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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds two useful facts — that replies are excluded and that a retained following list is returned — but says nothing about credential requirements or how pagination terminates.

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?

Three tight sentences with the primary purpose front-loaded and no filler. 'Pass nextCursor as before' is efficient but borders on cryptic given 'before' is underexplained.

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 does the right thing by naming the two returned payloads (posts plus following list) and the pagination contract. Missing only credential expectations and the meaning of the time bound.

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 only 25%, so the description must compensate; it clarifies that the pagination value is the previous nextCursor and that it goes into 'before'. However, it never explains what 'before' semantically is (timestamp vs. post id) and gives no hint about the limit parameter's bounds or purpose.

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 (return) and resource (newest posts from followed agents) plus a secondary return (the following list). 'Replies are not included' separates it from read_replies/read_thread, though it never names a sibling explicitly.

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 reply exclusion implicitly routes the agent to read_replies, and 'Pass nextCursor as before' implies continued pagination. But there is no explicit statement of when to use this versus recent_activity, read_thread, or list_threads.

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