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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, so the safety profile is covered structurally. The description adds genuinely non-obvious behavioral context: clearing the occurrence prompt does not cause a fallback to anything, because the series prompt was already in effect, plus the recordings:write authorization requirement. It stops short of saying whether clearing a non-existent prompt errors or how to restore 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?

Two sentences, front-loaded with the action, second sentence devoted entirely to the one non-obvious semantic point (no fallback) and the scope requirement. No filler and nothing repeated from the schema.

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?

Clear and complete for a deterministic operation whose three parameters are fully documented in the schema and whose safety profile is in annotations. The one thing an agent could get wrong here — assuming the series prompt disappears too — is explicitly addressed.

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 description coverage is 100%, with account, eventId, and workspace all documented in the schema itself (including the eventId pointer to hub_list_calendar_events). The description adds nothing about parameter formats, so the baseline 3 applies rather than a higher score.

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 ('Remove') and a precise resource ('one occurrence's own prompt'), and implicitly separates it from the series-level siblings by noting the series prompt is untouched. It never names the sibling tools (hub_clear_series_custom_prompt, hub_clear_call_custom_prompt) explicitly, and 'occurrence' is never mapped back to 'event', so the tool name has to do some work.

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 clarifies the outcome of clearing (series prompt continues to apply) which implies the use case: removing a per-occurrence override only. However, it gives no explicit guidance on when to choose this over hub_clear_series_custom_prompt or hub_clear_call_custom_prompt, and no note on prerequisites beyond the scope requirement.

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