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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds real value beyond that by saying the item is 'marked as removed' (implying a soft state change rather than hard deletion) and by disclosing the product constraint that users cannot manually edit plan items. It does not say what happens if the item is already removed or whether the removal can be undone.

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 operation and followed by the target constraint and the editing policy. The middle sentence largely mirrors the schema's target union, which is slight redundancy, but nothing is padded or buried.

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 destructive mutation with no output schema, the description covers what the tool does and which targeting forms exist, but omits the observable outcome: whether an already-removed item errors or no-ops, what the response contains, and how removal affects plan completion state. Those gaps matter for an open-world, destructive tool.

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 50%, and the description restates the target union ('{type:"id", itemId}' or '{type:"position", position}') that the anyOf schema already encodes, adding little. The reason parameter and planId/conversationId semantics are left entirely to the schema, so the description does not compensate for the coverage 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 and resource: 'Marks one plan item as removed,' which tells an agent exactly what operation occurs. It implicitly separates removal from editing (contrasting with update_plan_item) by noting users cannot manually edit plan items, though it never names a sibling alternative explicitly.

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?

The description establishes that removal is the only sanctioned path for eliminating an item and that other edits go through chat, which is useful context. However, it gives no when-to-use distinction versus complete_plan or update_plan_item, so the agent must infer that this is for single-item removal from an active plan.

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