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

Discloses important side effects and operational behavior beyond annotations: 'SIDE EFFECTS: contacts external destination URLs you configured; may retry on failure,' the pay-per-success billing model, dedupe by delivery id, and fail-closed on billing/ceiling errors. This is detailed and honest about external calls, retries, and charging, which an AI agent needs before invoking a side-effecting webhook relay.

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?

Every sentence carries distinct information: purpose, billing, side effects, usage context, and input requirements. It is front-loaded with the main verb and resource, and it avoids filler or redundant restatement of the tool name.

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?

The description covers what the tool does, when to prefer it, side effects, retry behavior, billing, deduplication, and fail-closed behavior. Combined with the detailed input schema, an agent has enough context to select and invoke the tool correctly without guessing about external consequences.

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 high (id and deliveryId both documented), so the baseline is 3. The description adds genuine value by saying the upstream JSON body is an input and clarifying that 'id' is the endpoint id, plus framing deliveryId's dedupe behavior. It doesn't independently document parameters but reinforces the core calling convention.

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 opens with a specific verb and resource ('Relay a third-party webhook into CallMeter') and unpacks the exact pipeline: verify HMAC/shared secret, dedupe by delivery id, store payload, forward to destinations with retries. This clearly distinguishes it from the sibling tools, especially since the 'relay' action of receiving callbacks is distinct from replaying or extracting.

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?

Provides an explicit usage directive: 'Prefer when an agent must accept provider callbacks without running its own queue.' This tells the agent when to choose the tool, but it does not explicitly say when not to use it or name an alternative tool for resending/retrying events. Still, the use case is clear and specific.

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