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

The annotations already declare openWorldHint=true, readOnlyHint=false and idempotentHint=false, so the write/external nature is structured. The description still adds real value by warning that actual HTTP requests hit the customer's URL and that dry_run avoids sending — exactly the side-effect information an agent needs before acting.

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 sentences, front-loaded with what happens, followed immediately by the side-effect warning and the safe preview option. No filler or redundancy.

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 tool with no output schema, the description covers purpose, external side effects, and preview mode adequately. It stops short of describing what happens on delivery failure (error reporting, partial sends), which would matter when the endpoint is unreachable.

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 both webhook_id and dry_run are already documented in the schema. The description only echoes dry_run's meaning in prose, adding no syntax, format, or edge-case detail beyond the schema, 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?

The description states a concrete verb and resource: sending a sample payload for each event of a transactional webhook to its URL in order to verify delivery. The 'transactional' qualifier inherently separates it from the sibling test_webhook, but the description never explicitly routes an agent between the two, keeping it 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?

It gives a clear reason to call it ('to check that the endpoint receives them') and points at dry_run for a preview instead of a live send. It offers no explicit when-not guidance and never mentions the non-transactional test_webhook sibling as the alternative for regular webhooks.

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