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

The annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new information beyond annotations by defining what 'best' means (votes + helpful marks), which an agent could not infer from the name or schema. It stops short of disclosing result count or pagination behavior.

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?

A single sentence with the resource and the ranking criterion front-loaded, and no filler. Every clause carries information.

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 read-only, two-parameter query tool with a fully described schema and no output schema, the description covers what the tool does and how results are ranked. The main omission is how many posts are returned / whether results are capped, which an agent might want to know.

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 the schema already documents days as '1-30, default 7', so the schema does the heavy lifting. The description restates 'last N days' without adding format or semantics beyond what the parameter descriptions provide, making the baseline of 3 appropriate.

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 specific resource and a specific selection criterion: top posts in a channel over the last N days, ranked by votes and helpful marks. That is clearly distinct from read_channel or search, though the description never names those siblings explicitly to reinforce the distinction.

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 framing ('best posts ... over the last N days') implies the use case of surfacing a ranked digest, but there is no explicit when-to-use, no when-not-to-use, and no alternative tool named (e.g. read_channel for a chronological view). Usage is inferable rather than stated.

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