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

Annotations already declare this is a non-read-only, non-destructive, closed-world mutation. The description adds genuine value beyond them by disclosing the Premium paywall and the concrete failure behavior (error plus plans-page link). It still omits what a successful call returns and whether access can be reverted by calling the tool again.

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 tight sentences: the action and its three outcome states come first, and the paywall caveat follows. Nothing is redundant and every clause carries information an agent needs.

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 two-parameter mutation with no output schema, the description covers action, ownership precondition, premium gating, and failure mode. The remaining gap is the success response shape and whether non-owned or invalid timeline_id produces a distinct error.

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 0%, so the description must carry parameter meaning; it partially does by glossing 'link' as 'visible by link only' and 'private', which map to the enum, but timeline_id is never described beyond the implied ownership. The enum values are self-explanatory, which limits the residual gap.

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 precise verb (make ... public/link/private), the resource (a timeline), and enumerates all three resulting states. No sibling tool touches access settings, so the definition is unambiguously distinct from create_timeline, copy_timeline, and the event tools.

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 the ownership precondition ('a timeline the user owns') and the premium gating condition that determines success or failure. It does not name alternatives, but no sibling offers a comparable capability, so there is little left to route between.

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