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

Annotations already declare this is a non-destructive write (readOnlyHint=false, destructiveHint=false) with open-world behavior. The description adds the domain context that this is a Trainer Connect announcement but does not disclose idempotency, side effects, permissions, or what the response looks like.

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 a single front-loaded sentence with no wasted words, clearly stating the action and resource.

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 one-parameter mutation with no output schema, the description combined with annotations and the fully described schema is complete enough for correct invocation. A bit more detail on what marking as seen changes would make it fully complete.

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 single announcementId parameter is already fully documented in the schema. The description restates that the ID comes from list_announcements, matching the schema description without adding new syntax or format detail; baseline 3 applies.

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 states a specific verb (marks), resource (Trainer Connect announcement), and resulting state (seen), and references list_announcements as the source. It is clear what the tool does, but it does not explicitly differentiate itself from sibling mark_* tools such as mark_notification_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?

Usage is implied: mark an announcement as seen after obtaining its ID from list_announcements. The description gives no explicit when-to-use guidance, no exclusions, and does not name alternatives like mark_notification_read.

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