence is justification rather than instruction but it earns its place by explaining why the tool must be used.

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 two-parameter, non-destructive action with annotations and no output schema, the description covers purpose, timing, and invocation. Return-value details are not required given no output schema, though it could say what the agent should report back after a test.

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 schema already documents both parameters, including the enum and the conditional webhook_id requirement. The description's 'Pass channel=... with a webhook_id' merely restates what the schema encodes, so 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?

States a specific verb and resource ('Fire a real test alert') plus its purpose ('so the user can confirm delivery works'). This clearly distinguishes it from the configuration siblings set_email_alerts and add_webhook_alert, which set up channels rather than exercise them.

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?

Gives explicit, strongly-worded timing guidance ('ALWAYS finish a monitoring setup with this') and explains the failure mode it prevents. It does not name a when-not condition or an alternative tool, so it falls just short of the top band.

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