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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds non-obvious behavior: the signing secret is never returned, custom header values are masked as '[hidden]', headers are managed via dashboardUrl, results are newest-first, and starting_after/ending_before are mutually exclusive. These are genuine operational details beyond the annotations.

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-loads purpose and the routing guidance, with pagination details at the end. Slightly repetitive — 'newest first' appears in the opening sentence and again as 'sorted newest-first' — costing it the top score.

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 an output schema present and annotations covering the safety profile, the description supplies everything an agent needs: return-field highlights, masking behavior, sorting, and pagination rules. No gaps remain 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 description coverage is 100%, so the schema already documents event, status, limit, and the cursor params. The description mostly restates schema content (max limit 100/default 10, cursor mutual exclusivity) rather than adding new meaning, so the baseline 3 applies.

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 (List) and resource (webhook endpoints) scoped to 'this Checkout Page account', and describes the returned fields (subscribed events, status, delivery counters). An agent can distinguish it immediately from get_webhook, create_webhook, and the other list_* siblings.

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?

Explicitly names when to use it: to find an id for get_webhook/delete_webhook and to check whether a URL is already registered before create_webhook. This routes the agent to sibling tools and states the triggering conditions, leaving nothing to inference.

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