mark_planner_item_complete

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

Annotations already declare this as a non-read-only, non-destructive mutation, so the description's job is to explain the blast radius — and it does: the change is confined to 'the user's private planner view' and explicitly does not submit work. It does not say whether the override is reversible or idempotent, which would round out the mutation profile.

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-loaded with the scope-limiting sentence, then the usage guidance, then args — a sensible order with no filler prose. The Args block is somewhat redundant in formatting but each line contributes parameter meaning not found in the bare schema.

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?

With an output schema present, return values need no explanation, and annotations cover the safety profile. That leaves scope, side effects, and both parameters — all addressed — so little an agent needs in order to call this correctly is absent.

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 0%, so the description carries the full burden and largely meets it: plannable_type is illustrated with concrete values ('assignment', 'quiz', 'planner_note') and plannable_id is identified as the target item's Canvas ID. It still doesn't establish whether the accepted type strings are a closed set or how they map to the tool's own naming.

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 first sentence names a specific verb and resource ('mark a planner item as complete') and immediately qualifies the mechanism ('via a planner override'). It also draws a crucial boundary — 'This does NOT submit the work' — which separates it from submission tools. It does not explicitly name the nearest sibling (dismiss_planner_item), so the distinction from dismiss-versus-complete is left implicit.

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?

"Use to silence 'you still have to do this' reminders when the work is actually done" gives a concrete triggering condition plus a real example (paper assignments submitted offline). What's missing is an explicit when-not or a named alternative, e.g. that dismissing is for work you won't do while completing is for work already done.

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