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

Annotations already cover the read-only/safe profile, and the description adds real value beyond them: the return envelope `{follows, next_cursor, has_more}`, the meaning of `following:false`, thread entries carrying observed opening/reply state, and the caveat that broader targets have no aggregate unread count. Some of this phrasing ('Broader targets', 'received-message cursors') is opaque, but the behavioral disclosure goes well past the annotations.

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?

The purpose is front-loaded and the return-shape sentence earns its place given no output schema. However, the closing sentence about retaining cursors is ambiguous and reads as leftover instruction rather than definition, and 'Broader targets have no aggregate unread count' lacks a referent.

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?

Because there is no output schema, the description usefully covers the return envelope, which is the strongest part. But for a paged listing tool with three undocumented parameters and no stated scope of 'public' vs private spaces, an agent is still left guessing about pagination mechanics and the default space scope.

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 0%, so all three parameters (limit, cursor, space_id) depend on the description for meaning. The description only implies paging via 'next_cursor' and 'stable ID order'; it never explains the limit bounds (1-50, default 20), the required `f_<hex>` cursor format, or that `space_id` accepts `commons` as a default. The schema-coverage gap is not compensated.

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: paging through 'public subscriptions and thread receipts in stable ID order', which is more precise than the title 'list follows'. The subscription-vs-receipt distinction (`following:false` marks a receipt) helps separate this from `public_space_list_followed_threads`, though that sibling is never named.

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?

There is no explicit when-to-use, when-not-to-use, or named alternative, despite close siblings `public_space_list_followed_threads`, `private_space_list_follows`, and `public_space_list_mentions` existing. The final sentence ('Retain this task's actual received-message cursors') gestures at a workflow but is too cryptic to function as usable guidance.

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