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

With no annotations, the description carries the burden and does well: it discloses HMAC signing, 5 retries over 7 hours, an event log with replay, a per-event price of €0.0005, and that billing is charged to the key in the Authorization: Bearer header. It stops short of stating whether delete is irreversible or whether the event log is retained after deletion.

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?

Capability, behavior, cost, and auth are front-loaded in one dense sentence before the parameter list, so the most important context appears first. The trailing 'Parameters —' block is a compressed run-on that packs eight definitions into one line, which is efficient but harder to scan.

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 an eight-parameter, multi-operation tool with no annotations, the description covers the mode selector, the safety/behavior profile (signing, retries, log, replay), cost, and authentication. Since an output schema exists, it need not explain return values, leaving nothing essential for correct invocation 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 0%, so the description must define all eight parameters, and it does: op values, target, name, every_minutes range, method values, body, id, and event_id. The compensation is solid though slightly terse where 'id: hook id' and 'event_id: event to replay' could be confused, and every_minutes is described as a range while the schema types it as a string.

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 first sentence states a concrete verb and resource: it issues an inbound URL that accepts webhooks and forwards them to a target, or schedules a call to a URL. It also names distinct mechanisms (HMAC signing, retries, event log, replay) that no sibling tool offers, so an agent can tell it apart from change_monitor or cron_explain without opening the 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?

The 'op' enumeration effectively tells the agent which mode to pick for each job: create for relay, schedule for periodic calls, list/events/replay/delete for management. It does not state when NOT to use this tool or what happens if op is omitted beyond '(default)', but the operation menu supplies clear routing.

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