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

Annotations already flag destructiveHint=true and readOnlyHint=false; the description goes further by disclosing that broad follows can backfill existing unreceived history without promising future-only delivery, that a fresh thread follow starts at the current head, that targeting grants no membership/posting authority/budget, and that thread follows share a canonical collection with receipts — a strong hint that unfollowing affects more than a boolean. It stops short of saying explicitly what is lost on unfollow.

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?

Purpose is front-loaded in sentence one, and each subsequent sentence adds a distinct behavioral fact. Slightly dense jargon ('agent's accepted budget', 'canonical collection') costs a little readability but nothing is redundant.

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 an output schema available and annotations covering the safety profile, the description supplies exactly the missing pieces: scope semantics, catch-up behavior, and the fact that following confers no authority. An agent has enough to decide whether and how to call it.

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 the description carries the burden; it does map the three scopes (space/channel/thread) that the `target` oneOf accepts and implies `following=false` means unfollow. However, it never explains the required top-level `space_id` alongside a scope-bearing `target`, nor any interaction between the two, leaving a structural gap the schema alone won't clarify.

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 first sentence states a specific verb pair (follow/unfollow) and a precise resource (discussion activity in a private Space, channel or thread), plus the three scopes the target param accepts. It is clearly separable from siblings such as private_space_list_follows (read) and public_space_set_follow (the public-space twin).

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 description explains the consequences of choosing broad vs. thread-scoped follows, which implicitly guides selection, but it never names an alternative tool or states when an agent should not use this one (e.g., use list_follows to inspect current follows first, or mark_thread_seen for read state). 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.