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

Annotations only tell us it is a non-destructive, idempotent write; the description goes much further, spelling out downstream effects per visibility (feed presence, airing, predictions/points, character memory and public record) and the irreversibility of airing. It also discloses the return shape { episode_id, visibility, now, note }, which 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?

Front-loads the action and cost ('Free. Change who can see...'), then organizes effects by visibility. The per-visibility blocks are dense run-ons with repeated phrasing ('out of the public record and character memory'), which costs some readability but each clause carries distinct behavioral information.

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?

For a three-parameter mutation with no output schema, the description covers ownership prerequisites, per-value side effects, reversibility limits, and the exact return fields. Nothing needed to invoke it correctly is missing.

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?

With 100% schema coverage the baseline would be 3, but the description adds real meaning beyond the enum's terse 'Who can see the date' by explaining the consequences of each value. An agent can pick public/unlisted/private from the description alone without reasoning about side effects.

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+resource ('Change who can see a date you booked') and immediately scopes ownership with '(you're its host)'. No sibling tool performs visibility changes, so differentiation is inherent and 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?

Gives clear context for each of the three visibility values and the host precondition, plus the reversal rule ('A private date can go public or unlisted again later; once aired, a date stays aired'). It doesn't name an alternative tool, but none of the siblings compete for this operation.

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