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

With no annotations, the description carries the full burden and does disclose useful behavior: return ordering (oldest first), default window (today to horizon), echoing back param values, and the month-precision matching semantics. It omits what happens when nothing is scheduled, rate limits, or auth, so it's solid but incomplete.

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 sentences, front-loaded with the resource and examples, then the usage and return semantics. It's a bit dense, packing several clauses into sentence two, but every element earns its place.

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 two optional parameters, no output schema, and no annotations, the description is nearly complete: it covers purpose, usage, ordering, default scope, and precision edge cases. Minor gaps (empty-result behavior, pagination) keep it from a 5.

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 already 100%, so the baseline is 3. The description adds meaning beyond the schema by explaining that month-only dates carry precision=month and are matched on the month, and by framing 'today to the horizon' semantics — value the schema doesn't provide.

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 states a specific resource ('scheduled dates the timelines are watching') with concrete examples (earnings, rulings, launches, rule deadlines) and contrasts its cross-site scope against reading individual timelines. That cross-cutting scope cleanly distinguishes it from siblings like get_timeline and list_timelines.

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 gives a clear when-to-use ('to answer what happens next across the site, rather than reading each timeline for its own catalysts'), which implicitly routes the agent away from per-timeline tools. However, it doesn't name a specific sibling alternative or state any explicit exclusion, so it falls short of the 5 bar.

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