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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds significant behavioral detail: administrators receive complete bilingual records including drafts, while other accounts receive a single locale with specific fields and who are explicitly barred from event bodies and the timeline introduction/conclusion. This goes well beyond annotation hints.

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 description is two sentences with a front-loaded action. The second sentence is long and somewhat dense, but each clause carries necessary information about role-based responses. It is efficient enough for its content, though a bit more structured formatting could improve readability.

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?

Given the output schema and annotations, the description is largely complete. It covers what is returned for both admin and non-admin roles, mentions the canonical URL, and states exclusions. It does not cover error cases or pagination, but those are not critical for this read-only, single-resource tool.

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% and already documents both parameters thoroughly, including the locale's enum and note that it is ignored for admins. The description reiterates the locale guidance ('pass the caller's language in locale') without adding new semantic meaning, so the baseline 3 applies.

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 'Returns one published timeline', a specific verb+resource pairing that clearly states the tool's function. It distinguishes from sibling tools like get_news_by_id by focusing on timelines and immediately notes role-based response differences, making its scope 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?

The description gives clear usage context: use this tool to retrieve a timeline by ID, and instructs non-admin callers to pass their language in the locale parameter. It does not explicitly say when not to use it or name alternatives, but the context is sufficient for an agent to select it appropriately.

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