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

With no annotations, the description carries the full burden and does so richly: it discloses the history line, watcher notices under the caller's name, that only the item's box is touched so concurrent description edits are safe, idempotent no-op behavior on an already-ticked item ('changed' false), and the permission requirement.

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 action and resource, and every clause adds a distinct behavioral fact. Slightly eroded by the awkward, run-on phrasing 'Written as a click on the item is:', which slows parsing.

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 3-param mutation tool with no output schema and no annotations, the description covers return signaling ('changed' false), failure semantics, concurrency safety, side effects, and permissions — nothing an agent needs to call it correctly is 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 100%, so baseline is 3, but the description adds real meaning: it frames 'checked' as tick/untick and documents the idempotency outcome for the checked parameter, and reinforces that 'id' comes from get_checklist.

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 ('Tick or untick') on a specific resource ('one checklist item') and identifies the source of the id via get_checklist, so it is immediately distinguishable from get_checklist and the other issue-mutation siblings.

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?

Explains the precondition (id must come from get_checklist) and the recovery path when an id resolves to nothing ('read the checklist again'), plus the required permission. It does not contrast against other mutation tools explicitly, but the context is clear enough to select it correctly.

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