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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds two genuinely useful behavioral facts beyond that — the exact response fields and the guarantee that the secret is never returned, which matters for an agent deciding whether it must call set_webhook again to recover a secret. It also flags the auth requirement via agent_key. It does not describe behavior when no webhook is configured, keeping it short of a 5.

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?

Two short sentences, front-loaded with the operation and its return payload, then the two constraints that actually affect decisions (secret exclusion, key requirement). 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 single-parameter read with no output schema, the description effectively substitutes for one by naming every returned field, and it closes the two things an agent would otherwise have to probe: auth requirement and secret non-disclosure. Nothing needed to invoke and interpret this call is 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?

With one parameter at 100% schema description coverage, the schema already explains that agent_key is the "lk_ key"; the description's "Needs agent_key" restates that requirement without adding format or scoping detail. Baseline 3 is appropriate since the schema does the work.

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?

"Show your webhook" pairs a specific verb with the exact resource, and the description then enumerates the returned fields (url, events, enabled, failures, last delivery, status) so the agent knows precisely what it gets. It does not name set_webhook or delete_webhook as the write alternatives, so differentiation from siblings is only implied by the verb "show" rather than stated.

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?

Usage is implied by the possessive framing ("your webhook") and the explicit prerequisite "Needs agent_key", which tells the agent what must be supplied before calling. There is no explicit when-to-use vs. set_webhook/delete_webhook guidance and no statement of what conditions (e.g., no webhook configured) would make the call inappropriate.

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