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

Annotations already declare readOnly/non-destructive/closed-world, so the bar is lower. The description adds genuinely new context — 'Works without sign-in' (auth requirements) and that matching is by title — which annotations do not cover.

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?

Three short sentences, front-loaded with the core action, with no filler. Each sentence contributes something (what, auth, when).

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 simple read-only, no-output-schema tool, the description covers purpose, auth, and a usage trigger. The notable gap is the undocumented limit/pagination, but safety and scope needs are met.

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 compensate. 'By title' usefully clarifies that the required query matches titles, but the limit parameter (default 10, max 50, pagination behavior) is left entirely undocumented in both schema and description.

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?

Uses a specific verb (Search) and resource (public timelines on Time.Graphics), and narrows scope to matching by title. 'Public' implicitly distinguishes it from list_my_timelines, but no sibling is named explicitly.

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?

'A good start before creating a new one' gives one clear usage scenario (dedupe check before create_timeline). However, it never states when NOT to use it or contrasts it with list_my_timelines for private timelines, leaving the main routing decision to inference.

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