mailkite_verify_webhook

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

Annotations only provide readOnlyHint=true, yet the description goes far beyond: it discloses the exact algorithm (HMAC-SHA256 over `${t}.${payload}`), the no-network execution, the no-credential requirement, and the return semantics (true only when signature matches and event is within freshness window). This is rich behavioral disclosure consistent with the readOnlyHint — no contradiction.

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?

The description is front-loaded with the purpose, but it redundantly repeats the local/no-network point twice: 'Runs entirely locally (HMAC-SHA256...) — no network call' and later 'Runs locally (no API call) — no credentials needed.' This repetition of the same claim adds noise without new information.

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 verification tool with no output schema, the description conveys the return semantics (returns true only on match + freshness) and the full algorithm, which is sufficient for correct calling. The toleranceMs default and disable behavior are covered in the schema. Only minor gaps exist, such as not explicitly stating the false return path, which is implied.

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%, so the schema already documents all four parameters well. The description adds modest value by explaining how payload and signature combine in the HMAC computation and reinforcing toleranceMs's replay-blocking role, but it doesn't add much beyond what the schema already conveys. Baseline 3 is appropriate.

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 specific verb (Verify) and resource (the x-mailkite-signature header on an inbound webhook delivery). It clearly distinguishes itself from the ~13 webhook-related siblings (set_webhook, test_webhook, delete_webhook) by focusing on signature verification rather than webhook configuration. An agent can tell this apart from siblings 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 description establishes strong usage context by emphasizing it runs entirely locally with no network call and no credentials needed, which differentiates it from the API-calling siblings. It also references the freshness window for replay protection. However, it doesn't name specific alternatives or explicit when-not-to-use conditions, leaving some inference to the agent.

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