canvas_post_announcement

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

No annotations exist, so the description carries the full behavioral burden and does so well: it discloses the mutation, that students are notified, that Canvas emails the whole roster, and the irreversible consequence ('deleting the announcement afterwards does not unsend it'). This is exactly the destructive/irreversible context an agent needs before calling.

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?

Front-loads the mutation warning in bold, then the approval requirement, then the scheduling alternative, then parameter notes. Every sentence adds decision-relevant information with no filler.

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?

Covers the safety-critical behavior, the approval workflow, the scheduling option, and all four parameters. An output schema exists, so return values need not be described, leaving nothing an agent needs 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 description coverage is 0%, yet the description documents every parameter: title as subject line, message as body with HTML allowed, delayed_post_at as ISO 8601 UTC publish time, course_id as numeric id defaulting to CANVAS_DEFAULT_COURSE_ID. It fully compensates for the schema gap.

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+resource (post an announcement) and immediately characterizes what it does to the system: 'MUTATES the course — students are notified.' An agent can distinguish this from the sibling read tool canvas_list_announcements without opening the schema.

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?

Gives explicit pre-call workflow ('Show the instructor the exact title and body and get explicit approval') and an alternative mode (pass delayed_post_at to schedule instead of posting immediately). It stops short of routing the agent between this and other notifying siblings like canvas_message_students, so it is clear context rather than full when/when-not/alternatives guidance.

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