mercury_update_webhook

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

The description discloses side effects: overwrites the webhook record, persistent changes, immediate effect of new URL, and resumption of delivery if status becomes active. This adds detail beyond the annotations (destructiveHint=false, openWorldHint=true), which only hint at safety and side effects.

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 concise, using structured labels (USE WHEN, DO NOT USE, SIDE EFFECTS, RETURNS) to organize information efficiently. No superfluous sentences; each section adds clear 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?

Despite no output schema, the description explicitly states the return format as '{ id, url, status, events, ... }'. It covers all relevant aspects for an agent to use the tool correctly: when to use, side effects, parameter semantics, and return values.

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?

All parameters have descriptions in the schema (100% coverage), and the description adds value by providing concrete examples for eventTypes, clarifying status effects (reactivation), and reiterating security rules for url. This goes beyond the schema's basic type/format info.

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 explicitly states 'Update an existing webhook endpoint (URL, status, or subscribed events)', using a clear verb+resource structure. It distinguishes itself from sibling tools like mercury_create_webhook and mercury_delete_webhook by focusing on updates.

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 includes 'USE WHEN' and 'DO NOT USE' sections, providing explicit guidance on appropriate contexts (e.g., rotating URL, reactivating after failures) and exclusions (e.g., inspecting delivery history). It also references sibling behavior for SSRF guard.

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