Create an announcement

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

Annotations only signal openWorldHint/destructiveHint and non-read-only; the description adds real behavior: optional type defaults to info, omission of start/end makes the banner indefinite, and a 403 is returned if the plan lacks status_page_announcements_enabled. This goes beyond the structured hints and gives an agent actionable expectations. No contradiction with annotations.

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?

Two sentences, information-dense and front-loaded: the action and object come first, then behavior, then failure mode. No filler or repetition of annotation values.

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?

Given 8 parameters, no output schema, and only sparse annotations, the description supplies the important operational context: default severity, duration behavior, and an explicit error condition. A status_page_id and title/body are sufficiently clear from the schema, so nothing critical for invoking the tool correctly seems 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 coverage is already 75%, so the schema does most of the work. The description adds meaning beyond it by stating the type default, treating started_at/ended_at as an optional display window, and linking their omission to unlimited visibility. It leaves status_page_id and title semantics largely to the schema, but that is acceptable at this coverage level.

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: 'Publishes a banner announcement on the status page' and enumerates the key fields (title, body, type). This clearly identifies a create-style action and distinguishes it from announcement list/update/delete siblings, so an agent knows what resource is affected.

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?

Describes when the defaults and display-window behavior apply, including what happens if started_at/ended_at are omitted (shown until deleted/ended), and calls out the plan requirement. It does not explicitly name status_page_announcement_update/delete/list as alternatives, but the create semantics are unambiguous enough for a correct selection.

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