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

Annotations only declare destructiveHint=true and readOnlyHint=false; the description adds the far more important behavior that this tool never writes directly, returning status='confirmation_required' with an action_id and plan_token, and that the write occurs only after confirm_action. That is exactly the kind of non-obvious, safety-critical context annotations cannot express.

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?

Three short sentences, front-loaded with the action, then the id source, then the confirmation contract. No filler and no repetition of the title.

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 no output schema, the description usefully describes the return shape (status, action_id, plan_token) and the confirmation handshake, which is the main thing an agent needs. The remaining gap is the unexplained assignment_id/project_id pair, which matters for a four-required-parameter mutation.

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% across four required parameters, so the description must compensate. It explains where item_id comes from and that done is a tick/untick flag, but assignment_id and project_id are left entirely unexplained, including why both are needed.

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 pair and resource: 'Tick or untick one checklist point.' The scope (one point) and the sibling that supplies ids (erp_get_assignment) are both named, so an agent can distinguish it from erp_add_checklist_items without opening a 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 a clear precondition for use: point ids must come from erp_get_assignment, which returns the checklist. It also explains the mandatory follow-up path via confirm_action. It stops short of stating when not to use it (e.g. bulk toggling or adding new points), so it is not a full 5.

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