mark_email

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

With no annotations, the description carries the full behavioral burden and falls short: it does not say the change is persisted server-side, whether it is reversible, whether unmentioned flags are left untouched, or whether any special permissions are required. 'Update' signals mutation but nothing about side effects or failure modes is disclosed.

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 efficient sentence with the verb front-loaded and zero padding. The hedged 'such as' phrasing slightly weakens precision but costs nothing in length.

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 flag-mutation tool with a fully documented schema and an output schema (so return values needn't be described), it is close to adequate. It still omits the important behavioral detail that null flag parameters mean 'no change' and says nothing about error conditions or idempotency.

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 adds a small amount of value by mapping natural-language flag concepts (read/starred) onto the is_read/is_flagged parameters, but it does not explain the null default semantics (null = leave unchanged) or the folder default, which the schema already covers.

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 and resource ('Update email flags') and enumerates the concrete flag operations (read/unread, starred/flagged), so an agent can distinguish it from siblings like move_email or delete_email. It does not explicitly name which sibling to use instead, but the resource is distinctive enough on its own.

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?

There is no statement of when to use this tool versus alternatives, and no prerequisites (e.g., that the message must already exist, or how it differs from read_email which presumably also marks as read). Usage is only implied by the operation name.

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