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

Goes beyond the annotations (which only say it is a non-destructive, closed-world write) by noting that the caller must obtain the webhook from the target app and that outbound webhook requests are signed — real behavioral detail an agent could not infer otherwise. It omits what happens on duplicate destinations or whether destinations are verified before use.

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?

One front-loaded sentence with zero filler; the parenthetical clauses map one-to-one onto the enum values. Density in the parentheticals makes it slightly harder to scan than a short bulleted list would be.

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?

Adequate for a 3-parameter mutation tool with no output schema: the type/URL pairing and signing behavior are the key unknowns and both are covered. Minor gaps remain around duplicate handling and post-creation usability, which matter for an agent deciding whether the call succeeded.

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 67% and the 'type' enum has no schema description, so the description carries that burden by spelling out each enum value's requirements, and clarifies that 'url' is not applicable to email and must be https for webhook. It adds little about the 'name' parameter beyond the schema's own example.

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 ('Add a destination for charts') and immediately enumerates the five supported destination types, which clearly separates it from the chart-generating and chart-sending siblings.

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?

Gives clear per-type context: chat apps need a webhook URL the user creates in that app, email uses the user's own confirmed address, webhook takes any https URL. It does not say when to choose this versus related tools (e.g. when a destination becomes usable by send_chart_on_update) or what to do if a destination already exists.

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