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

Annotations only declare destructiveHint=false, so the description carries real weight by adding scope-of-effect detail: it closes only the notice row in the caller's own inbox, changes no item, and is invisible to others. This is exactly the side-effect context an agent needs beyond the annotation.

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?

A single dense sentence that front-loads the primary action and appends the exclusion and effect. The redundant parenthetical '(shared project)' costs a little, but there is no filler.

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?

For a 2-parameter tool with no output schema, the description covers purpose, directionality, scope, and exclusions. Minor gaps remain (e.g., behavior if the notice is already done, or where notice_id comes from beyond the schema note), but nothing critical is missing.

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 100%, so the baseline is 3. The description reinforces the meaning of unack: true but adds no syntax or format detail beyond what the schema already documents for notice_id and unack.

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 ... shared project notices done') and disambiguates scope by ruling out Slack workspaces ('NOT a Slack workspace'). Combined with the sibling set (complete_shared_item, list_shared_notices), an agent can tell what this targets without opening the schema.

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?

Gives clear context for both directions of the action (mark done, or unack: true to reopen) and explicitly excludes the Slack-workspace case. It does not name a competing sibling such as complete_shared_item to route between them, so it stops short of full alternative guidance.

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