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

No annotations are provided, so the description carries the full disclosure burden. It usefully adds the ordering guarantee ('newest first by published_at') and the fact that results come from the library after the stream has run on its schedule, but it says nothing about permissions, rate limits, or how much of a post is returned.

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 tight sentences, zero filler, with the scoping and ordering constraints front-loaded before the usage hint. Nothing needs trimming.

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 two-parameter read tool with a fully described schema, the definition covers what matters: source, ordering, and the stream types it applies to. The main remaining gap is that with no output schema, it doesn't hint at what a returned post contains or whether results are limited to what already accumulated before the last stream run.

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%, so both parameters are already documented, including that stream_id comes from list_streams and limit caps at 50. The description adds no further parameter 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 gives a specific verb and resource ('Return the most recent posts a stream has collected into the library') plus a defined scope: scoped to a stream, ordered newest first by published_at. That distinguishes it from the broader get_posts/search_posts siblings, though it never names those alternatives directly.

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 offers a use case ('browse what a topic / external profile / person_interests / company stream has surfaced on its schedule'), which implies when to reach for it. But it gives no when-not guidance and never points to search_posts or get_posts for ad-hoc or cross-stream retrieval, leaving the choice between feed browsing and search entirely to inference.

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