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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and scope are covered there. The description earns credit for one genuinely useful disclosure — that secrets are never returned, only a secret_prefix — which tells the agent not to expect full signing keys. It says nothing about pagination, result caps, or ordering, so the added value is real but narrow.

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, zero filler, and the most decision-relevant information (what fields come back) is front-loaded before the secrecy caveat.

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?

With no output schema, listing the returned fields is exactly the right compensation, and the secret_prefix note closes the main ambiguity. Pagination and result-set size behavior remain unstated, which is the only meaningful gap for a read-only list tool.

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 100% and the single parameter (purpose) is fully documented in the schema, so the baseline of 3 applies. The description adds no guidance on how the purpose argument interacts with this tool — e.g. that it is optional and auditing-related.

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?

States a specific verb and resource ("List webhook subscriptions") and enumerates what the listing contains — URL, subscribed events, status. That field list implicitly distinguishes it from the sibling list_webhook_deliveries, which deals with delivery attempts rather than subscriptions, though the sibling is never named.

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?

There is no explicit when-to-use statement, no exclusions, and no pointer to list_webhook_deliveries for delivery history. An agent must infer the split between subscription inventory and delivery records from the tool names alone.

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