mark_email_read

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

No annotations are provided, so the description carries the full burden, yet it says nothing about which messages are affected (no parameters exist, so targeting is presumably implicit), whether the change is reversible, what account/permission is required, or whether it acts on a selection or a mailbox. For a mutation tool with zero annotation coverage this is a substantial gap.

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 single sentence is front-loaded with the trigger condition, which is good structure, but it is incomplete and ends mid-clause, leaving the described behavior unpredictable to the agent. Size is appropriate; delivery is not.

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?

A zero-parameter mutation with no annotations and no output schema needs the description to explain targeting and side effects; instead it is truncated and never covers the unread case or how messages are chosen. An agent cannot confidently invoke it as written.

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?

The tool takes zero parameters, so the baseline is 4 under the rubric. The description could still have explained how messages are identified given there are no inputs, but the truncation prevents that from counting against the schema layer, which has nothing to document.

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 (mark as read/unread) and resource (emails in Mac Apple Mail / Mail.app), which also implicitly separates it from m365_mark_email_read and outlook_mark_email_read by naming the client. However, the description is cut off mid-sentence, so the full scope statement is never delivered.

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 phrase 'Use this when the user wants...' does provide a trigger condition, but it terminates in 'or as unread with un...', so the unread case and any exclusions or alternative tools are left unstated. Usage intent is only implied beyond the read case.

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