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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the mutation profile is known. The description adds genuinely new behavioral context beyond the annotations: the action is reversible (resolved:false reopens) and is authorization-gated to the owner or thread initiator.

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 short sentences, front-loading the operation and the toggle behavior, then the permission constraint. No filler or redundant restatement of the tool name.

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?

An output schema exists, so return values need not be described, and the description covers the operation, its reversibility, and the authorization requirement. The only gap is the absence of routing guidance against the sibling comment tools, which is minor given the low-complexity two-parameter schema.

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 100% (baseline 3), and the description adds real meaning on top: it explains the effect of resolved:false, which the schema only labels 'Default true.' It does not clarify that comment_id refers to a note id in a way beyond the schema's own wording, but the toggling semantics is a genuine addition.

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+resource ('Mark a thread as done') and discloses the toggle semantics (reopen with resolved:false). It does not name or contrast with siblings like delete_comment or list_comments, and it shifts terminology between 'thread', 'note', and 'comment', so it stops short of a 5.

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?

Clearly states who is permitted to perform the action (presentation owner or thread starter), which is the primary precondition for use. It gives no guidance on choosing this over delete_comment or on what happens if the caller lacks permission, so context is present but alternatives are absent.

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