mercury_update_webhook

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

Without annotations, the description fully covers behavioral traits: side effects (overwrites record, persistent, resume delivery if status flips to active, immediate effect of new URL). It also notes the same SSRF guard applies, and returns the updated webhook object. No contradiction with annotations as none exist.

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 extremely concise, using sections (USE WHEN, DO NOT USE, SIDE EFFECTS, RETURNS) to present information efficiently. Every sentence adds value, and there is no redundant or extraneous content.

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?

Given no output schema, the description specifies the return format explicitly. It covers preconditions (SSRF guard), side effects, and usage guidance. With 4 parameters (1 required) and no annotations, the description is sufficiently complete for an agent to use the tool correctly.

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%, but the description adds significant meaning: it explains the use of status for reactivation after failures, provides common eventTypes examples with a link to full list, and clarifies that the URL has the same rules as mercury_create_webhook. This goes well beyond the schema's basic descriptions.

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 starts with a clear verb+resource: 'Update an existing webhook endpoint', and specifies the updatable fields (URL, status, subscribed events). It distinguishes itself from siblings like mercury_create_webhook and mercury_delete_webhook by focusing on updating rather than creating or deleting.

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 explicit 'USE WHEN' and 'DO NOT USE' sections, stating when to use (rotating URL, changing events, reactivating auto-disabled webhooks) and when not (inspecting delivery history). It also references the SSRF guard from the sibling create tool, providing clear boundaries.

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