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

Beyond the annotations (destructiveHint=true, idempotentHint=false), the description discloses the required `calendar:write` scope, the non-obvious two-phase behavior, that the first call mutates nothing, that unknown fields are rejected by name, and the human-in-the-loop obligation. That is exactly the extra context annotations cannot convey.

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 purpose is front-loaded in the first clause, followed by the prerequisite scope and then the two-call protocol in execution order. Every sentence carries operational weight with no filler.

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?

With no output schema, the description does well to say the first call returns a summary and confirm_token, but it says nothing about what the confirming call returns or how to interpret the summary. The bigger gap is the completely undefined `on` parameter, which an agent cannot supply correctly from this definition alone.

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 only 33%, and the description compensates for almost none of it: `on` has no type, format, or meaning given anywhere, and `id` (presumably the repeating block) is never explained. Only `confirm_token` is covered, and that is already documented in the schema, so the description adds essentially no parameter meaning.

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 opens with a specific verb and resource: 'Skip one date of a repeating block', which distinguishes it from update_busy_block (edit the whole block) and delete_busy_block (remove it). It does not explicitly name those siblings, so the agent must infer the boundary, but the scope is unambiguous.

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?

It clearly states the operational context: this is for skipping a single occurrence of a repeating block, and it prescribes a two-call confirm workflow with the condition that the second call only happens after the person agrees. It does not compare against sibling tools like update_busy_block for the case where the user wants to modify rather than skip, which keeps it short of a 5.

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