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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the description is not carrying the safety burden alone. It nonetheless adds real behavior beyond them: addresses are redacted to host plus masked path, signing secrets are never returned, and access is restricted to the account owner's keys and connected apps. 'Reading changes nothing' is redundant with readOnlyHint but harmless reinforcement.

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?

Four short sentences, front-loaded with the core action and ordering before the redaction and auth caveats. Each sentence carries distinct information except 'Reading changes nothing', which restates the readOnlyHint annotation and could be dropped.

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 zero-parameter read tool with an output schema and full annotation coverage, the description supplies everything an agent needs: what is listed, the order, what is redacted, and who may call it. Return-value shape is covered by the output schema, so nothing material 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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter meaning left to convey. The description correctly spends its words on return-value behavior instead of inventing parameter guidance.

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 the account's webhook endpoints') plus the fields returned ('status and events') and the ordering ('oldest first'). It does not explicitly distinguish itself from siblings like get_webhook_endpoint or list_webhook_deliveries, though the singular/plural naming makes the split largely inferable.

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 'List the account's webhook endpoints' — an agent knows this is the enumerate-everything call — but there is no explicit when-to-use versus get_webhook_endpoint or list_webhook_deliveries. The auth sentence ('Only the account owner's API keys and connected apps can read webhooks') is a useful eligibility gate but is not framed as a routing rule.

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