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

Beyond the annotations, the description reveals non-obvious server-side behavior: 'Nilyo recomputes authorized account_ids server-side.' This is valuable because it signals that account_ids may be adjusted automatically. The description also implies a mutating operation, consistent with readOnlyHint=false and idempotentHint=false.

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?

The description is two sentences with no filler, and the most important information—what can be updated—comes first. The workflow example and server-side behavior note each add distinct value.

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 complex 9-parameter mutating tool with no output schema, the description supplies a real workflow and a key server-side behavior note. It does not describe return values or update semantics (e.g., partial vs. full replacement), but the schema and parameter descriptions cover most invocation details.

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 description identifies the main update categories (URL, events, provider/account selection), and some parameters like events, providers, account_ids, and request_url already have schema descriptions. However, it does not add meaning for name, enabled, runtime, or auto_include_new_accounts, and schema coverage is only 56%, so the description only partially compensates for the gaps.

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 states exactly what the tool does: 'Update a webhook destination URL, events or provider/account selection.' It names a specific verb and resource and enumerates the modifiable aspects, making it easy to distinguish from webhook_create_destination, webhook_delete_destination, and webhook_get_destination.

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?

The description provides concrete usage context: 'Common n8n chain: create with Test URL -> receive mock event -> update same destination to Production URL.' This tells an agent when updating is appropriate in the lifecycle. It does not explicitly contrast with create/delete, but the workflow implication is clear.

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