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

Annotations already declare read-only, idempotent, closed-world behavior, so the description's added value is the status model (estimated vs confirmed) and the disclosure that each confirmed entry carries its source. The plan-tier reference is valuable behavioral context about who announces or supplies the data, though it is phrased so vaguely that an agent cannot tell whether a lower-tier caller gets errors or partial data.

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?

It is a single dense sentence that front-loads the resource ('Across countries: holidays whose date depends on an announcement'), which is good. However, the trailing parenthetical about plans is syntactically tangled and the parenthetical stack (Eid, Mawlid, status, source, plans) makes it harder to parse than necessary.

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?

With no output schema, the description carries the burden of describing return values; it partially does so via status and source, but leaves the actual shape (holiday name, date, country, confidence fields) unspecified. For a simple two-parameter read tool this is adequate but not fully complete.

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 100%, with both parameters documented including format examples ('KE,NG,MA') and the default of 14. The description reinforces the look-back/look-ahead window, but adds no meaning beyond the schema for the parameters themselves, 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 names a specific resource (announcement-dependent holidays such as Eid, Mawlid, moon-sighted and ad-hoc days off) and a specific window (a week back to N days ahead). It implicitly contrasts with get_public_holidays by scoping to announcement-dependent dates, but never names that sibling, so differentiation requires inference from the title.

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?

Usage is only implied: an agent can deduce this is for uncertain/announcement-driven holidays, but there is no explicit 'use this instead of get_public_holidays when...' routing. No exclusions or prerequisites are given, and the plan-tier mention ('Developer, Pro and Compliance plans') is ambiguous about whether it gates access or merely labels the announcer.

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