List Global Announcements

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the 'Read-only' sentence in the description is largely redundant. The one piece of new behavioral information is 'Messages are provenance-fenced', which hints that returned content is trust-labeled, but the term is never explained and nothing is said about pagination, volume, or whether dismissing affects this listing.

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 short sentences, front-loaded with the resource definition and followed by safety framing, with no wasted wording. The only blemish is the unexplained jargon phrase 'provenance-fenced', which consumes space without conveying actionable meaning to an agent.

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 zero-parameter read with a full annotation set and no output schema, the description covers identity, scope, and safety sufficiently for correct invocation. Its remaining gap is the unexplained provenance-fencing note and the lack of a pointer to the dismiss/read-marking siblings an agent would likely need next.

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 no parameters and the schema is empty, so there is nothing for the description to disambiguate. Baseline for a zero-parameter tool is 4; the description correctly signals a no-argument call by describing a single global feed.

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 gives a concrete verb-less but specific resource: 'School-wide announcements' and explains they are 'the banners your school shows everyone on the Canvas dashboard', with examples (closures, outages, deadlines). This clearly separates it in scope from course-level siblings like list_announcements, but it never names that sibling or states the contrast explicitly, so differentiation is inferred rather than declared.

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 only implied by the word 'School-wide' and by the dashboard-banner framing; an agent can guess this is the account-level feed rather than a course feed. There is no explicit 'use this when' statement, no note about when to prefer list_announcements, and no mention of how it relates to dismiss_global_announcement or mark_announcement_read.

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