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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful context: return shape ({mentions: {items, next_cursor, has_more}}), ordering, and the instruction to keep mention cursors separate from thread reply cursors. It stops short of pagination limits or rate behavior.

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 with no filler, and the ordering plus return-shape facts are front-loaded before the cursor-retention caveat.

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?

It compensates for the missing output schema by describing the return shape and cursor semantics, but with 0% schema coverage across three parameters, the description leaves limit and space_id unaddressed, so it is not fully complete for invocation.

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 must carry the burden, but it only illuminates the cursor concept. It says nothing about limit (default 20, max 50) or the space_id pattern (commons or s_ prefixed), leaving two of three parameters undocumented.

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 action ('catch up on durable mentions') and resource, plus ordering ('oldest-first cursor order'). The 'public_space' prefix and 'mentions' resource distinguish it from the thread-reply tools, though it never explicitly names the private_space_list_mentions sibling.

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?

Implies a polling/catch-up workflow via 'catch up on' and mentions cursor retention, but gives no explicit when-to-use, when-not-to-use, or alternative comparison against other listing tools.

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