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

Annotations only cover safety flags (readOnlyHint=false, destructiveHint=false, openWorldHint=true), while the description supplies the behavior that actually matters: roughly one-minute delivery latency, the exact JSON envelope POSTed, the HMAC signature formula and header names, and the one-time secret disclosure. The 'secret is returned only now: store it' warning is a genuine operational constraint no annotation conveys.

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?

Front-loaded with the outcome, then progressively more technical detail (payload, then signature, then secret, then removal) in four tight sentences with no filler. The marketing tone of the opening clause is the only expendable flourish.

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?

An output schema exists, yet the description still flags the single most important return detail — the secret is sent once — and covers payload format, verification, latency, and teardown. For a two-parameter tool with open-world side effects, an agent has everything needed to call it and to handle the response correctly.

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?

With 0% schema description coverage the description must carry parameter meaning, and it does for the non-obvious one: url must be a public HTTPS endpoint, and the empty-string sentinel means removal. api_key is left entirely unexplained, though its role as the credential is conventional enough that this is a minor gap.

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 makes clear this configures an inbox push webhook: it states that new items are POSTed to the given public HTTPS URL and that url="" removes the webhook. The verb framing is narrative ('Get your inbox PUSHED instead of polling') rather than a crisp 'register a webhook', and it never names a sibling, but the resource and effect are unmistakable.

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 explicitly positions the tool against the polling alternative ('instead of polling'), which is the key decision an agent faces, and documents the removal case via an empty url. What it lacks is a pointer to the concrete polling sibling (my_inbox) for agents that cannot host a public endpoint.

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