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

With no annotations, the description carries the full burden of disclosing behavior. It states the core action (marking as read) and the two operational modes, which is adequate. However, it does not mention whether the action is reversible, any permission requirements, or the effect on unread counts, which would be useful for a mutation tool.

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 description is exceptionally concise: two sentences, front-loaded with the action, and no wasted words. Every phrase carries meaning.

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 simple two-parameter tool with no output schema, the description covers the primary usage modes. It is slightly incomplete in that it does not address what happens if both id and all are supplied or the nature of the response, but these are minor gaps for such a straightforward operation.

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%, so the schema already explains both parameters. The description adds a convenience hint ('Pass id for a single notification, or all=true for all') that reinforces the conditional relationship, but it duplicates the 'required unless all=true' note already in the id property description. Minimal added value beyond the schema.

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 description uses the specific verb 'Mark' and targets the resource 'notification(s) as read,' which clearly distinguishes this from sibling tools like notification_list (listing) and notification_create (creating). The phrase 'as read' eliminates ambiguity between reading/retrieving and marking-as-read.

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 explicitly explains the two usage modes: pass an id for a single notification or use all=true for all. It gives clear context on how to invoke the tool, but does not explicitly mention exclusions or alternatives; however, the intended use is self-evident from the sibling set.

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