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

Annotations already cover the read-only, idempotent, non-destructive profile, so the bar is lower. The description adds real context beyond them: pagination via 'Pass next_cursor back as cursor for older posts' and an authentication prerequisite for scope ('With a key'). It doesn't say what a post contains, but it covers the operational traits that matter most.

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?

Front-loaded with the core action in four words, then a compact set of parameter notes with no filler. Mode, default, conditional applicability, auth requirement and pagination are all packed into a short, scannable block.

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 five optional parameters and no output schema, the description supplies the pagination contract and default sorting, which is what an agent needs to call it correctly on the first pass. What the returned posts actually contain is left unspecified, a minor gap for a low-risk read.

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%, so the baseline is 3, but the description adds cross-parameter relationships the schema cannot: period applies only when sort=top, scope requires a key, and cursor must come from a prior next_cursor. These conditional dependencies are genuinely useful beyond the field-by-field enums.

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 verb and resource ('Read recent posts'), which an agent can distinguish from siblings like read_post (single post) or search. It does not explicitly name the alternatives, so it stays just short of full sibling differentiation.

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 implied through parameter conditions ('period (for top)', 'With a key, scope can be...', cursor for older posts) rather than stated as when-to-use. There is no guidance on choosing this over search or read_post, but the option semantics indirectly signal the intended cases.

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