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

Annotations already establish readOnly/idempotent/non-destructive/closed-world, so the bar is lower; the description still adds real value by disclosing that the signing secret is never returned and that the address is masked, plus the caller authorization scope. 'Reading changes nothing' largely restates readOnlyHint=true but harmlessly reinforces it.

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?

Three short sentences, front-loaded with the action and its returned fields, followed by security constraints. Every sentence is close to earning its place, with 'Reading changes nothing' the only near-redundancy against the annotations.

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 tool with an output schema, this covers the things an agent cannot infer: secret redaction, address masking, and caller authorization. Nothing essential is missing, though error behavior for an unknown id is unspecified.

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 'id' parameter is fully documented in the schema as the webhook endpoint's id, so the description adds no syntax or format detail beyond it. Baseline 3 applies when the schema carries this load.

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 opens with a specific verb+resource ('Read one webhook endpoint') and enumerates what is returned (masked address, status, events). The word 'one' implicitly separates it from list_webhook_endpoints, though no sibling is named explicitly.

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 'Read one webhook endpoint' plus the access restriction ('Only the account owner's API keys and connected apps can read webhooks'), which tells the agent whether a call is even permissible. There is no explicit when-not guidance or named alternative for listing vs. single retrieval.

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